Dye adsorption on fish scale biosorbent from tannery wastewater

In leather processing, dyeing is an essential operation to make it attractive for fashion style. Emitted dyeing wastewater contains dye, fixing agent, syntan, resin, and fat. Dye removal from real wastewater is challenging because it includes other matrices. Dyes in wastewater have an adverse influence on the aquatic ecosystem. This research concerns the suitability of fish biowaste adsorbent for dye removal from tannery wastewater. The obtained biosorbent was analyzed through Fourier Transform Infrared (FTIR) Spectroscopy, pH point of zero charge (pHpzc), Energy Dispersive Spectroscopy (EDS), and Scanning Electron Microscope (SEM). The dye removal efficiency was evaluated by monitoring the biosorbent dose, settling time, stirring time, and temperature effect. The dye adsorption mechanism was characterized using Freundlich and Langmuir’s regression models. The maximum dye removal efficiency (81.8 %) was achieved with a 2 g biosorbent dose per 50 mL of wastewater, 25 min stirring time, 30°C temperature, and 20 h settling time at pH 4.8. The adsorption kinetics demonstrated that the pseudo-second-order reaction (PSO) model shows a good regression coefficient (R²=0.94). The removal of Total Dissolved Solids (TDS), Biochemical Oxygen Demand (BOD), turbidity, and Chemical Oxygen Demand (COD) were 39.8 %, 69.7 %, 48.1 %, and 90.1 %, respectively. Hence, the fish scale biosorbent could be a feasible adsorbent for leather dyeing wastewater treatment, and further research can be conducted to explore its potential for large-scale application.