Adsorption of Cu2+and Zn2+by extracellular polymeric substances (EPS) in different sludges: Effect of EPS fractional polarity on binding mechanism.
Extracellular polymeric substances (EPS) in sludge samples played a major role in heavy metals removal during wastewater treatment. In this study, the binding quality, adsorption mechanism, as well as the chemical fractional contribution of the sludge EPS from activated sludge, anaerobic granular sludge and anaerobic flocculent sludge to the adsorption of Zn2+and Cu2+was investigated. For all three sludge samples, Cu2+could be more easily adsorbed than Zn2+, and EPS extracted from the anaerobic granular sludge exhibited a relatively higher adsorption capacity than that of anaerobic flocculent sludge and activated sludge. Specifically, hydrophobic EPS of the activated sludge and anaerobic flocculent sludge was more efficient in adsorbing Cu2+and Zn2+than that of the hydrophilic EPS. However, hydrophilic EPS in anaerobic granular sludge played a greater role in heavy metals removal. The adsorption of those two heavy metals onto the unfractionated and hydrophobic EPS could be better described by the Langmuir isotherm, while Freundlich models fitted hydrophilic EPS. In addition, the effect of the heavy metals adsorption on the spectrum characteristics of the sludge EPS was also explored by analysis of FT-IR and fluorescent spectra.
State Key Laboratory of Urban Water Resources and Environment (SKLUWRE); School of Municipal & Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
Liangliang
L
Wei
State Key Laboratory of Urban Water Resources and Environment (SKLUWRE); School of Municipal & Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
Yang
Y
Li
Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
Daniel R
DR
Noguera
State Key Laboratory of Urban Water Resources and Environment (SKLUWRE); School of Municipal & Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
Ningbo
N
Zhao
State Key Laboratory of Urban Water Resources and Environment (SKLUWRE); School of Municipal & Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
Yue
Y
Song
State Key Laboratory of Urban Water Resources and Environment (SKLUWRE); School of Municipal & Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
Jing
J
Ding
State Key Laboratory of Urban Water Resources and Environment (SKLUWRE); School of Municipal & Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China. Electronic address: zhql1962@163.com.
Qingliang
Q
Zhao
State Key Laboratory of Urban Water Resources and Environment (SKLUWRE); School of Municipal & Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
Fuyi
F
Cui
D000327:Adsorption; D000465:Algorithms; D064753:Ammonium Hydroxide / Q000737:chemistry; D000693:Anaerobiosis; D003300:Copper / Q000737:chemistry* / Q000302:isolation & purification; D007700:Kinetics; D011108:Polymers / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry*; D013816:Thermodynamics; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical; D015032:Zinc / Q000737:chemistry* / Q000302:isolation & purification
D011108:Polymers; D012722:Sewage; D014874:Water Pollutants, Chemical; D064753:Ammonium Hydroxide; D003300:Copper; D015032:Zinc
Adsorption; Fractionation; Heavy metals; Kinetics; Sludge EPS