Study On The Preparation Of Absorbent From Sewage Sludge And Rice Husk And Its Application In Dye Wastewater Treatment

Aiming at growing amount of sewage sludge and rice husk and more and moretighten treatment restriction they face and also non-biodegradable dye wastewater, thispaper propose to use fixed carbon in sewage sludge and rice husk to make them intoabsorbent and apply it in dye wastewater treatment.ZnCl2was chosen as the best activator and1:1was the best sludge to husk ratio.Absorbent with the best absorption capacity can be prepared when ZnCl2concentration isabout6mol/L, solid-to-liquid ratio reaches1:2, and preparation temperature is at600℃.BET test showed the absorbent has a high surface area of460.5m2/g. TGA proved ZnCl2can bring more weight loss but improve carbon content at the same time. SEM test gavea clear picture of pore structure in the absorbe nt. FTIR analysis indicated that theabsorbent has many functional structures such as amino, sulfo and phosphate.Application of the absorbent prepared in dye wastewater treatment was also studied.Absorption quantities of methylene blue and reactive brilliant red increase with initialdye concentration and can reach93.2mg/g and87.2mg/g separately when initial dyeconcentration is70mg/L. Absorption quantities of both dyes also increase withtemperature but keep steady when salinity changes. Solution pH<7can help improve theabsorption of reactive brilliant red while pH>7can lead to great increase of methyleneblue absorption. The absorption of reactive brilliant red can reach to118.3mg/g whenpH=2. The absorption of methylene blue can reach high to132.5mg/g when pH=13.Pseudo second-order adsorption model provides the most fittings for the adsorption ofboth dyes on the absorbent with all R2greater than0.99. Absorption isotherm indicatedthe absorptions of the two dyes are monolayer absorptions. The activation energy valuesof reactive brilliant red and methylene blue are5.01kJ/mol and6.93kJ/mol separately.