Adsorption of copper and lead ions onto regenerated sludge from a water treatment plant.
In this study, water treatment sludges were sintered under various experimental conditions to generate Al-containing adsorbents. The adsorption of Cu2+ and Pb2+ onto sintered oxide was examined and sorption results were further modeled using a surface complex model. The specific surface area of the sintered adsorbent was substantially reduced from 30 m2/g (dried sludge) to 2 m2/g (sinter sludge). The pH-adsorption-edges of both Cu2+ and Pb2+ were shifted towards a higher pH than the edges of the unsintered adsorbent, revealing reduced affinity of the sintered adsorbent for metal ions. Metal leaching was measured by the TCLP procedure, and the results indicated that the amount of metal leaching by the sintered adsorbent was negligible. The effect of background electrolytes on Cu2+ and Pb2+ sorption was negligible. Triple-layer model (TLM) simulation revealed that Cu2+ and Pb2+ sorption on sintered adsorbent involves inner-sphere interactions and the dominant surface metal species are monodentates of Me2+ and MeOH+. The intrinsic adsorption constants of Cu2+ and Pb2+ on dried sludge, adsorbent sintered at 1000 degrees C, and adsorbent sintered at 1100 degrees C were also examined.
Wu
Chung-Hsin
CH
Department of Environmental Engineering and Health, Yuanpei University of Science and Technology, Hsinchu, Taiwan, ROC. chwu@mail.yust.edu.tw
Lin
Cheng-Fang
CF
Horng
Pay-Yu
PY
D000327:Adsorption; D003300:Copper / Q000302:isolation & purification*; D004573:Electrolytes; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000302:isolation & purification*; D008962:Models, Theoretical; D010087:Oxides / Q000737:chemistry; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
D004573:Electrolytes; D010087:Oxides; D012722:Sewage; D007854:Lead; D003300:Copper