Preparation Andapplication Of Metal-loaded Carbonaceous Adsorbents

With the development of wastewater, sewage sludge was produced in an ever increasingamount. Without proper treatment and disposal, sewage sludge would cause a secondarypollution problem, because it is rich in organic materials, and substantial amout of dangeroussubstances, as well as heavy metals and pathogenic germs. Materialization of sewage sludgeis becoming more and more important way of treatment sewage sludge. Compared withtraditional electrical heating, preparing sludge adsorbent by microwave-induced pyrolysis hasthe advantage of high effective, high-speed. Adsorbent prepared through this technology hasvery good effect on treating of dye wastewater, and has a good application prospect.This paper was focus on the preparation of activated sludge adsorbent, which was usedcity sewage treatment plant sludge as raw material, H2SO4、ZnCl2、NaOH、H3PO4as activator,sludge adsorbent iodine value was measured through a single factor and orthogonalexperiment investigation. It was shown that the optimum microwave power was560W,microwave time3min, concentration of activator40%, and solid-to-liquid ratio1:1.5with thebest adsorption values about360.43mg/g.Muffle furnace and microwave irradiation was used to activate the sludge adsorbent,with sodium hydroxide as activator, copper nitrate and ferric nitrate as dip liquid. Effect ofimpregnation liquid concentration, drying time, microwave power (roasting temperature),irradiation time, and roasting time to the adsorption value of methylene blue though a singlefactor experiment were investigated. By means of ICP, SEM, FTIR, specific surface area andpore structure analyses, thermogravimetric analysis (TGA), ultraviolet visible light spectrumtests, the metal-loaded absorbents were characterized, the decolorization rate of methylenesimulation wastewater and COD removal, as well as the adsorption kinetics were alsoidentified. It was found that the decolirazation to methylene of loaded adsorbent bymicrowave was better than that prepared in muffle furnace, the optimum drying time was6h,impregnation liquid volume18mL, irradiation time3min, microwave power480w, the best absorption of methylene blue value57.23mg/g, specific surface area6.7218m2/g, methylorange decolorization rate is60.33%, COD removal rate51.23%, microporosity17.79%forthe copper loaded absorbent, but as the iron loaded adsorbent, impregnation liquid product is20mL, irradiation time1min, and microwave power640W, the absorption value ofmethylene blue about56.15mg/g, surface area9.0558m2/g, methyl orange decolorization rate68.12%, COD removal rate of simulated wate55.32%, microporosity19.82%. Adsorptionconforms to Langmuir isotherm equation and Freundlich isothermal equation.