The Preparation Of Composite Adsorbent And Its Adsorption Behavior For Metal Ions

In recent years, due to the rapid development of industrialization and urbanization, water heavy metal pollution in environmental pollution has become a problem that can not be ignored.Excessive heavy metal ions in aquatic which eventually enters people's body because of the aquatic food chain will be the enrichment heavy metals of water, lead to serious toxic effects on people. How to decreasing heavy metal in water have already become more concerned about among people, more in-depth research and sophisticated is adsorption in a number of processing methods for reducing heavy metals. In different adsorbents, since clay, agricultural and forestry waste are countless and lower price compared with other types of adsorbents, getting people's attention. In this thesis, based on summarizing methods of water treatment, the type of adsorbent,adsorption thermodynamics and kinetics, do the following work:?1? Using NaBH₄ reduction of FeCl₃ to prepare the peanut/nZVI compound material.compound material was characterized by means of FT-IR, TEM and XRD. After Cu²⁺, Pb²⁺ and Ni²⁺were adsorbed, the influences of the pH, oscillation time, initial concentration for absorbing capacity of Cu²⁺, Pb²⁺ and Ni²⁺ were investigated. The results show that: the temperature for293 K, adsorbent dosage is 10 mg, pH of ion solution is 5 and the oscillation time is 120 min, the maximum adsorption capacity of the adsorbent for Cu²⁺and Ni²⁺is 230.41mg/g, 288.18mg/g,respectively. At 293 K, adsorbent dosage is 10 mg, pH of the ion solution is 5 and the oscillation time is 40 min, the maximum adsorption capacity of the adsorbent for Pb²⁺ is 628.93mg/g; three ion adsorption capacity is higher than peanut shells alone under the same conditions. Linear fitting results of isotherm models are Langmuir equation constants great higher than others, so Langmuir equation can describe the adsorption isotherm well. The results of adsorption kinetics show that adsorption kinetics belong to pseudo-second order kinetics. Thermody- namic calculations show that the adsorption occurs is spontaneous.?2? Getting BTA modified palygorskite through the reaction between alkylation?KH560?palygorskite and benzotriazole, then characterize BTA modified palygorskite use various methods, such as FT-IR, EA, SEM and TGA. The results of adsorption experiments for Pb²⁺show that: temperature at 313 K, 10 mg of BTA modified palygorskite added to Pb²⁺ solution pH of 5 and oscillated after 60 min, the maximum adsorption capacity of adsorbent for Pb²⁺is 50.61mg/g. Adsorption process can well described by the Langmuir isothermal adsorption model; the adsorbent kinetics of Pb²⁺showed that the kinetic of BTA modified palygorskite adsorb Pb²⁺belong to pseudo-second order kinetics.?3? Palygorskite/poly?allylthiourea-acrylamide? composite prepared by situ polymerization method. Respectively, FT-IR, EA, SEM and TGA were used to characterize the compound, and testing its adsorption properties for Pb²⁺. The results of adsorb experiment for Pb²⁺ show that: at room temperature, 10 mg of this composite material added to Pb²⁺ solution that initial concentration is 50 mg/L and pH is 5, then shaking after 30 min, the maximum adsorption capacity of Pb²⁺ is 21.5mg·g^-1. Adsorption capacity of adsorbent for Pb²⁺ increases with the solution temperature increases, Langmuir isotherm model can describe the adsorption process at different temperature, meanwhile, adsorption kinetics of palygorskite/ poly?allylthiourea-acrylamide? adsorpt Pb²⁺ belong to pseudo-second order kinetics.