Removal of NO 3 -N in alkaline rare earth industry effluent using modified coconut shell biochar

• Published in: Water science and technology Vol. 80; no. 4; p. 784
• Main Authors: You, Hanyang, Zhang, Yi, Li, Wenying, Li, Yang, Ma, Yanfei, Feng, Xuedong
• Format: Journal Article
• Language: English
• Published: England 01.08.2019
• Subjects: Adsorption; Charcoal; Cocos; Water Pollutants, Chemical
• ISSN: 0273-1223

Coconut shell biochar (CSB) was selected as raw material to obtain two kinds of modified biochars by pickling and iron modification. The pickling coconut shell biochar (PCSB) and pickling-iron modified coconut shell biochar (PICSB) were used as adsorbents to remove NO -N in alkaline rare earth industry effluent. The results showed that pickling smoothed the surface of CSB, and α-FeOOH was formed on the surface of PCSB because of FeCl solution modification. Suitable adsorbent dosages of PCSB and PICSB were both 2.0 g/L. The NO -N adsorption process by PCSB and PICSB both reached equilibrium at 30 min. The quasi-first-order kinetic model shows good fit to the NO -N adsorption by PCSB. Whereas, the quasi-second-order kinetic model is more suitable for PICSB adsorbing NO -N. The adsorption mechanisms of PICSB for NO -N removal were ligand exchange and electrostatic attraction, and that of PCSB for NO -N removal was electrostatic attraction. The NO -N adsorption amounts of PCSB and PICSB decreased with increasing adsorption temperature and pH. The maximum NO -N adsorption amounts of PCSB and PICSB were 15.14 mg/L and 10.75 mg/L respectively with adsorbent dosage of 2.0 g/L, adsorption time of 30 min, adsorption temperature of 25 ± 1 °C, and initial solution pH of 2.01.