Dar-Ren Ji

This study examines the applicability of the processes of sedimentation (SED), surface degreasing (SDG), sand filtration (SF), ozonation (OZ), UV irradiation and membrane separation (MS) for the recycling and reutilization of car wash wastewater (denoted as c-water). At the car wash station, the c-water is collected in an open-channel that flows into a settling tank. The grease on the surface of water in the settling tank (called as SED-water) is removed periodically via SDG. The major contaminants of SED-water are surfactants, inorganic compounds, organic compounds and grease of high concentration. The surface degreased SED-water after the settling tank located in the car wash station (noted as SDG-water) was treated firstly via SF for the removal of some suspended solid and grease. Three sand sizes (0.355-0.425, 0.425-0.6 and 0.6-0.85 mm) were tested. It followed with the OZ. UV irradiation was applied to enhance the effectiveness of OZ. As for the MS, membranes with six pore size...

In this study, vinyl chloride (VC), the primary material for manufacturing polyvinyl chloride (PVC), is decomposed via catalytic oxidation (C-OX) using Pt/γ-Al2O3 catalyst. The effects of related major factors such as reaction temperature (T) and gas hourly space velocity on the conversion of VC (X) were examined. The values of T for achieving conversions of 50% and 90% are 504 and 580 K with C-OX, respectively, whereas those without Pt/γ-Al2O3 (i.e., thermal oxidation, T-OX) are 900 and 983 K, respectively, thus indicating that C-OX significantly reduces T for effective oxidation of VC to form CO2, HCl, and Cl2 when compared with T-OX. The mineralizations of carbon in VC to form CO2 are 75.5% and 38% for C-OX and T-OX, respectively, at 90% X. The conversions of chlorine atom in 1,2-dichloroenane (DCEA) to Cl in HCl and Cl2 are approximately 42% and 50.8% for C-OX and T-OX, respectively, at 90% X. These results indicate that the Pt/γ-Al2O3 catalyst exhibits remarkable performance fo...

Dimethyl phthalate (DMP) was treated via wet oxygen oxidation process (WOP). The decomposition efficiencyηDMPof DMP and mineralization efficiencyηTOCof total organic carbons were measured to evaluate the effects of operation parameters on the performance of WOP. The results revealed that reaction temperatureTis the most affecting factor, with a higherToffering higherηDMPandηTOCas expected. TheηDMPincreases as rotating speed increases from 300 to 500 rpm with stirring enhancement of gas liquid mass transfer. However, it exhibits reduction effect at 700 rpm due to purging of dissolved oxygen by overstirring. Regarding the effects of pressurePT, a higherPTprovides more oxygen for the forward reaction with DMP, while overhighPTincreases the absorption of gaseous products such as CO2and decomposes short-chain hydrocarbon fragments back into the solution thus hindering the forward reaction. For the testedPTof 2.41 to 3.45 MPa, the results indicated that 2.41 MPa is appropriate. A longer r...

Magnetic polyvinyl alcohol adsorbent M-PVAL was employed to remove and concentrate dimethyl phthalate DMP. The M-PVAL was prepared after sequential syntheses of magnetic Fe3O4(M) and polyvinyl acetate (M-PVAC). The saturated magnetizations of M, M-PVAC, and M-PVAL are 57.2, 26.0, and 43.2 emu g−1with superparamagnetism, respectively. The average size of M-PVAL by number is 0.75 μm in micro size. Adsorption experiments include three cases: (1) adjustment of initial pH (pH0) of solution to 5, (2) no adjustment of pH0with value in 6.04–6.64, and (3) adjusted pH0= 7. The corresponding saturated amounts of adsorption of unimolecular layer of Langmuir isotherm are 4.01, 5.21, and 4.22 mg g−1, respectively. Values of heterogeneity factor of Freundlich isotherm are 2.59, 2.19, and 2.59 which are greater than 1, revealing the favorable adsorption of DMP/M-PVAL system. Values of adsorption activation energy per mole of Dubinin-Radushkevich isotherm are, respectively, of low values of 7.04, 6....

ABSTRACT The catalytic oxidation of 1,2-dichloroethane (DCEA) using Pt/Al2O3 with and without ozone (noted as OZCO and COXI, respectively) was carried considering the key operation parameters of reaction temperature (T), space velocity (SV) of catalyst and inlet concentration of O3 ( ). The results indicate that OZCO decreases the reaction temperature and enhances the conversion of DCEA (X) to form CO2, HCl and Cl2 comparing with COXI. At 200 ppmv and 125,000 1/h SV, 50% and 90% conversions of DCEA via OZCO are achieved at 430 and 610 K, while those via COXI are reached at 582 or 640 K, respectively. The mineralization of carbon in DCEA to form CO2 ( ) with ozone (e.g. 90% at 620 K) is systematically higher than that without ozone (e.g. 60% at 620 K). The conversions of chlorine atom in DCEA to Cl in HCl and Cl2 are about 62.5% and 37% for OZCO at 625 K with ∼100% , which are higher than 51.5% and 10.3% for COXI at 645 K with 97% , respectively. Thus the conversions of carbon and chlorine are near completion, indicating the effectiveness of OZCO for destructing the chlorine-containing pollutant of DCEA.

Production of jatropha-ester (JO-ester) from jatropha oil (JO) under sequential direct-ultrasonic irradiation (UI) with auto-induced temperature rise followed by adding a mixture of methanol/sulfuric-acid catalyst (M/C) dose between high temperature intervals was studied. Comparisons with various doses of 5, 10, 16.6 and 25 mL at different temperature intervals of 108.9 to 120 °C, 100 to 120 °C, 85 to 120 °C and 75 to 120 °C respectively were performed. System parameters examined include: esterification times (tE) for UI, settling time (tS) after esterification and temperature (T). Properties of acid value (AV), iodine value (IV), kinematic viscosity (KV), density (ρLO) and water content (mw) of JO and JO-ester product were measured. The esterification conversion efficiencies (η) were determined and assessed. An η of 99.35% was obtained at temperature interval of 108.9 to 120 °C with 5 mL per dose for 20 doses and tE of 167.39 min (denoted as Process U120-5), which is slightly higher than η of 98.87% at temperature interval of 75 to 120 °C with 25 mL per dose for 4 doses and tE of 108.79 min (noted as Process U120-25). The JO-ester obtained via sequential UI with adding doses of 5 mL possess AV of 0.24 mg KOH/g, IV of 124.77 g I2/100 g, KV of 9.89 mm2/s, ρLO of 901.73 kg/m3 and mw of 0.3 wt.% showing that sequential UI and dose at higher temperature interval can give higher reduction of AV compared with 36.56 mg KOH/g of original oil. The effects of tS and tE on AV are of minor and moderate importance, respectively. The combined effects of auto-induced temperature-rise of UI and temperature higher than boiling point of methanol used improve the mixing and esterification extent.

ABSTRACT Auto-induced temperature-rise effects of ultrasonic irradiation (UI) on the esterification performance of jatropha oil (JO) were studied. Comparisons with other methods of mechanical mixing (MM) and hand shaking mixing were made. Major system parameters examined include: esterification time (tE), settling time (tS) after esterification and temperature. Properties of acid value (AV), iodine value (IV), kinematic viscosity (KV) and density of JO and ester product were measured. The esterification conversion efficiencies (η) were determined and assessed. Sulfuric acid was used to catalyze the esterification using methyl alcohol. For esterification without temperature control, η at tE = 10 and 30 min for UI of 56.73 and 83.23% are much higher than those for MM of 36.76 and 42.48%, respectively. At tE = 10 min, the jatropha oil esters produced via UI and MM respectively possess AV of 15.82 and 23.12 mg KOH/g, IV of 111.49 and 113.22 g I2/100 g, KV of 22.41 and 22.51 mm2/s and density of 913.8 and 913.58 kg/m3, showing that UI is much better than MM in enhancing the reduction of AV. The tE exhibits more vigorous effect on AV for UI than MM. The UI offers auto-induced temperature-rise, improving the mixing and esterification extents.

In this study, a high-gravity rotating packed bed (HGRPB or HG) was used as a catalytic ozonation (Cat-OZ) reactor to decompose phenol. The operation of HGRPB system was carried out in a semi-batch apparatus which combines two major parts, namely the ...

This study examined the desorption of copper ions, which were adsorbed on the magnetic polymer adsorbent (MPA) of polyvinyl acetate-iminodiacetic acid (M-PVAC-IDA), by ethylenediaminetetraacetic acid (EDTA). Stage-wise desorptions were applied to remove ...

This study examines the applicability of the processes of sedimentation (SED), surface degreasing (SDG), sand filtration (SF), ozonation (OZ), UV irradiation and membrane separation (MS) for the recycling and reutilization of car wash wastewater (denoted as c-water). At the car wash station, the c-water is collected in an open-channel that flows into a settling tank. The grease on the surface