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Removal of Arsenic(III) and Chromium (VI) from Contaminated Water using a Low-Cost Chitosan Coated Polymers
Citation:
DeMessie, J., G. Sorial, AND B. Mezgebe. Removal of Arsenic(III) and Chromium (VI) from Contaminated Water using a Low-Cost Chitosan Coated Polymers. American Chemical Society National Meeting & Exposure, Chicago, IL, August 21 - 24, 2022.
Impact/Purpose:
This study determined the use of novel biopolymer adsorbent to remove Arsenic (III) and Chromium (VI) from contaminated water. An adsorbent was developed by coating chitosan, a naturally and abundantly available biopolymer from different waste plastics. The laboratory result proved that biopolymer adsorbents could significantly and efficiently remove Arsenic (III) and Chromium (VI) from the sample.
Description:
Access to clean water has been a global challenge since long-term exposure to heavy metal pollutants such as arsenic(As(III) and chromium (Cr(VI)) has detrimental health effects. Thus, developing a low-cost technology to provide clean drinking water is vital. A novel adsorbent was developed by coating chitosan, a naturally and abundantly available biopolymer, with three selected types of waste plastics. Three waste plastic materials, polypropylene (PP), polyamide (PA), and polystyrene (PS), were screened for adsorbent support, and Polyamide (Nylon-12 nano-bead) was selected. The biosorbent was characterized by Fourier-transform infrared spectroscopy (FTIR) spectra, thermogravimetric analysis, surface charge analysis, and imaging techniques. The removal of Cr(VI) and As(III) was determined using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Equilibrium and column flow adsorption of As(III) and Cr(VI) on the biosorbent were studied. The effect of pH, concentration of adsorbate and amount of adsorbent on the removal efficiency were investigated. Equilibrium data were fitted to Langmuir and Freundlich adsorption isotherms, and the maximum monolayer adsorption capacities were 98.9mg/L and 21.5mg/g for Cr(VI) and As(II), respectively. Kinetics studies and column performance were studies on the effects of chitosan–PA for inlet Cr(VI) and As(III) solutions. The adsorbent’s breakthrough curve was analyzed using the bed-depth service time Thomas model to define breakthrough behavior. Novel regeneration and reuse of exhausted adsorbents were achieved via a chelating ligand complex EDTA (ethylenediaminetetraacetate) solution, effectively lengthening the lifespan of the adsorbent. This adsorbent system could improve the quality and accessibility of water in developing countries.