Enhanced removal of pentachlorophenol by a novel composite: Nanoscale zero valent iron immobilized on organobentonite

• Published in: Environmental pollution (1987) Vol. 159; no. 12; pp. 3744 - 3749
• Main Authors: Li, Yimin, Zhang, Yun, Li, Jianfa, Zheng, Xuming
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.12.2011; Elsevier
• Subjects: Adsorption; Applied sciences; bentonite; Bentonite - chemistry; Biological and physicochemical phenomena; chemistry; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Restoration and Remediation; Environmental Restoration and Remediation - instrumentation; Environmental Restoration and Remediation - methods; Exact sciences and technology; Immobilization; instrumentation; ions; Iron; Iron - chemistry; Kinetics; Mass transfer; methods; Nanocomposites; Nanocomposites - chemistry; Nanomaterials; Nanoscale zero valent iron; Nanostructure; Natural water pollution; Organobentonite; Particle Size; Pentachlorophenol; Pentachlorophenol - chemistry; phenol; Pollution; Pollution, environment geology; Removal; Surface chemistry; Water Pollutants, Chemical; Water Pollutants, Chemical - chemistry; Water treatment and pollution; X-Ray Diffraction; Removal; Immobilization; Organobentonite; Pentachlorophenol; Nanoscale zero valent iron; Organic clay; Adsorption capacity; Zerovalent metal; Iron; Organic chlorine compounds; Composite material; Carcinogen; Decontamination; Phenols; Poison; Water pollution; Organic compounds
• ISSN: 0269-7491; 1873-6424; 1873-6424
• DOI: 10.1016/j.envpol.2011.07.016

Nanoscale zero valent iron (NZVI) was immobilized on the organobentonite (CTMA-bent), so as to enhance the reactivity of NZVI and prevent its aggregation. This novel composite (NZVI/CTMA-Bent) was characterized by transmission electron microscope and X-ray diffraction. Good dispersion of NZVI particles on the bentonite was observed. Its performance on removing pentachlorophenol (PCP) was investigated by batch experiments. Results showed NZVI/CTMA-Bent could rapidly and completely dechlorinate PCP to phenol with an efficiency of 96.2%. It was higher than the sum (54.5%) of reduction by NZVI (31.5%) and adsorption by CTMA-Bent (23.0%) separately. The kinetic studies indicated the removal rate of PCP was positively related to the adsorption. We proposed that the adsorption of PCP by CTMA-Bent enhanced the mass transfer of PCP from aqueous to iron surface. Besides, NZVI/CTMA-Bent exhibited good stability and reusability, and CTMA-Bent could also reduce the amount of iron ions released into the solution. ► CTMA-Bent as the carrier can prevent NZVI from aggregation. ► CTMA-Bent promoted the mass transfer of PCP from solution to NZVI surface, leading to the enhanced removal efficiency. ► The NZVI/CTMA-Bent composite exhibited good stability and reusability. NZVI immobilized on CTMA-Bent showed enhanced efficiency on removing pentachlorophenol, indicating synergetic effect between NZVI and CTMA-Bent.