Phosphate removal by lead-exhausted bioadsorbents simultaneously achieving lead stabilization.
Low-cost adsorbents have been continuously developed for heavy metal removal, but little information is available concerning the follow-up treatment of the toxic metal-laden adsorbents. In this study, an optional strategy was provided for the further treatment of heavy metal-impregnated low-cost adsorbents through employing them for phosphate retention. The enhancement of phosphate adsorption by the sorbed lead was first validated using several types of raw or modified waste biomass. Tea waste-supported hydrated manganese dioxide (HMO-TW) with the highest Pb sorption capability was then chosen to systematically evaluate phosphate retention. Phosphate adsorption onto lead-laden HMO-TW (HMO-TW(Pb)) was pH-insensitive with only slight decline at pH > 8.5, and was barely affected by competing anions owing to the specific surface precipitation mechanism. Moreover, no signs of lead leakage from HMO-TW(Pb) were observed during phosphate adsorption at a wide pH range (4.2-11.3) and high ion strength (0-250 mg L-1NaNO3). The lead on HMO-TW(Pb) was greatly stabilized through phosphate retention, which also reduced the environmental risks of their following treatment such as solidification and landfill. Additionally, the phosphate adsorption onto HMO-TW(Pb) was quick (with equilibrium time <60 min) and barely affected by temperature. Fixed-bed column test further suggested that HMO-TW(Pb) has practical applicability in efficient removal of phosphate from water.
College of Environment, Zhejiang University of Technology, Hangzhou 310014, China; College of Life & Environmental Sciences, Huangshan University, Huangshan 245041, China.
Shunli
S
Wan
College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
Jiayu
J
Wu
College of Environment, Zhejiang University of Technology, Hangzhou 310014, China. Electronic address: fenghe@zjut.edu.cn.
Feng
F
He
College of Life & Environmental Sciences, Huangshan University, Huangshan 245041, China.
Shanshan
S
Zhou
College of Life & Environmental Sciences, Huangshan University, Huangshan 245041, China.
Rui
R
Wang
Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL 32611, United States.
Bin
B
Gao
College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
Jianmeng
J
Chen
D000327:Adsorption; D000838:Anions; D001665:Binding Sites; D000075322:Heavy Metal Poisoning; D007700:Kinetics; D007854:Lead / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D009994:Osmolar Concentration; D010087:Oxides / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D011041:Poisoning; D013696:Temperature; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
D000838:Anions; D017895:Manganese Compounds; D010087:Oxides; D010710:Phosphates; D014874:Water Pollutants, Chemical; D014867:Water; D007854:Lead; C016552:manganese dioxide
Adsorption; Bioadsorbent; Lead stabilization; Phosphate removal