Adsorptive Characteristics of Pb (Ⅱ) by Sludge and Rice Hull Co-combustion Ash

LYU Yi; WU Shuya; ZHOU Xian; CHEN Yuchi; WANG Teng; ZHOU Min; HOU Haobo

doi:10.19672/j.cnki.1003-6504.2018.05.007

Abstract：Husk and municipal sludge co-combustion is a promising municipal sludge disposal method for energy, the cocombustion ash produced from the process is a neglected resource. This article researched the pretreated co-combustion ash applied in the lead polluted wastewater disposal, physical and chemical characteristics of the co-combustion ash was studied with different sludge mixing ratio. The adsorption characteristics was discussed in different p H and initial Pb2+concentration, following by the kinetics research, and finanally the adsorption mechanism was explored. The result showed that the Pb2+adsorption capacity of co-combustion ash is equal to those ashes modified by complicated process. The raw material mixing ratio to the highest adsorption efficiency was 60％ for sludge and 40％ for rice husk, when the fuel temperature is 900 ℃. The adsorption efficiency is over 90％, when the p H value is 5 and the initial Pb2+concentration is below 400 mg/L. Langmuir was better than Freundlich model to fit the adsorption process. The maximal adsorption capacity fitted by Langmuir isothermal adsorption model was 108.7 mg/g. Kinetics show the adsorption process mainly happened in the first 5 h. In the adsorption process, the silanol hydrolyzed by amorphous silicon dioxide plays the most important role. The adsorption products can be Pb2SiO4 or PbSiO3·x H2O, which is decided by isolated hydroxy and coupled hydroxy in the surface of amorphous SiO2.