Trivalent chromium adsorption efficiency on thermic waste mosquito coil adsorbent from tannery wastewater

• Thermic waste mosquito coil adsorbent (TWMCA) used for Cr-adsorption. • FTIR, SEM, and EDX analysis were performed to characterize TWMCA. • Optimized conditions Cr-adsorption on TWMCA achieved 99.97 % from tannery wastewater. • PSO kinetics model and Freundlich isotherm well fitted for Cr-adsorption on TWMCA. • Reduction of BOD5, Cl-, TDS, and COD achieved at 81.17 %, 68.85 %, 53.8 %, and 50 %. Emitted tannery wastewater containing trivalent chromium, Cr(III) is a significant environmental issue. Thus, performance evaluation of highly available and low-cost adsorbents has been investigated. There is much scope remaining to utilize alternative waste (adsorbent) for their availability and removal efficiency. This study is focused on the Cr(III) adsorption on the thermic waste mosquito coil adsorbent (TWMCA) from tannery wastewater. The TWMCA was characterized by Scanning Electronic Microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, Energy dispersive X-ray (EDX), and pH point of zero charge (pHpzc). The Cr adsorption was achieved at 99.97 % with optimum condition (dose 1.0 g/50 mL wastewater, stirring time 30 min, settling time 6 h, and at 40 °C temperature with a relative solution pH 6.3) which showed a reduction of biochemical oxygen demand, chloride, chemical oxygen demand, total dissolved solids, and electrical conductivity by 81.17 %, 68.85 %, 50.00 %, 53.77 %, and 45.43 %, respectively. The Freundlich isotherm (R 2 =0.9893) and pseudo-second-order kinetic model (R 2 =0.9999) well-explained the Cr adsorption on TWMCA. The well-fitted adsorption mechanism was described with the help of pHpzc. The desorption study suggests the reusability of TWMCA. Hence, using TWMCA for Cr adsorption from tannery wastewater is an effective technique to save the environment. A sustainable and efficient adsorption technique utilizing another waste drives industries toward environmentally conscious waste management practices that satisfy the Sustainable Development Goal.