Biochar characteristics produced from rice husks and their sorption properties for the acetanilide herbicide metolachlor

• Published in: Environmental science and pollution research international 2017-02, Vol.24 (5), p.4552-4561
• Main Authors: Wei, Lan, Huang, Yufen, Li, Yanliang, Huang, Lianxi, Mar, Nyo Nyo, Huang, Qing, Liu, Zhongzhen
• Format: Article
• Language: English
• Subjects: Acetamides - chemistry; Acetanilide; Adsorption; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Charcoal; Charcoal - chemistry; Chemical bonds; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Fourier transforms; Herbicides; Herbicides - chemistry; Hot Temperature; Hydrogen bonding; Hydrogen bonds; Infrared analysis; Infrared spectroscopy; Metolachlor; Oryza - chemistry; Pyrolysis; Research Article; Scanning electron microscopy; Sorption; Surface area; Surface chemistry; Temperature; Temperature effects; Titration; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-016-8192-x

Rice husk biochar (RHBC) was prepared for use as adsorbents for the herbicide metolachlor. The characteristics and sorption properties of metolachlor adsorbed by the RHBC prepared at different pyrolysis temperatures were determined by analysis of physico-chemical characteristics, Fourier transform infrared spectroscopy (FTIR), Boehm titration, scanning electron microscopy (SEM), and thermodynamics and kinetics adsorption. With increasing pyrolysis temperature, the RHBC surface area greatly increased (from 2.57 to 53.08 m 2  g −1 ). RHBC produced at the highest temperature (750 °C) had the greatest surface area; SEM also showed the formation of a porous surface on RH-750 biochar. The sorption capacity of RHBC also increased significantly with increasing pyrolysis temperature and was characterized by the Freundlich constant K f for the adsorption capacity increasing from 125.17–269.46 (pyrolysis at 300 °C) to 339.94–765.24 (pyrolysis at 750 °C). The results indicated that the surface area and pore diameter of RHBC produced with high pyrolysis temperature (i.e., 750 °C) had the greatest impact on the adsorption of metolachlor. The FTIR, Boehm titration, and SEM analysis showed that the greatest number of surface groups were on RHBC produced at the lowest temperature (300 °C). The biochars produced at different pyrolysis temperatures had different mechanisms of adsorbing metolachlor, which exhibited a transition from hydrogen bonds dominant at low pyrolytic temperature to pore-filling dominant at higher pyrolytic temperature.