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Mansor Ahmad

UPM - Universiti Putra Malaysia, Faculty of Science: Chemistry Department, Faculty Member

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An academician with expertise in Polymer and Analytical Chemistry. Currently attached to Universiti Putra Malaysia in Serdang Selangor Malaysia. Areas of interests include nanoparticles, nanotechnology, composites and controlled-release.

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UPM - Universiti Putra Malaysia

NATIONAL DEFENCE UNIVERSITY MALAYSIA

Olushola Sunday Ayanda

Federal University,Oye-Ekiti

Shivani Pathania

Hossein Bannazadeh Baghi

Universiti Teknologi Mara

roshanak khandanlou

Charles Darwin University

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Papers by Mansor Ahmad

Article Studies on Properties of Rice Straw/Polymer Nanocomposites Based on Polycaprolactone and Fe3O4 Nanoparticles and Evaluation of Antibacterial Activity

Abstract: Modified rice straw/Fe3O4/polycaprolactone nanocomposites (ORS/Fe3O4/ PCL-NCs) have bee... more Abstract: Modified rice straw/Fe3O4/polycaprolactone nanocomposites (ORS/Fe3O4/ PCL-NCs) have been prepared for the first time using a solution casting method. The RS/Fe3O4-NCs were modified with octadecylamine (ODA) as an organic modifier. The prepared NCs were characterized by using X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The XRD results showed that as the intensity of the peaks decreased with the increase of ORS/Fe3O4-NCs content in comparison with PCL peaks, the Fe3O4-NPs peaks increased from 1.0 to 60.0 wt. %. The TEM and SEM results showed a good dispersion of ORS/Fe3O4-NCs in the PCL matrix and the spherical shape of the NPs. The TGA analysis indicated thermal stability of ORS/Fe3O4-NCs increased after incorporation with PCL but the thermal stability of ORS/Fe3O4/PCL-NCs decreased with the increase of ORS/Fe3O4-NCs content. ...

Synthesis novel antibacterial silver nanoparticles in montmorillonite by chemical reduction agent

Pelaksanaan modul pembangunan kemahiran insaniah untuk institusi pengajian tinggi

Institusi Pengajian Tinggi(IPT) Malaysia harus berupaya untuk melaksanakan tanggungjawab sebagai ... more Institusi Pengajian Tinggi(IPT) Malaysia harus berupaya untuk melaksanakan tanggungjawab sebagai penjana sumber manusia atau modal insan yang bukan sahaja berpengetahuan tetapi juga memiliki semua ciri insan kamil. Terkini, isu lambakan siswazah dan penganguran menjadi intipati perbincangan dengan menuding kepada institusi pengajian tinggi terutamanya IPT awam yang tidak peka kepada permintaan industri dan kurikulum yang kurang relevan dan ketinggalan sehingga graduan yang dihasilkan tidak memenuhi ekspektasi majikan. Sehubungan itu juga, keupayaan graduan dalam menangani kehidupan berkerjaya selepas menamatkan pengajian dipersoalkan kerana kekurangan kemahiran berkomunikasi, tiada sikap persaingan yang positif, tidak mampu melihat masalah sebagai peluang dan cabaran, selain dari tidak proaktif. Oleh itu, perhatian perlu diberikan dengan menilai dari akar umbi perubahan dan inisiatif yang perlu dilakukan bagi meraih semula kredibiliti IPTA yang tercalar dalam menyumbangkan modal insan yang bermutu dalam pembentukan pembangunan negara. Graduan yang dikeluarkan oleh IPT bukan sahaja mampu mencurahkan sumbangan di peringkat nasional tetapi mampu mendapat tempat di pasaran kerja antarabangsa yang sekaligus mampu menangani masalah pengangguran siswazah. Kertas ini melaporkan hasil dari bengkel Kemahiran Insaniah yang diadakan dengan tujuan memberi pendedahan dan latihan bagi dilaksanakan di IPT masing-masing.

Synthesis, Characterization and Thermal Properties of New and Known 1,3-Benzo- and Naphtho-Oxazine Monomers Obtained Using a Modified Step-wise Procedure

British Journal of Applied Science & Technology, 2016

Biochar as a sorbent for contaminant management in soil and water: A review

Chemosphere, 2014

This manuscript reviews recent findings published on biochar. Physical architecture and compositi... more This manuscript reviews recent findings published on biochar. Physical architecture and composition of biochars are critical for soil and water remediation. Sorption capacity depends on surface area, microporosity, and hydrophobicity of biochar. Long-term effects of biochar on contaminant stability in soil should be investigated.

Copolymerization of Ethyl Methacrylate and Vinyl Acetate with Methacrylamide: Synthesis, Characterization and Reactivity Ratios

Egyptian Journal of Chemistry, 2022

The properties of polymers can be most effectively modified with the help of the technique of cop... more The properties of polymers can be most effectively modified with the help of the technique of copolymerisation. In this study, solution polymerization technique was used to obtain low conversion linear copolymer, in order to determine the reactivity ratios of the ethyl methacrylate EMA, vinyl acetate VAC, and methacrylamide MAM. These monomers were used in the synthesis of EMA-co-MAM and VAC-co-MAM with different compositions, initiated by benzoyl peroxide (BPO). The copolymers were characterized by Fourier Transform Infrared (FTIR) and their thermal stability was studied by thermogravimetric analysis (TGA). Their compositions and reactivity ratios (r 1 , r 2) were determined by elemental analysis using linearization methods proposed by Fineman-Ross and Kelen-Tudos, and intersection method proposed by Mayo-Lewis procedure. The derived (r 1 , r 2) for EMA-co-MAM and VAC-co-MAM are: (0.197, 0.230) and (0.294, 4.314), respectively. The microstructure of copolymers and sequence distribution of monomers in the copolymers were calculated by statistical method, the derived results are in agreement with (r 1 , r 2) values. EMA with MAM form alternative copolymer whilst VACco-MAM tends to be block with MAM. No study has been reported on the copolymerization and reactivity relationships of hydrophobic monomers (EMA, VAC) with hydrophilic monomers (MAM).

Article Rapid Adsorption of Heavy Metals by Fe3O4/Talc Nanocomposite and Optimization Study Using Response Surface Methodology

Abstract: Fe3O4/talc nanocomposite was used for removal of Cu(II), Ni(II), and Pb(II) ions from a... more Abstract: Fe3O4/talc nanocomposite was used for removal of Cu(II), Ni(II), and Pb(II) ions from aqueous solutions. Experiments were designed by response surface methodology (RSM) and a quadratic model was used to predict the variables. The adsorption parameters such as adsorbent dosage, removal time, and initial ion concentration were used as the independent variables and their effects on heavy metal ion removal were investigated. Analysis of variance was incorporated to judge the adequacy of the models. Optimal conditions with initial heavy metal ion concentration of 100, 92 and 270 mg/L, 120 s of removal time and 0.12 g of adsorbent amount resulted in 72.15%, 50.23%, and 91.35%

Poly (lactic acid)/organoclay blend nanocomposites: Structural, mechanical and microstructural properties

Digest Journal of Nanomaterials and Biostructures, 2015

Poly (lactic acid)/clay nanocomposites were prepared by solution-casting and meltblending techniq... more Poly (lactic acid)/clay nanocomposites were prepared by solution-casting and meltblending techniques, and their morphologies and mechanical properties were studied. Xray diffractograms revealed an intercalated–exfoliated mixed structure for the nanocomposites obtained by both techniques. TEM images show a good organoclay dispersion degree. The mechanical properties of nanocomposites from the melt-blending technique were superior to those obtained by solution-casting method. In both cases, the highest elongation at break and Young’s modulus were achieved at5wt%octadecylaminemontmorillonite (ODA-MMT) content.

Preparation, characterization and catalytic activity of biomaterial-supported copper nanoparticles

Research on Chemical Intermediates, 2016

Synthesis of copper nanoparticles was carried out with nanocrystalline cellulose (NCC) as a suppo... more Synthesis of copper nanoparticles was carried out with nanocrystalline cellulose (NCC) as a support by reducing CuSO4•5H2O ions using hydrazine. Ascorbic acid and aqueous NaOH were also used as an antioxidant and pH controller, respectively. The synthesized copper nanoparticles supported on NCC (CuNPs@NCC) were characterized by UV-vis, XRD, TEM, XRF, TGA, DSC, N2 adsorption-desorption method at 77 K and FTIR. The UV-vis confirmed the formation and stability of the CuNPs, which indicated that the maximum absorbance of CuNPs@NCC was at 590 nm due to the surface plasmon absorption of CuNPs. Morphological characterization clearly showed the formation of a spherical structure of the CuNPs with the mean diameter and standard deviation of 2.71 ± 1.12 nm. Similarly, XRD showed that the synthesized CuNPs@NCC was of high purity. The thermal analysis showed that the CuNPs@NCC exhibited better thermal behaviors than NCC. BET surface area revealed that the N2 adsorption-desorption isotherms of CuNPs@NCC featured a type IV isotherm with an H3 hysterisis loop. This chemical method is simple, cost effective, and environmentally friendly. Compared to NCC-supported CuNPs and unsupported CuNPs, the as-prepared CuNPs@NCC exhibit a superior catalytic activity and high sustainability for the reduction of methylene blue with NaBH4 in aqueous solution at room temperature. The CuNPs@NCC achieved complete reduction of MB with completion time, rate constant and correlation coefficient (R 2) of 12 min, 0.7421 min−1 and 0.9922, respectively.

Synthesis of Nanocrystalline Cellulose Stabilized Copper Nanoparticles

Journal of Nanomaterials, 2016

A chemical reduction method was employed for the synthesis of copper nanoparticles stabilized by ... more A chemical reduction method was employed for the synthesis of copper nanoparticles stabilized by nanocrystalline cellulose (NCC) using different concentrations of copper salt in aqueous solution under atmospheric air. CuSO4·5H2O salt and hydrazine were used as metal ion precursor and reducing agent, respectively. Ascorbic acid and aqueous NaOH were also used as an antioxidant and a pH moderator, respectively. The number of CuNPs increased with increasing concentration of the precursor salt. The formation of copper nanoparticles stabilized by NCC (CuNPs@NCC) was investigated by UV-visible spectroscopy (UV-vis), where the surface absorption maximum was observed at 590 nm. X-ray diffraction (XRD) analysis showed that the CuNPs@NCC are of a face-centered cubic structure. Moreover, the morphology of the CuNPs@NCC was investigated using transmission electron microscope (TEM) and field emission scanning electron microscope (FESEM), which showed well-dispersed CuNPs with an average particle...

PREPARATION OF gamma-Al2O3 NANOCRYSTALLITES BY SOL-GEL AUTO COMBUSTION PROCESS AND PRODUCTION OF Al-Al2O3 ALUMINUM MATRIX COMPOSITES

Thermal diffusivity of silver metallic nanoparticles in clay matrix

In this work, we have applied thermal lens (TL) technique to measure thermal diffusivity of clay ... more In this work, we have applied thermal lens (TL) technique to measure thermal diffusivity of clay suspensions containing metallic silver nanoparticles (Ag-NPs) prepared by chemical reduction method in different concentration. This study carried out with diode laser (wavelength 514 nm, power 80mW) as the excitation source and intensity stabilized He-Ne laser as a probe beam. The results show that thermal diffusivity of fluid increases when Ag-NPs concentrations increase.

Preparation and Characterization of Polyhydroxyalkanoates Macroporous Scaffold Through Enzyme-Mediated Modifications

Applied Biochemistry and Biotechnology, 2013

Polyhydroxyalkanoates (PHAs) are hydrophobic biodegradable thermoplastics that have received cons... more Polyhydroxyalkanoates (PHAs) are hydrophobic biodegradable thermoplastics that have received considerable attention in biomedical applications due to their biocompatibility, mechanical properties, and biodegradability. In this study, the degradation rate was regulated by optimizing the interaction of parameters that influence the enzymatic degradation of P(3HB) film using response surface methodology (RSM). The RSM model was experimentally validated yielding a maximum 21 % weight loss, which represents onefold increment in percentage weight loss in comparison with the conventional method. By using the optimized condition, the enzymatic degradation by an extracellular PHA depolymerase from Acidovorax sp. DP5 was studied at 37 C and pH 9.0 on different types of PHA films with various monomer compositions. Surface modification of scaffold was employed using enzymatic technique to create highly porous scaffold with a large surface to volume ratio, which makes them attractive as potential tissue scaffold in biomedical field. Scanning electron microscopy revealed that the surface of salt-leached films was more porous compared with the solvent-cast films, and hence, increased the degradation rate of salt-leached films. Apparently, enzymatic degradation behaviors of PHA films were determined by several factors such as monomer composition, crystallinity, molecular weight, porosity, and roughness of the surface. The hydrophilicity and water uptake of degraded salt-leached film of P(3HB-co-70%4HB) were enhanced by incorporating chitosan or alginate. Salt-leached technique followed by partial enzymatic degradation would enhance the cell attachment and suitable for biomedical as a scaffold.

Antibacterial effect of silver nanoparticles on Staphylococcus aureus

BioMetals, 2010

The antibacterial activity and mechanism of silver nanoparticles (Ag-NPs) on Staphylococcus aureu... more The antibacterial activity and mechanism of silver nanoparticles (Ag-NPs) on Staphylococcus aureus ATCC 6538P were investigated in this study. The experiment results showed the minimum bactericidal concentration (MBC) of Ag-NPs to S. aureus was 20 μg/ml. Moreover, when bacteria cells were exposed to 50 μg/ml Ag-NPs for 6 h, the cell DNA was condensed to a tension state and could have lost their

Synthesis and properties of vinylpyrrolidone/ (trimethoxysilyl)propyl methacrylate gels containing different amounts of crosslinking agent

Polimery, 2018

High conversion copolymers containing 90 wt % of N-vinylpyrrolidone (NVP) and 10 wt % of 3-(trime... more High conversion copolymers containing 90 wt % of N-vinylpyrrolidone (NVP) and 10 wt % of 3-(trimethoxysilyl)propyl methacrylate (TMSPM) with 0, 1, 2, 3 and 4 wt % (in conversion to mass of NVP/TMSPM) of ethylene glycoldimethacrylate (EGDMA) as crosslinker have been successfully synthesized. Proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared spectroscopy (FT-IR) were employed to characterize the resulting copolymers. The effect of EGDMA amount on the mechanical and thermal properties, swelling parameters, clarity, and oxygen permeability of the prepared xerogels and hydrogels were studied. 3 wt % of EGDMA is required to obtain clear xerogels and hydrogels. The water content (EWC), volume fraction of polymer (φ2) and weight loss during swelling decrease with increasing EGDMA content. Young's and shear modulus (E and G) increase as EGDMA content increases, the values of E and G are 0.570-3.531 MPa and 0.217-1.359 MPa, respectively. The hydrogels were characterized in terms of modulus crosslinking density (ve and vt) and polymer-solvent interaction parameters (χ). The results are 0.220-0.613 mol/dm3 for ve, 0.105-0.441 mol/dm3 for vt, and 0.595-0.822 for χ. Thermal properties enhance by adding EGDMA whereas the oxygen permeability (P) of hydrogels decreases from 48.6 to 44.3 as water content decrease from 70.3 to 55.1.

Acid Hydrolysis-Mediated preparation of Nanocrystalline Cellulose from Rice Straw

International Journal of Nanomaterials, Nanotechnology and Nanomedicine, 2017

Rice straw is available in abundance as an agricultural waste and has been used in various applic... more Rice straw is available in abundance as an agricultural waste and has been used in various applications. It is utilized as a source of cellulose and is attractive in biofuels, biomedical, and other applications. The present study investigates the surface morphology, structural properties, and thermal properties of nanocrystalline cellulose (NCC) isolated by acid hydrolysis of rice straw. Surface morphology, transmission electron microscopy (TEM), structural properties, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Energy Dispersive X-ray Spectroscopy (EDX) of the NCCs were carried out. Morphology of the rice straw changes with each chemical treatment, and TEM images confi rmed that the extraction of the NCC was successful, which had a rod-like shape. A constant and dynamic reduction in the thermal stability of the NCC happened as the hydrolysis time increase, which was most likely because to the high sulfation rate. These results demonstrate an effi cient route to preparing high-yield NCC.

Effect of Gelatin-Stabilized Copper Nanoparticles on Catalytic Reduction of Methylene Blue

Nanoscale Research Letters, 2016

The synthesis of copper nanoparticles was carried out with gelatin as a stabilizer by reducing Cu... more The synthesis of copper nanoparticles was carried out with gelatin as a stabilizer by reducing CuSO 4 .5H 2 O ions using hydrazine. Ascorbic acid and aqueous NaOH were also used as an antioxidant and pH controller, respectively. The effects of NaOH, hydrazine, and concentration of gelatin as stabilizer were studied. The synthesized copper nanoparticles were characterized by UV-vis spectroscopy, XRD, zeta potential measurements, FTIR, EDX, FESEM, and TEM. The formation of CuNPs@Gelatin is initially confirmed by UV-vis spectroscopic analysis with the characteristic band at 583 nm. XRD and TEM reports revealed that CuNPs@Gelatin (0.75 wt.%) is highly crystalline and spherical in shape with optimum average size of 4.21 ± 0.95 nm. FTIR studies indicated the presence of amide group on the surface of the CuNPs indicating the stability of CuNPs which is further supported by zeta potential measurements with the negative optimum value of −37.90 ± 0.6 mV. The CuNPs@G4 showed a good catalytic activity against methylene blue (MB) reduction using NaBH 4 as a reducing agent in an aqueous solution. The best enhanced properties of CuNPs@G4 were found for the 0.75 wt.% gelatin concentration. Thermodynamic parameters (ΔH and ΔS) indicate that under the studied temperature, the reduction of MB by CuNPs@G4 is not feasible and had endothermic in nature.

Enhancement of heavy metals sorption via nanocomposites of rice straw and Fe3O4 nanoparticles using artificial neural network (ANN)

Ecological Engineering, 2016

The artificial neural network (ANN) modeling of adsorption of Pb(II) and Cu(II) was carried out f... more The artificial neural network (ANN) modeling of adsorption of Pb(II) and Cu(II) was carried out for determination of the optimum values of the variables to get the maximum removal efficiency. The input variables were initial ion concentration, adsorbent dosage, and removal time, while the removal efficiency was considered as output. The performed experiments were designed into two data sets including training, and testing sets. To acquire the optimum topologies, ANN was trained by quick propagation (QP), Batch Back Propagation (BBP), Incremental Back Propagation (IBP), genetic algorithm (GA) and Levenberg-Marquardt (LM) algorithms for testing data set. The topologies were defined by the indicator of minimized root mean squared error (RMSE) for each algorithm. According to the indicator, the IBP-3-9-2 was selected as the optimized topologies for heavy metal removal, due to the minimum RMSE and maximum R-squared.

Synthesis and Characterization of New 3,4-Dihydro-2H-benzo- and Naphtho-1,3-oxazine Derivatives

Asian Journal of Chemistry, 2016

The synthesis of benzoxazine compounds dates back over 70 years [1-4] but their potential was onl... more The synthesis of benzoxazine compounds dates back over 70 years [1-4] but their potential was only realized recently [5]. Among all benzoxazine compounds, 1,3-benzoxazine have received greater attention as they are used in the production of polymeric materials [6-8] and are also of significant interest in pharmacological fields [9]. 1,3-Benzoxazines as monomers are used in the synthesis of a new type of phenolic resins called polybenzoxazines through thermally activated ring-opening polymerization [10,11]. These polybenzoxazines possesses not only the properties of traditional phenolic resins but other unique properties such as low water absorption, high modulus, high strength, high glass transition temperatures, high char yield and low volumetric shrinkage upon curing [12-15]. Furthermore, 1,3-benzoxazines are known for their wide range of biological activities and hence used as fungicides, bactericide, anti-inflammatory, antidepressants and antitumor agents [16,17]. Numerous approaches are used for the synthesis of 1,3benzoxazine compounds using different solvents [18-20]. Among the approaches is the step-wise procedure which has recently gained considerable interest and more importantly tolerates various functional groups [21]. For this reason, the

Copolymerization of Tris(methoxyethoxy)vinyl Silane with N-Vinyl Pyrrolidone: Synthesis, Characterization, and Reactivity Relationships

International Journal of Polymer Science, 2015

Copolymer of tris(methoxyethoxy)vinyl silane (TMEVS) with N-vinyl pyrrolidone (NVP) was synthesiz... more Copolymer of tris(methoxyethoxy)vinyl silane (TMEVS) with N-vinyl pyrrolidone (NVP) was synthesized by free radical polymerization in dry benzene at 70°C using benzoyl peroxide (BPO) as initiator. The copolymer was characterized by viscometer, FTIR, and1H-NMR and its thermal properties were studied by DSC and TGA. The copolymer composition was determined by elemental analysis. The monomer reactivity ratios were calculated by linearization methods proposed by Fineman-Ross and Kelen-Tudos. The intersection method was proposed by Mayo-Lewis and nonlinear method was proposed by curve-fitting procedure. The microstructure of copolymer and sequence distribution of monomers in the copolymer were calculated by statistical method.

Article Studies on Properties of Rice Straw/Polymer Nanocomposites Based on Polycaprolactone and Fe3O4 Nanoparticles and Evaluation of Antibacterial Activity

Abstract: Modified rice straw/Fe3O4/polycaprolactone nanocomposites (ORS/Fe3O4/ PCL-NCs) have bee... more Abstract: Modified rice straw/Fe3O4/polycaprolactone nanocomposites (ORS/Fe3O4/ PCL-NCs) have been prepared for the first time using a solution casting method. The RS/Fe3O4-NCs were modified with octadecylamine (ODA) as an organic modifier. The prepared NCs were characterized by using X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The XRD results showed that as the intensity of the peaks decreased with the increase of ORS/Fe3O4-NCs content in comparison with PCL peaks, the Fe3O4-NPs peaks increased from 1.0 to 60.0 wt. %. The TEM and SEM results showed a good dispersion of ORS/Fe3O4-NCs in the PCL matrix and the spherical shape of the NPs. The TGA analysis indicated thermal stability of ORS/Fe3O4-NCs increased after incorporation with PCL but the thermal stability of ORS/Fe3O4/PCL-NCs decreased with the increase of ORS/Fe3O4-NCs content. ...

Synthesis novel antibacterial silver nanoparticles in montmorillonite by chemical reduction agent

Pelaksanaan modul pembangunan kemahiran insaniah untuk institusi pengajian tinggi

Institusi Pengajian Tinggi(IPT) Malaysia harus berupaya untuk melaksanakan tanggungjawab sebagai ... more Institusi Pengajian Tinggi(IPT) Malaysia harus berupaya untuk melaksanakan tanggungjawab sebagai penjana sumber manusia atau modal insan yang bukan sahaja berpengetahuan tetapi juga memiliki semua ciri insan kamil. Terkini, isu lambakan siswazah dan penganguran menjadi intipati perbincangan dengan menuding kepada institusi pengajian tinggi terutamanya IPT awam yang tidak peka kepada permintaan industri dan kurikulum yang kurang relevan dan ketinggalan sehingga graduan yang dihasilkan tidak memenuhi ekspektasi majikan. Sehubungan itu juga, keupayaan graduan dalam menangani kehidupan berkerjaya selepas menamatkan pengajian dipersoalkan kerana kekurangan kemahiran berkomunikasi, tiada sikap persaingan yang positif, tidak mampu melihat masalah sebagai peluang dan cabaran, selain dari tidak proaktif. Oleh itu, perhatian perlu diberikan dengan menilai dari akar umbi perubahan dan inisiatif yang perlu dilakukan bagi meraih semula kredibiliti IPTA yang tercalar dalam menyumbangkan modal insan yang bermutu dalam pembentukan pembangunan negara. Graduan yang dikeluarkan oleh IPT bukan sahaja mampu mencurahkan sumbangan di peringkat nasional tetapi mampu mendapat tempat di pasaran kerja antarabangsa yang sekaligus mampu menangani masalah pengangguran siswazah. Kertas ini melaporkan hasil dari bengkel Kemahiran Insaniah yang diadakan dengan tujuan memberi pendedahan dan latihan bagi dilaksanakan di IPT masing-masing.

Synthesis, Characterization and Thermal Properties of New and Known 1,3-Benzo- and Naphtho-Oxazine Monomers Obtained Using a Modified Step-wise Procedure

British Journal of Applied Science & Technology, 2016

Biochar as a sorbent for contaminant management in soil and water: A review

Chemosphere, 2014

This manuscript reviews recent findings published on biochar. Physical architecture and compositi... more This manuscript reviews recent findings published on biochar. Physical architecture and composition of biochars are critical for soil and water remediation. Sorption capacity depends on surface area, microporosity, and hydrophobicity of biochar. Long-term effects of biochar on contaminant stability in soil should be investigated.

Copolymerization of Ethyl Methacrylate and Vinyl Acetate with Methacrylamide: Synthesis, Characterization and Reactivity Ratios

Egyptian Journal of Chemistry, 2022

The properties of polymers can be most effectively modified with the help of the technique of cop... more The properties of polymers can be most effectively modified with the help of the technique of copolymerisation. In this study, solution polymerization technique was used to obtain low conversion linear copolymer, in order to determine the reactivity ratios of the ethyl methacrylate EMA, vinyl acetate VAC, and methacrylamide MAM. These monomers were used in the synthesis of EMA-co-MAM and VAC-co-MAM with different compositions, initiated by benzoyl peroxide (BPO). The copolymers were characterized by Fourier Transform Infrared (FTIR) and their thermal stability was studied by thermogravimetric analysis (TGA). Their compositions and reactivity ratios (r 1 , r 2) were determined by elemental analysis using linearization methods proposed by Fineman-Ross and Kelen-Tudos, and intersection method proposed by Mayo-Lewis procedure. The derived (r 1 , r 2) for EMA-co-MAM and VAC-co-MAM are: (0.197, 0.230) and (0.294, 4.314), respectively. The microstructure of copolymers and sequence distribution of monomers in the copolymers were calculated by statistical method, the derived results are in agreement with (r 1 , r 2) values. EMA with MAM form alternative copolymer whilst VACco-MAM tends to be block with MAM. No study has been reported on the copolymerization and reactivity relationships of hydrophobic monomers (EMA, VAC) with hydrophilic monomers (MAM).

Article Rapid Adsorption of Heavy Metals by Fe3O4/Talc Nanocomposite and Optimization Study Using Response Surface Methodology

Abstract: Fe3O4/talc nanocomposite was used for removal of Cu(II), Ni(II), and Pb(II) ions from a... more Abstract: Fe3O4/talc nanocomposite was used for removal of Cu(II), Ni(II), and Pb(II) ions from aqueous solutions. Experiments were designed by response surface methodology (RSM) and a quadratic model was used to predict the variables. The adsorption parameters such as adsorbent dosage, removal time, and initial ion concentration were used as the independent variables and their effects on heavy metal ion removal were investigated. Analysis of variance was incorporated to judge the adequacy of the models. Optimal conditions with initial heavy metal ion concentration of 100, 92 and 270 mg/L, 120 s of removal time and 0.12 g of adsorbent amount resulted in 72.15%, 50.23%, and 91.35%

Poly (lactic acid)/organoclay blend nanocomposites: Structural, mechanical and microstructural properties

Digest Journal of Nanomaterials and Biostructures, 2015

Poly (lactic acid)/clay nanocomposites were prepared by solution-casting and meltblending techniq... more Poly (lactic acid)/clay nanocomposites were prepared by solution-casting and meltblending techniques, and their morphologies and mechanical properties were studied. Xray diffractograms revealed an intercalated–exfoliated mixed structure for the nanocomposites obtained by both techniques. TEM images show a good organoclay dispersion degree. The mechanical properties of nanocomposites from the melt-blending technique were superior to those obtained by solution-casting method. In both cases, the highest elongation at break and Young’s modulus were achieved at5wt%octadecylaminemontmorillonite (ODA-MMT) content.

Preparation, characterization and catalytic activity of biomaterial-supported copper nanoparticles

Research on Chemical Intermediates, 2016

Synthesis of copper nanoparticles was carried out with nanocrystalline cellulose (NCC) as a suppo... more Synthesis of copper nanoparticles was carried out with nanocrystalline cellulose (NCC) as a support by reducing CuSO4•5H2O ions using hydrazine. Ascorbic acid and aqueous NaOH were also used as an antioxidant and pH controller, respectively. The synthesized copper nanoparticles supported on NCC (CuNPs@NCC) were characterized by UV-vis, XRD, TEM, XRF, TGA, DSC, N2 adsorption-desorption method at 77 K and FTIR. The UV-vis confirmed the formation and stability of the CuNPs, which indicated that the maximum absorbance of CuNPs@NCC was at 590 nm due to the surface plasmon absorption of CuNPs. Morphological characterization clearly showed the formation of a spherical structure of the CuNPs with the mean diameter and standard deviation of 2.71 ± 1.12 nm. Similarly, XRD showed that the synthesized CuNPs@NCC was of high purity. The thermal analysis showed that the CuNPs@NCC exhibited better thermal behaviors than NCC. BET surface area revealed that the N2 adsorption-desorption isotherms of CuNPs@NCC featured a type IV isotherm with an H3 hysterisis loop. This chemical method is simple, cost effective, and environmentally friendly. Compared to NCC-supported CuNPs and unsupported CuNPs, the as-prepared CuNPs@NCC exhibit a superior catalytic activity and high sustainability for the reduction of methylene blue with NaBH4 in aqueous solution at room temperature. The CuNPs@NCC achieved complete reduction of MB with completion time, rate constant and correlation coefficient (R 2) of 12 min, 0.7421 min−1 and 0.9922, respectively.

Synthesis of Nanocrystalline Cellulose Stabilized Copper Nanoparticles

Journal of Nanomaterials, 2016

A chemical reduction method was employed for the synthesis of copper nanoparticles stabilized by ... more A chemical reduction method was employed for the synthesis of copper nanoparticles stabilized by nanocrystalline cellulose (NCC) using different concentrations of copper salt in aqueous solution under atmospheric air. CuSO4·5H2O salt and hydrazine were used as metal ion precursor and reducing agent, respectively. Ascorbic acid and aqueous NaOH were also used as an antioxidant and a pH moderator, respectively. The number of CuNPs increased with increasing concentration of the precursor salt. The formation of copper nanoparticles stabilized by NCC (CuNPs@NCC) was investigated by UV-visible spectroscopy (UV-vis), where the surface absorption maximum was observed at 590 nm. X-ray diffraction (XRD) analysis showed that the CuNPs@NCC are of a face-centered cubic structure. Moreover, the morphology of the CuNPs@NCC was investigated using transmission electron microscope (TEM) and field emission scanning electron microscope (FESEM), which showed well-dispersed CuNPs with an average particle...

PREPARATION OF gamma-Al2O3 NANOCRYSTALLITES BY SOL-GEL AUTO COMBUSTION PROCESS AND PRODUCTION OF Al-Al2O3 ALUMINUM MATRIX COMPOSITES

Thermal diffusivity of silver metallic nanoparticles in clay matrix

In this work, we have applied thermal lens (TL) technique to measure thermal diffusivity of clay ... more In this work, we have applied thermal lens (TL) technique to measure thermal diffusivity of clay suspensions containing metallic silver nanoparticles (Ag-NPs) prepared by chemical reduction method in different concentration. This study carried out with diode laser (wavelength 514 nm, power 80mW) as the excitation source and intensity stabilized He-Ne laser as a probe beam. The results show that thermal diffusivity of fluid increases when Ag-NPs concentrations increase.

Preparation and Characterization of Polyhydroxyalkanoates Macroporous Scaffold Through Enzyme-Mediated Modifications

Applied Biochemistry and Biotechnology, 2013

Polyhydroxyalkanoates (PHAs) are hydrophobic biodegradable thermoplastics that have received cons... more Polyhydroxyalkanoates (PHAs) are hydrophobic biodegradable thermoplastics that have received considerable attention in biomedical applications due to their biocompatibility, mechanical properties, and biodegradability. In this study, the degradation rate was regulated by optimizing the interaction of parameters that influence the enzymatic degradation of P(3HB) film using response surface methodology (RSM). The RSM model was experimentally validated yielding a maximum 21 % weight loss, which represents onefold increment in percentage weight loss in comparison with the conventional method. By using the optimized condition, the enzymatic degradation by an extracellular PHA depolymerase from Acidovorax sp. DP5 was studied at 37 C and pH 9.0 on different types of PHA films with various monomer compositions. Surface modification of scaffold was employed using enzymatic technique to create highly porous scaffold with a large surface to volume ratio, which makes them attractive as potential tissue scaffold in biomedical field. Scanning electron microscopy revealed that the surface of salt-leached films was more porous compared with the solvent-cast films, and hence, increased the degradation rate of salt-leached films. Apparently, enzymatic degradation behaviors of PHA films were determined by several factors such as monomer composition, crystallinity, molecular weight, porosity, and roughness of the surface. The hydrophilicity and water uptake of degraded salt-leached film of P(3HB-co-70%4HB) were enhanced by incorporating chitosan or alginate. Salt-leached technique followed by partial enzymatic degradation would enhance the cell attachment and suitable for biomedical as a scaffold.

Antibacterial effect of silver nanoparticles on Staphylococcus aureus

BioMetals, 2010

The antibacterial activity and mechanism of silver nanoparticles (Ag-NPs) on Staphylococcus aureu... more The antibacterial activity and mechanism of silver nanoparticles (Ag-NPs) on Staphylococcus aureus ATCC 6538P were investigated in this study. The experiment results showed the minimum bactericidal concentration (MBC) of Ag-NPs to S. aureus was 20 μg/ml. Moreover, when bacteria cells were exposed to 50 μg/ml Ag-NPs for 6 h, the cell DNA was condensed to a tension state and could have lost their

Synthesis and properties of vinylpyrrolidone/ (trimethoxysilyl)propyl methacrylate gels containing different amounts of crosslinking agent

Polimery, 2018

High conversion copolymers containing 90 wt % of N-vinylpyrrolidone (NVP) and 10 wt % of 3-(trime... more High conversion copolymers containing 90 wt % of N-vinylpyrrolidone (NVP) and 10 wt % of 3-(trimethoxysilyl)propyl methacrylate (TMSPM) with 0, 1, 2, 3 and 4 wt % (in conversion to mass of NVP/TMSPM) of ethylene glycoldimethacrylate (EGDMA) as crosslinker have been successfully synthesized. Proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared spectroscopy (FT-IR) were employed to characterize the resulting copolymers. The effect of EGDMA amount on the mechanical and thermal properties, swelling parameters, clarity, and oxygen permeability of the prepared xerogels and hydrogels were studied. 3 wt % of EGDMA is required to obtain clear xerogels and hydrogels. The water content (EWC), volume fraction of polymer (φ2) and weight loss during swelling decrease with increasing EGDMA content. Young's and shear modulus (E and G) increase as EGDMA content increases, the values of E and G are 0.570-3.531 MPa and 0.217-1.359 MPa, respectively. The hydrogels were characterized in terms of modulus crosslinking density (ve and vt) and polymer-solvent interaction parameters (χ). The results are 0.220-0.613 mol/dm3 for ve, 0.105-0.441 mol/dm3 for vt, and 0.595-0.822 for χ. Thermal properties enhance by adding EGDMA whereas the oxygen permeability (P) of hydrogels decreases from 48.6 to 44.3 as water content decrease from 70.3 to 55.1.

Acid Hydrolysis-Mediated preparation of Nanocrystalline Cellulose from Rice Straw

International Journal of Nanomaterials, Nanotechnology and Nanomedicine, 2017

Rice straw is available in abundance as an agricultural waste and has been used in various applic... more Rice straw is available in abundance as an agricultural waste and has been used in various applications. It is utilized as a source of cellulose and is attractive in biofuels, biomedical, and other applications. The present study investigates the surface morphology, structural properties, and thermal properties of nanocrystalline cellulose (NCC) isolated by acid hydrolysis of rice straw. Surface morphology, transmission electron microscopy (TEM), structural properties, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Energy Dispersive X-ray Spectroscopy (EDX) of the NCCs were carried out. Morphology of the rice straw changes with each chemical treatment, and TEM images confi rmed that the extraction of the NCC was successful, which had a rod-like shape. A constant and dynamic reduction in the thermal stability of the NCC happened as the hydrolysis time increase, which was most likely because to the high sulfation rate. These results demonstrate an effi cient route to preparing high-yield NCC.

Effect of Gelatin-Stabilized Copper Nanoparticles on Catalytic Reduction of Methylene Blue

Nanoscale Research Letters, 2016

The synthesis of copper nanoparticles was carried out with gelatin as a stabilizer by reducing Cu... more The synthesis of copper nanoparticles was carried out with gelatin as a stabilizer by reducing CuSO 4 .5H 2 O ions using hydrazine. Ascorbic acid and aqueous NaOH were also used as an antioxidant and pH controller, respectively. The effects of NaOH, hydrazine, and concentration of gelatin as stabilizer were studied. The synthesized copper nanoparticles were characterized by UV-vis spectroscopy, XRD, zeta potential measurements, FTIR, EDX, FESEM, and TEM. The formation of CuNPs@Gelatin is initially confirmed by UV-vis spectroscopic analysis with the characteristic band at 583 nm. XRD and TEM reports revealed that CuNPs@Gelatin (0.75 wt.%) is highly crystalline and spherical in shape with optimum average size of 4.21 ± 0.95 nm. FTIR studies indicated the presence of amide group on the surface of the CuNPs indicating the stability of CuNPs which is further supported by zeta potential measurements with the negative optimum value of −37.90 ± 0.6 mV. The CuNPs@G4 showed a good catalytic activity against methylene blue (MB) reduction using NaBH 4 as a reducing agent in an aqueous solution. The best enhanced properties of CuNPs@G4 were found for the 0.75 wt.% gelatin concentration. Thermodynamic parameters (ΔH and ΔS) indicate that under the studied temperature, the reduction of MB by CuNPs@G4 is not feasible and had endothermic in nature.

Enhancement of heavy metals sorption via nanocomposites of rice straw and Fe3O4 nanoparticles using artificial neural network (ANN)

Ecological Engineering, 2016

The artificial neural network (ANN) modeling of adsorption of Pb(II) and Cu(II) was carried out f... more The artificial neural network (ANN) modeling of adsorption of Pb(II) and Cu(II) was carried out for determination of the optimum values of the variables to get the maximum removal efficiency. The input variables were initial ion concentration, adsorbent dosage, and removal time, while the removal efficiency was considered as output. The performed experiments were designed into two data sets including training, and testing sets. To acquire the optimum topologies, ANN was trained by quick propagation (QP), Batch Back Propagation (BBP), Incremental Back Propagation (IBP), genetic algorithm (GA) and Levenberg-Marquardt (LM) algorithms for testing data set. The topologies were defined by the indicator of minimized root mean squared error (RMSE) for each algorithm. According to the indicator, the IBP-3-9-2 was selected as the optimized topologies for heavy metal removal, due to the minimum RMSE and maximum R-squared.

Synthesis and Characterization of New 3,4-Dihydro-2H-benzo- and Naphtho-1,3-oxazine Derivatives

Asian Journal of Chemistry, 2016

The synthesis of benzoxazine compounds dates back over 70 years [1-4] but their potential was onl... more The synthesis of benzoxazine compounds dates back over 70 years [1-4] but their potential was only realized recently [5]. Among all benzoxazine compounds, 1,3-benzoxazine have received greater attention as they are used in the production of polymeric materials [6-8] and are also of significant interest in pharmacological fields [9]. 1,3-Benzoxazines as monomers are used in the synthesis of a new type of phenolic resins called polybenzoxazines through thermally activated ring-opening polymerization [10,11]. These polybenzoxazines possesses not only the properties of traditional phenolic resins but other unique properties such as low water absorption, high modulus, high strength, high glass transition temperatures, high char yield and low volumetric shrinkage upon curing [12-15]. Furthermore, 1,3-benzoxazines are known for their wide range of biological activities and hence used as fungicides, bactericide, anti-inflammatory, antidepressants and antitumor agents [16,17]. Numerous approaches are used for the synthesis of 1,3benzoxazine compounds using different solvents [18-20]. Among the approaches is the step-wise procedure which has recently gained considerable interest and more importantly tolerates various functional groups [21]. For this reason, the

Copolymerization of Tris(methoxyethoxy)vinyl Silane with N-Vinyl Pyrrolidone: Synthesis, Characterization, and Reactivity Relationships

International Journal of Polymer Science, 2015

Copolymer of tris(methoxyethoxy)vinyl silane (TMEVS) with N-vinyl pyrrolidone (NVP) was synthesiz... more Copolymer of tris(methoxyethoxy)vinyl silane (TMEVS) with N-vinyl pyrrolidone (NVP) was synthesized by free radical polymerization in dry benzene at 70°C using benzoyl peroxide (BPO) as initiator. The copolymer was characterized by viscometer, FTIR, and1H-NMR and its thermal properties were studied by DSC and TGA. The copolymer composition was determined by elemental analysis. The monomer reactivity ratios were calculated by linearization methods proposed by Fineman-Ross and Kelen-Tudos. The intersection method was proposed by Mayo-Lewis and nonlinear method was proposed by curve-fitting procedure. The microstructure of copolymer and sequence distribution of monomers in the copolymer were calculated by statistical method.