Efficient removal of methylene yellow dye by activated carbon-chitosan composite beads

Abstract

Pakistan is facing severe water scarcity and grappling with significant water pollution concerns, this study endeavors to address these environmental challenges. The focus of this research is the synthesis and application of activated carbon-based composite beads for pollutant removal and water purification. To achieve this goal, biopolymer composite beads were created using chitosan (Cs) as the matrix and activated carbon as the filler, yielding two types of beads: Cs blank beads and Cs/AC beads. These beads underwent examination of surface morphology via scanning electron microscopy (SEM) and the structural composition elucidated through FTIR spectroscopy. The presence of chitosan polymer was verified at characteristic wavenumbers such as 3298 cm-1 (N-H stretching), 2905 cm-1 (C-H stretching), 1570 cm-1 (NH bending), 1377 cm-1 (C-O-C), and 1033 cm-1 (C-OH). Furthermore, the study explored the adsorption capabilities of Cs/AC beads in the context of removing methylene yellow dye, a prevalent waterborne pollutant. The adsorption efficiency was examined with careful consideration of variables such as exposure time, adsorbent dose and pH. A systematic optimization process was employed to maximize the removal efficiency. Notably, the adsorption/removal of methylene yellow dye commenced upon exposure to Cs/AC, and after 150 minutes, a steady state was reached (92% removal), indicating no further removal. Consequently, this time point was identified as the optimal contact duration for subsequent investigations. Besides, a slightly acidic pH of 7 within the solution, coupled with higher concentrations of the adsorbent, was identified as the optimal condition. This research provides valuable insights into mitigating water pollution and improving water quality in Pakistan through the development and utilization of advanced composite materials.