Turning teawaste particles into magnetic bio-sorbents particles for arsenic removal from wastewater: Isotherm and kinetic studies

The primary objective of this research was to assess the potential of magnetic bleached biochar (MBBC) as a cost-effective adsorbent for arsenic removal. To achieve this, locally collected tea wastes underwent meticulous cleaning, bleaching, and modifications via thermal and chemical treatments. Both non-magnetic and magnetic biochar adsorbents were thoroughly characterized using Fourier transform-infrared spectroscopy (FT-IR) and thermo-gravimetric analysis (TGA). Subsequently, the adsorptive performance of MBBC in removing arsenic from wastewater samples was investigated, considering various crucial parameters such as adsorbent-adsorbate contact time, concentration of As, temperature, adsorbent dosage, and the regeneration-ability of the adsorbent. The experimental data for the adsorption process were best represented by the Langmuir isotherm, indicating its suitability for the MBBC adsorbent. Remarkably, the MBBC demonstrated a maximum Langmuir adsorption capacity of approximately 714 mg/g at room temperature, highlighting its efficiency as an arsenic adsorbent. Furthermore, the Lagergren's Pseudo-second order kinetic model proved to be the most suitable for describing the adsorption kinetics, confirming the chemisorption nature of the process. The results also indicated that the adsorption process is endothermic and feasible, suggesting its viability for practical applications. Taking all findings into account, the comprehensive analysis strongly supports the potential use of MBBC as a highly promising and cost-effective adsorbent for efficiently removing arsenic from aqueous samples. This research contributes valuable insights to the field of wastewater treatment and offers a sustainable and environmentally friendly solution for tackling arsenic contamination in water sources.