An innovative eco-friendly approach: treatment of cottage dyeing effluent using natural coagulant.

Coagulation is one of the cost-effective and efficient methods to treat the textile industry dyeing effluent. Natural coagulants have plenty of advantages over the treatment of dyeing effluents. A laboratory scale experiment was performed to address the treatment of textile dyeing effluent using Madhuca longifolia (Iluppai) oil cake powder (MCP) as a coagulant, sourced from natural indigenous plant-based materials. The coagulant dosage, pH and dye concentration are varied, evaluated and optimized in the lab scale batch coagulation process, and its characterization was performed by "Fourier transform infrared spectroscopy (FTIR), UV-visible spectrophotometer, X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) analysis and also zeta potential". Various dosages of MCP were introduced, and the coagulation process was evaluated by examining and comparing the initial and final characteristics of Acid Blue 114 (AB114) dyeing effluent, including pH, chemical oxygen demand (COD), turbidity and colour. In terms of MCP dosage, the maximum efficiency for removing turbidity, COD and colour is 96%, 74.8% and 94.8%, respectively, at the coagulant dose of 2.7 g. The removal efficiency of turbidity, COD and colour is increased when the pH level is 4. The coagulant dose of 2.7 g of MCP has given the maximum turbidity, COD and colour removal efficiency of 97.6%, 75.6% and 95.8%, respectively, at an acidic state of pH 4. The study also investigates the equilibrium adsorption capacity (q_e) of the MCP coagulant material. The obtained values are analyzed and fitted to isotherms, including Langmuir and Freundlich, as well as kinetic models like pseudo-first order and pseudo-second order. The indigenous plant-based material (MCP) is a locally available, cost-effective novel by-product material. It proves to be a viable alternative for treating industrial effluent, demonstrating superior efficiency compared to chemical-based coagulants.