Study On Heavy Metal Absorption By Modified Montmorillonite

This topic selects montmorillonite clay minerals to the modification, develops environmentally friendly mineral adsorption materials, aims to solve environmental pollution from the main industrial waste water containing heavy metals, at the same time with experimental basis for montmorillonite clay minerals such as the environment application. The subject study has important theoretical significance and practical application value.Papers on montmorillonite sodium modification, organic modification and complexation modification and its processing including the preparation conditions Cu, Pb, Zn, Cd and so on many kinds of heavy metal ions adsorption of phenol and industrial waste water conditions in the system the research, the use of XRD, DTA/TG, SEM and analysis of the test means characterized, studies the modified montmorillonite to a variety of different concentrations of heavy metal ion adsorption performance of industrial waste water, and discusses the modified montmorillonite adsorption wastewater of heavy metal ion in adsorption dynamics equation and the adsorption mechanism.The main research results are as follows:1.Montmorillonite modified preparation research:(1)To montmorillonite sodium has modified, organic modification and complexation modification, sodium modification of test showed purification montmorillonite and the concentration of5%NaOH solid-liquid ratio for solution, PH=5.6, under60℃mixing1h, after80℃oven centrifugal in dry grinding get sodium modified montmorillonite, among of which, Pb2+,Cu2+, and Zn2+,Cd2+adsorption rate were99.2%,92.8%,99.5%and99.3%.(2) Organic modified montmorillonite of the best preparation conditions is: a100mesh fineness of sodium of montmorillonite join0.8times the CEC organic modifier (CTMAB), than for solid and liquid, PH=5.6, the temperature of60℃under constant temperature mixing1h, centrifugal in80℃oven after dry grinding get after CTMAB-Mont, Cu2+, Pb2+, Zn2+and Cd2+adsorption rate were87.81%,98.2%,98.4%,98.1%.(3)Complexation modified montmorillonite is the best preparation conditions: say take Ng of sodium montmorillonite, join N*0.0422g (0.8CEC) organic modifier CTMAB, solid-liquid ratio is1:10, constant temperature60℃water bath mixing1.5h, join TEPA (NTEPA: NCTMAB=1:1), in80℃oven drying under after grinding TEPA get-Mont, Cu2+, Pb2+, and Zn2+, Cd2adsorption rate respectively were88.5%,99.1%,99.2%,98.9%.2.The characterization of modified montmorillonite:(1)Through the soils, sodium to the soil, complexation modification of XRD map soil analysis, d001were1.24349nm and1.23339nm and2.36298nm, d001layer with sodium HuaJian small spacing, organic inserted layer and increase after that CTMAB replace sodium based montmorillonite of sodium ions and the formation of the complex, organic cation make crystal layer spacing increase, and according to the cetyl three methyl brominated ammonium chain long for2.6nm judgment, carbon chain in intercropping layer oblique arrangement, results and expected results are consistent, achieve mesoporous level.(2)Sodium in200℃below zero is because of the soil sample of adsorption of free water and layers have been caused by water, and in590℃-650℃of weightlessness is because between the grid collapse caused by between layers of the collapse; For organic modified montmorillonite and complexation modified montmorillonite speaking, in200℃the following almost no weightlessness, in240℃390℃there is a big gap between the weightiessness, this is into the montmorillonite CTMAB decomposition of the layers caused; Without the modified montmorillonite in100°C have a heat valley, mainly is lost between layers of water and adsorption of free water, in850℃(?) decomposition heat release results(3)The soils, sodium modified soil, organic soil microstructurc of modification, the figure is visible through sodium modified soil layer of flake’s like stack, dispersivity is the soils of good, CTMAB and montmorillonite combined with the modified by the complex in the soil sample surface more loose, soil samples from hydrophilic into the lipophilic, TEPA with surface active agent of the water-based generated scanty water distribution can be key in the outer surface of the montmorillonite, making the montmorillonite of hydrophobic enhanced.3.The discussion on modified montmorillonite to heavy metal absorption mechanism:Organic modified montmorillonite and composite modified montmorillonite Cu2+,Pb2+,Zn2+and Cd2+adsorption, studies the organic modified montmorillonite and composite modified montmorillonite adsorption thermodynamics and kinetics and the heavy metal particles internal diffusion equations and the isothermal adsorption equation, the isothermal adsorption Cu2+,Pb2+, Zn2+, Cd2+with Freundlich equation curve fitting is best, organic modified montmorillonite Cu2+, Pb2+, and Zn2+, Cd2+ion of saturated adsorption were19.8mg/g,10.8mg/g,16.8mg/g,14.6mg/g, complexation modified montmorillonite of four ion of saturated adsorption were22.3mg/g,21.8mg/g,19.4mg/g,16.5mg/g, complexation modified montmorillonite adsorption effect to better than organic modified montmorillonite.