Minimization The Chemical Oxygen Demand (COD) Content in Tannery Wastewater Using Activated Carbon from Spent Tea Leaves

Water pollution from tannery wastewater is a serious environmental issue. This study aimed to investigate the potential of spent tea leaves as activated carbon (AC) to minimize chemical oxygen demand (COD) of tannery effluent. To determine the best conditions for minimizing COD, a batch adsorption process was conducted, involving various factors such as different adsorbent dosages (ranging from 1 to 11 gm L-1), contact time (30 to150 min), and pH values (ranging from 3 to 11). The characterization was done by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM). The outcomes of this study demonstrated that using 1.5 M H2SO4 as activating agents resulted in iodine values of 750.52 mg g-1. Employing a higher concentration of H2SO4 had several positive effects, such as minimizing total dissolved solids (TDS) and turbidity, increasing dissolved oxygen (DO), and lowering COD in tannery wastewater. The most significant COD reduction, reaching 96.16%, was achieved with a dosage of 5 gm L-1. Furthermore, the data collected from these experiments were analyzed using the Langmuir isotherm model, which provided an excellent fit (R2 = 0.9837 and qmax = 5.186 mg g-1). Based on these result, it can be concluded that 1.5 M H2SO4 is the optimal choice for developing activated carbon from spent tea leaves. Additionally, the resulting activated carbon proves to be an effective adsorbent for minimizing COD from tannery wastewater.