Preparation And Adsorption Properties Of Mg, Al, Cu, Mg, Al Hydrotalcite Study

With economic development, more and more pesticides and dyes used in agricultural and industrial production,the resulting environmental pollution problems are more serious,so finding a safe and efficient low-cost and no secondary pollution adsorbent markedly effective urgent.Hydrotalcite has a unique layered structure,porous structure,exchangeable interlayer anions and composite metal oxide structure, memory effect, good crystallinity,large surface area,which has become a research hotspot in the treatment of water pollution.This paper based on analyzing the preparation of LDHs and the problems of application, We systematically investigated the preparation method of Mg/Al-CO32-and Cu/Mg/Al-CO32-, and then studied on adsorption on 2,4-Dichlorophenoxyacetic acid and Eriochrome blue black R.The parper is composed of the following partes:1.Preparation and characterization of Mg/Al-LDH and Mg/Al-LDOUsing Mg(NO3)2-6H2O,Al(NO3)3-9H2O,NaOH and Na2CO3 as raw material,a series of hydrotalcite precursor Mg/Al-C032- were prepared by microwave and hydrothermal method under different conditions.When calcined the precursors at 500℃,products changed into mixed metal oxides (LDO).The two products were characterized by FT-IR,XRD,TEM,ICPand so on.2. Preparation and characterization of Cu/Mg/Al-LDH and Cu/Mg/Al-LDOUsing Mg(NO3)2-6H2O, Al(NO3)3-9H2O,Cu(NO3)2-3H2O, NaOH and Na2CO3 as raw material,a series of hydrotalcite precursor Mg/Al/Cu-CO32- were prepared by microwave and hydrothermal method under different conditions.When calcined the precursors at 500℃, products changed into mixed metal oxides (LDO).The products were also characterized as above.The results show that:The products prepared according to two methods have the characteristics of uniform particle,small particle size,large specific surface.The layered structure were destroyed by calcination at 500℃,but the specific surface area and pore volume has significantly increased.3. Study adsorption properties of EBR on LDH and mixed oxidesAs more and more dyes are used in production,dyes pollution has caused serious environmental problems. Therefore,in this part,we first introduced the adsorbent's research status,then examined the adsorption situation of various dyes.Among them, the sample adsorption on the Eriochrome blue black R(EBR) has the highest rate. Different from the adsorption of 2,4-D on hydrotalcite precursor, chrome blue-black R was highly adsorbed on LDH.Under the same conditions mixed oxides almost completely adsorbed EBR in a short time. Experiment proved that metal oxides obtained from LDH can be good adsorbent for low concentration of dye wastewater. 4. Study adsorption properties of 2,4-D on LDH and mixed oxidesWe studied the adsorption properties of 2,4-Dichlorophenoxyacetic acid(2,4-D) on LDH and LDO by equilibrium adsorption.Experiments show that the adsorption efficiency of 2,4-D on LDHs is very low,while the mixed oxides on the adsorption of 2,4-D is much higher,the adsorption efficiency can reach 90%, and the adsorption curve was fitted Langemuir isotherm.