| Red mud as solid waste in the production of Al2O3, to explore the comprehensive utilization of it has an important guiding significance.There were many research in wastewater treatment of red mud, and the effect of heavy metal wastewater treatment was good, but it was not easy to recycle made the modification of it became the key point of research.The research made up red mud ceramsite by red mud, fly ash, bentonite, pore forming agent and stabilizing agent firstly, the proportion of ingredients and firing condition of red mud ceramsite was determined by experiment; in the process of the preparation of red mud ceramsite, add nano Al2O3 further to made the modification of red mud ceramsite, select the optimal proportion of ingredients, and study factors of firing (preheating temperature, preheating time, calcination temperature, calcination time), do the comparison experiment about red mud ceramsite and nano modified red mud ceramsite, study the adsorption effect of wastewater of Sb(?), and furtherly demonstrates the feasibility of nano Al2O3 modified red mud ceramsite (hereinafter referred to as the modified red mud ceramsite) in heavy metal polluted waste water.Through theory, orthogonal ecperiments and single factor experiment, we can got the optimal proportion and firing conditions about red mud ceramsite and nano modified red mud ceramsite. The best proportion of red mud ceramsite was red mud:fly ash:bentonite:pore forming agent:stabilizing agent=30%:20%:10%:15%:5%, the optimum process conditions were drying temperature 105?, drying time 2h, preheating temperature 450?, preheating time 15min, calcination temperature 1000? and calcination time 25min. Under the condition, the removal rate of Sb(?) reached 84.25%. The adsorption performance was better after add nano Al2O3, the best ratio of nano modified red mud ceramsite was red mud:fly ash:bentonite:pore forming agent:stabilizing agent:nano A1203=30%:20%:10%:15%:5%:1%, the optimum technological conditions were the same with the red mud ceramsite. Under the condition, the removal rate of Sb(?) can reached 95.76%.Study the static adsorption property of nano modified red mud ceramsite for Sb(?) and Cd(?) waste water, and respectively discussed the effect of nano modified red mud ceramsite's adsorption on Sb(?) and Cd(?) by the initial pH value, the concentration of solution, additive quantity of adsorbent, adsorption time, temperature. The experimental data of static adsorption about Sb(?) and Cd(?) showed that the quasi secondary dynamics model and Langmuir isotherm equation were suitable for adsorption process, the adsorption reaction is exothermic reaction.Study the dynamic adsorption property of nano modified red mud ceramsite for Sb(?) and Cd(?) waste water, respectively discussed the column height, initial concentration of Sb(?) and Cd(?), velocity of solution. The study showed that with higher of adsorption column, smaller of the initial concentration of Sb(?) and Cd(?), smaller of flow velocity, the retention time of Sb(?) and Cd(?) in adsorption column is longer, more conducive to the removal of Sb(?) and Cd(?). Column height can fitting BDST model well, concentration of solution can fitting Thomas model well.Through the instruments analysis of SEM?FTIR and XRD, studied the adsorption mechanism of Sb(?) and Cd(?) in simulated wastewater.Results showed that:the modified red mud ceramsite is porous,the specific surface area is large,-OH,C-O groups were involved in the heavy ions adsorption process, formed new oxide phase, the adsorption process contained a combination of physical adsorption and chemical adsorption.The results of regeneration experiment showed that the modified red mud ceramsite can realize recycling through a variety of desorption agent, nitric acid solution works best among them; leaching toxicity studies showed that the modified red mud ceramsite after adsorption of heavy metals does not belong to dangerous solid waste, it will not cause secondary pollution. |
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