| With the development of the industry, water pollution by heavy metal ions further deteriorates the environment. So, it is nessary to develop a adsorbent which has low cost and hight adsorption capacity. Attapulgite (ATP) is a type of layered structure of hydrated Mg-Al silicate minerals with high surface area due to its intrinsic channel and nano-crystal, has application in adsorption on a large scale. This article studied APT as a good carrier, the PANI/ATP, ZVI/PANI/ATP and HTlc/ATP composite had been preparated to removal of metal ions in waste water, and some relevant mechanisms were studied. The main research works are as follows:1. ATP treated with ion exchange has good suspension property, PANI/ATP composite doped with HNO3was prepared by suspended static Polymerization, polyaniline was loaded uniformly on the surfaces of ATP. And these composites were used to adsorb Cr(VI) waste water. The effects of adsorption time, material ratio, inventory, temperature and pH value in the solution were investigated, kinetic and thermodynamic analysis were carried out that it’s a chemical adsorption process, chemical complexing effect played a leading role. The result shows that the material ratio of PANI/ATP was m(PANI:ATP)=1:0.75, the inventory was0.5g, adsorbed50mg L"1solution, the effect was99.60%after1h, the residual Cr(VI)was0.2mg L-1, the adsorption process was controlled by chemical coordination effect.2. PANI/ATP composite prepared by situ polymerization method doped with HC1and p-toluenesulfonic acid. Morphology of the composite was characterized by scanning electron microscopy (SEM).The effects of the mass ratio of the nanocom-posite to the aqueous solution, the quality of the PANI/ATP nanofiber composite, adsorptive time and temperature as well as pH value in the solution on the adsorptive performance of PANI/ATP composite were investigated, kinetic and thermodynamic analysis were carried out. The results reveal that the material ratio of m(PANI:P-TSA:ATP)=1:1:1, the PH value of2, the adsorption time was4h, then, the composite achieved the best adsorption capacity80.70mg g-1. The pseudo-second-order kinetic model could well confirm the experimental data and meaning that the adsorption process of Cr(VI) into the adsorbent was controlled by the chemical process, the thermodynamics of Cr(VI) adsorption on the composite follows the isothermal adsorption equations of Langmuir. The Langmuir model is valid for monolayer adsorption onto a surface containing a finite number of identical sites. 3. Polyaniline/Attapulgite (PANI/ATP) composite was well prepared in a solution of HNO3by static polymerization, in which the ZVI particles were successfully dispersed in the high viscosity of the PANI/ATP composite. Also, the effect of the anticorrosive and electrical conductivity of PANI on the surface of ZVI particles for removal of Cr(VI) are studied, settling the problem of poor-dispersing and easy-corroding of ZVI particles. The results show that the mass ratio of An, ZVI and ATP in this material was1:4:4, the adsorption capacity achieved86.56mg g-1which exhibited excellent adsorption capacity for removal of Cr(VI) from water, showing great potential as efficient adsorbent for water pollution arising from heavy metal ions on a large scale.4. The ATP loaded onto Mg-Al HT1c for removal of Ni(II) from wastewater was studied. The effect of adsorbing performance was investigated by pH value, inventory, adsorption time and temperature. The isothermal adsorption models and adsorption kinetics were also studied. The composite was characterized by SEM, FT-IR and XRD. The results shown that the composite had good recyclability, the adsorption process attributed to Langmuir monolayer adsorption and adsorption kinetics, which reflected physical diffusion and chemical reaction. As the pH value was at6.0and temperature at50℃, the adsorption capacity of the composite achieved80.94mg g-1. The mechanisms of adsorption process were also analyzed. |
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