Study On Surface Modified Chrysotile And Its Adsoption Property Of Copper Ions

Chrysotile is a typical tubular phyllosilicate constituted by repeating sheets of basic Mg(OH)2 and acidic SiO2 groups. Chrysotile asbestos have certain adsorption performance and modification basic because of special structure:a large specific surface area, unsaturated bonds and surface hydroxyl. Currently, although there are few reports about the use of serpentine group minerals to deal with wastewater containing copper, these researches are more confined to a single test on adsorption effect, lacking of theoretical studies and systematism. This article focuses on the above questions, selecting a silane coupling agentγ-APS containing amino group as modified resin, treating chrysotile in water phase with single experimental condition factor, then it analyzes the modification mechanism. Adsorption behavior and dynamics are studied systematically. These results provide theory basis for application of chrysotile in wastewater treatment. Major conclusions and innovations of this thesis are obtained as follows:(1) Chrysotile can be modified by a silane couping agent namedγ-APS in the water system. The analysis test results reveal that the coupling agent has been grafted onto the chrysotile surface successfully.(2) Main factors of adsorption by Cu2+ on chrysotile are temperature, pH value, and initial concentration of copper ions. The capacity that Cu2+ ions adsorb on modified chrysotile has been significantly increased. The adsorption increased 0.235mmol/g, with removal rate of 33%.(3) The adsorption of Cu2+ on modified chrysotile can coincide with the pseudo-second order reaction kinetics model. The modification could enhance the adsorption average reaction rate and the initial reaction rate. The effect ways of main factors, like temperature, pH value and initial concentration, on the adsorption kinetics of modified chrysotile are also explained.(4) The initial concentration provides the necessary driving force to overcome the resistance to the mass transfer of copper between aqueous phase and the solid phase. The main mechanism is due to the ion exchange between copper ions and the H+ of the external hydroxyl groups of the inorganic matrix. The dipole force and hydrogen bonding force are the main driving forces. After modification, copper ions chelating with amidogen is the another mechanism beside ions exchange.