International Journal of Environmental Science and Development

Abstract—Microplastics are a serious concern today because of their huge quantities in the environment, their ability to adsorb toxins on surfaces, their ease of entry in the food chain based on micron size, and theirs contributing to increased potential health threats. However, a new aspect of microplastics’ presence impacting the pollutant treatment efficiency is poorly understood. This study clarifies the effects of microplastics on the adsorption process of Cr(VI) by biochar, an effective and inexpensive material for wastewater treatment. Techniques such as Fourier Transform Infrared (FTIR) Spectroscopy, Nitrogen adsorption/ desorption, and Scanning Electron Microscope (SEM) were used to assess the characteristics of adsorbents. The results showed that biochar had a large surface area and pore volume (313.91 m2/g; 0.45 cm3/g); these values were significantly higher than polypropylene microplastics (7.04 m2/g; 0.007 cm3/g). Biochar’s pores were mainly micropores (less than 2 nm), while polypropylene’s ones were mesopores (2 to 50 nm). Batch experiments were conducted following the influencing factors. Adsorption data indicated that Freundlich, Sips, and Redlich-Peterson isotherms were suitable for Cr(VI) adsorption by biochar. The Freundlich and Redlich-Peterson isotherms described well the adsorption of Cr(VI) well by the mixture of biochar and polypropylene microplastics. For kinetic data, second-order kinetics was more suitable than first-order kinetics for Cr(VI) adsorption onto the materials. The Elovich diffusion and liquid film diffusion models are suitable for describing the adsorption pathway of Cr(VI) on a mixture of microplastics and biochar. In conclusion, microplastics significantly affect the adsorption of Cr(VI) by biochar.

Keywords—adsorption, biochar, Cr(VI), microplastics, polypropylene

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Cite: Ho Truong Nam Hai, Pham Thi Phuong Le, Nguyen Thao Nguyen, Nguyen Thi Thanh Nhon, Nguyen Tran Hanh Vy, Tan Le Hoang Doan, To Thi Hien, "Potential Impacts of polypropylene Microplastics on the Adsorption Process of Cr(VI) by Biochar," International Journal of Environmental Science and Development vol. 15, no. 5, pp. 268-276, 2024.

Copyright © 2024 by the authors. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).