Studies On The Heavy Metal Ion Adsorption Of The Modification Of Chaff Cellulose

With the rapid development of modern science and technology, industrial pollution,especially the discharge of heavy metal waste water, has become the urgent problem recently. So how to reduce the damage of heavy metal wastewater to water and soil have been the major tasks of the environmental protector.Nowadays, a number of technologies have been used to remove heavy metals from aqueous solutions including chemical precipitation, coagulation and flocculation, electro catalytic oxidation, ion-exchange, membrane separation technique and adsorption. Biosorption has the advantages for its cheap and available substrate material, extensive sources, effective and environmental adsorption. The agriculture and forestry waste thus has become the focus materials in substrate material.Chaff, one of the agriculture and forestry waste, was firstly smashed and basified. Then through carboxymethylation、esterification、amination and epoxidation、iminodiacetic acid, two efficient metal adsorbents are prepared. The structure about the former and the latter of the modified chaff were characterized by FTIR. And through the adsorption of Cu²⁺ waste water, the optimal adsorption capacity of IDACC and CMCA were studied, including pH value, adsorption time and initial concentration. The adsorption kinetics was investigated, and the adsorption isotherm was determined. The kinetic experimental data of both IDACC and CMCA are correlated with pseudo-second-order kinetic model. The control steps of the reaction rate are chemical reaction. The isotherms data of IDACC and CMCA fit well to the Langmuir model. The adsorbtion behavior of IDACC and CMCA for Cu²⁺ belongs to the monolayer adsorption.On the basis of Cu²⁺ adsorption experiment, we conduct adsorption experiments about actual wastewater using IDACC and CMCA to examine the feasible of the modified materials in applications. Experimental results show that the effects of pH value on adsorption rate is not obvious. There is the optimal pH value to treatment the wastewater. The pH value is 8 for CMCA and 6-7 for IDACC. When the IDACC dosing is 2g, all of the heavy metal can achieve the wastewater discharge standard. When the CMCA dosing is 0.7g, all of the heavy metal can achieve the wastewater discharge standard, except Cd²⁺. CMCA and IDACC have two completely different adsorption heating effects. The adsorption process of CMCA is exothermic process however the adsorption process of IDACC is endothermic process. After five times regeneration experiment, IDACC performs well with the removal rate more than 78%. The regeneration performance of CMCA is no better than that of IDACC, especially the adsorption of Cd²⁺. So, IDACC is more suitable in actual application.