Method for removing Congo red through adsorption of bean dreg-hydrocalumite composite material
Technical Field
The invention belongs to the technical field of functional materials and water treatment, and particularly relates to a method for removing Congo red by adsorbing bean dregs-hydrocalumite composite materials.
Background
The bean dregs are main by-products in the processing process of bean products, and the yield of wet bean dregs in China is more than 2000 million tons every year. The wet bean dregs have high protein content, high water content, easy decay and deterioration and difficult preservation, most of the bean dregs are still directly discarded, and the environmental pollution and the resource waste are caused. Therefore, the high-value utilization of the bean dregs becomes a key technical problem which is urgently needed to be solved by the bean product processing industry.
The bean dregs have larger specific surface area and abundant pore structures, contain active functional groups such as hydroxyl, carboxyl and the like, and have the potential of being used as a biomass adsorbent. In recent years, the literature reports a series of modification treatment methods of the bean dregs and application performance of the bean dregs in the field of adsorption. However, compared with inorganic high-efficiency adsorbing materials such as zeolite, activated carbon and hydrotalcite, the adsorbing capacity of the bean dregs is relatively small, and the large-scale application of the bean dregs as the adsorbing materials is limited.
Therefore, the bean dregs are used as raw materials to develop the composite material with high-efficiency adsorption performance so as to solve the problem that the adsorption capacity of the bean dregs is relatively small, and the composite material has important significance for realizing high-value utilization of the bean dregs.
Disclosure of Invention
The invention aims to provide a method for removing Congo red by adsorbing bean dregs-hydrocalumite composite materials.
The method for removing Congo red by bean dregs-hydrocalumite composite material adsorption provided by the invention takes the bean dregs-hydrocalumite composite material as an adsorbent to remove Congo red in water by adsorption, and is characterized in that the preparation process of the bean dregs-hydrocalumite composite material comprises the following steps:
(1) mixing soluble calcium salt and water to obtain salt solution, and adding NaAlO2、NaOH、Na2CO3Mixing with water to prepare an alkali solution;
(2) dispersing bean dregs in water, heating to 50-90 ℃, adding a salt solution and an alkali solution, continuously stirring for reaction for 0.5-3 h, stopping stirring, crystallizing for 10-25 h at 70-100 ℃, dehydrating and drying precipitates obtained by the reaction, and obtaining the bean dregs-hydrocalumite composite material.
The steps are[ Ca ] of calcium salt in step (1)2+]=1~3 mol/L。
In a further aspect of the present invention,
n(NaAlO2)/n(Ca2+)=0.2~0.5;
n(NaOH)/n(Ca2+)=0.8~1.0;
n(Na2CO3)/n(Ca2+)= 0.4~0.6。
the bean dregs and NaAlO2The mass ratio of (A) to (B) is 0.5-1.5: 1.
the soluble calcium salt is calcium chloride, calcium sulfate or calcium nitrate.
The addition amount of the bean dregs-hydrocalumite composite material is 0.5-3 g/L.
The initial concentration of the Congo red is 10-1000 mg/L.
Compared with the prior art, the technical scheme provided by the invention has the following advantages: (1) the related bean dregs-hydrocalumite composite material has higher removal rate and adsorption capacity to Congo red in water, and the adsorption performance is superior to that of single hydrocalumite or bean dregs, so that good synergistic effect is embodied; (2) the bean dregs-hydrocalumite composite material prepared by taking the bean dregs as the raw material has low production cost; (3) provides a new method for high-value utilization of the bean dregs.
Detailed Description
The following provides a more detailed description of the present invention. The above and other objects, features and advantages of the present invention will be apparent to those skilled in the art from the detailed description of the present invention.
Example 1
Preparation of an adsorbing material: dissolving 0.1 mol of calcium chloride in water to prepare 50 mL of salt solution, wherein [ Ca2+]=2.0 mol/L; 0.025 mol of NaAlO20.09 mol of NaOH and 0.05 mol of Na2CO3Dissolving in water to prepare 50 mL of alkaline solution, wherein n (NaAlO)2)/n(Ca2+)=0.25,n(NaOH)/n(Ca2+)=0.9,n(Na2CO3)/n(Ca2+) = 0.5; dispersing 2.08 g bean dregs in water, and maintaining at constant temperature of 80 deg.CAdding a salt solution and an alkali solution under the condition of continuous stirring, and reacting for 2 hours; stopping stirring, and crystallizing at 80 ℃ for 17 h; filtering, washing, drying and crushing to obtain the bean dregs-hydrocalumite composite material.
Example 2
Preparation of an adsorbing material: 0.1 mol of calcium sulfate was dissolved in water to prepare 100 mL of a salt solution, wherein [ Ca ]2+]=1.0 mol/L; 0.05 mol of NaAlO20.08 mol of NaOH and 0.04 mol of Na2CO3Dissolving in water to prepare 100 mL of alkaline solution, wherein n (NaAlO)2)/n(Ca2+)=0.5,n(NaOH)/n(Ca2+)=0.8,n(Na2CO3)/n(Ca2+) = 0.4; dispersing 5.02 g of bean dregs in water, adding a salt solution and an alkali solution under the conditions of constant temperature of 60 ℃ and continuous stirring, and reacting for 3 hours; stopping stirring, and crystallizing at 100 deg.C for 10 hr; filtering, washing, drying and crushing to obtain the bean dregs-hydrocalumite composite material.
Example 3
Preparation of an adsorbing material: 0.1 mol of calcium nitrate was dissolved in water to prepare 40 mL of a salt solution in which [ Ca ]2+]=2.5 mol/L; 0.02 mol of NaAlO20.1 mol of NaOH and 0.06 mol of Na2CO3Dissolving in water to prepare 40 mL of alkaline solution, wherein n (NaAlO)2)/n(Ca2+)=0.2,n(NaOH)/n(Ca2+)=1.0,n(Na2CO3)/n(Ca2+) = 0.6; dispersing 2.25 g of bean dregs in water, adding a salt solution and an alkali solution under the conditions of constant temperature of 90 ℃ and continuous stirring, and reacting for 0.5 h; stopping stirring, and crystallizing at 70 deg.C for 25 h; filtering, washing, drying and crushing to obtain the bean dregs-hydrocalumite composite material.
Example 4
Adsorption of congo red in water: adding 1.6 g of the bean dregs-hydrocalumite composite material prepared in the example 1 into 1L of an aqueous solution with the Congo red concentration of 800 mg/L, and stirring and adsorbing for 2 h; after centrifugal separation, spectrophotometry is adopted for sampling and detection, the adsorption rate of Congo red in water is 95.5%, and the adsorption capacity is 477.5 mg/g.
Example 5
Adsorption of congo red in water: adding 0.5 g of the bean dregs-hydrocalumite composite material prepared in the example 2 into 1L of an aqueous solution with the Congo red concentration of 200 mg/L, and stirring and adsorbing for 1 h; after centrifugal separation, spectrophotometry is adopted for sampling detection, the adsorption rate of Congo red in water is 99.2%, and the adsorption capacity is 396.8 mg/g.
Example 6
Adsorption of congo red in water: 2.5 g of the bean dregs-hydrocalumite composite material prepared in the example 3 is added into 1L of an aqueous solution with the Congo red concentration of 1000 mg/L, and stirred and adsorbed for 2 hours; after centrifugal separation, the Congo red is sampled and detected by a spectrophotometry method, the adsorption rate of the Congo red in water is 98.5%, and the adsorption capacity is 394 mg/g.
Comparative example 1
Hydrocalumite was prepared in the same manner as in example 1, except that the bean dregs were not added; the prepared hydrocalumite is used for adsorbing and removing Congo red in water, and the adsorption condition and the detection method are the same as those in the embodiment 4; the results show that the adsorption rate of the hydrocalumite on the Congo red in water is 65.9 percent, and the adsorption capacity is 329.5 mg/g.
Comparative example 2
The bean dregs are used for adsorbing and removing Congo red in water, and the adsorption condition and the detection method are the same as those in the embodiment 4; the result shows that the adsorption rate of the bean dregs to the Congo red in the water is 50.6 percent, and the adsorption capacity is 253 mg/g.
According to the results of the examples 4-6 and the comparative examples 1 and 2, the okara-hydrocalumite composite material has high removal rate and adsorption capacity for congo red in water, the adsorption performance of the okara-hydrocalumite composite material is superior to that of single hydrocalumite or okara, and good synergistic effect is shown among the components. The bean dregs-hydrocalumite composite material takes the bean dregs as one of the raw materials, and the production cost is low. Based on the characteristics, the technical scheme provided by the invention provides a new method for high-value utilization of the bean dregs and treatment of wastewater containing Congo red.
It should be understood that although the present invention has been clearly illustrated by the foregoing examples, various changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the invention, and it is intended to cover all such changes and modifications as fall within the scope of the appended claims.