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Removal of endocrine disrupting chemicals from contaminated industrial groundwater using chitin as a biosorbent
Author(s) -
Krupadam Reddithota J.,
Sridevi P.,
Sakunthala Sistu
Publication year - 2011
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.2525
Subject(s) - chitin , adsorption , chemistry , freundlich equation , langmuir , nuclear chemistry , aqueous solution , fourier transform infrared spectroscopy , langmuir adsorption model , biosorption , chromatography , environmental chemistry , chemical engineering , chitosan , organic chemistry , sorption , engineering
Abstract BACKGROUND: The removal of endocrine disrupting chemicals (EDCs) from drinking water is of great importance. Chitin isolated from crab shells was used as a biosorbent for removal of three EDCs—benzo(a)antracene, β‐estradiol and bisphenol A—present in contaminated groundwater. Fourier transform infra‐red (FTIR) spectroscopy, porosimetry and scanning electron microscope (SEM) were used for structural elucidation of chitin. Experiments were conducted using batch adsorption mode under different conditions of initial EDCs concentration, solution pH and adsorbent dose. The effect of chitin particle size was also investigated. Batch adsorption data were fitted to Langmuir and Freundlich isotherms and pseudo‐first‐ and second‐order models for kinetic study. RESULTS: The maximum adsorption capacity of chitin by the three EDCs, calculated using the Langmuir equation, ranged from 42.9 to 84 mg g −1 . The adsorption of EDCs by chitin was due primarily to electrostatic forces. The measurement of zeta potential indicated that chitin has higher surface charge in alkaline pH, resulting in reduction in removal of EDCs with increasing pH. Complementary to the experimental results molecular simulations were also performed on HyperChem software to understand the adsorption mechanism between chitin and EDCs in aquesous solutions. Chitin was regenerated after washing with methanol/acetic acid (1/3, v/v) and the regeneration process was repeated for 10 cycles, which showed 90% adsorption capacity retained by chitin. CONCLUSIONS: The experimental results suggest that chitin could be employed as an adsorbent in the removal of EDCs from aqueous solutions, and the adsorption potential of used chitin can be recovered by methanol/acetic acid solvent washings. The reusable biosorbent chitin would be cost‐effective and a better option for future water remediation endeavours. Copyright © 2010 Society of Chemical Industry