Abstract:
Untreated industrial wastewater discharged into the environment has a detrimental impact on human health and the ecosystem. Textile manufacturing is one industry that produces a substantial amount of wastewater. The effluent from this sector contains a variety of toxins that must be treated before being released into the environment. Methylene blue, a major compound commonly used in textile manufacturing, is present in high concentrations in textile factory effluent and poses a significant hazard as it is highly toxic and carcinogenic. Wastewater treatment is also costly for the industry. This study aims to remove methylene blue from synthetic wastewater using activated carbon derived from the low-cost plant Cycas thouarsii (Sago) seeds through batch mode investigations. The adsorbent was activated using chemical and thermal procedures and characterized using FTIR and XRF analysis. The adsorption isotherm and kinetics were also examined. The experimental design encompassed five factors with six levels each: pH (2, 4, 6, 8, 10, and 12), initial MB concentration (40, 65, 90, 115, 140, and 165 mg/L), adsorbent dosage (0.01, 0.05, 0.1, 0.15, 0.20, and 0.25 mg/100 mL), contact time (30, 40, 50, 60, 70, and 80 min), and agitation speed (25, 50, 75, and 120 rpm). For optimization purposes, synthetic wastewater was created in the laboratory, and the optimal parameters for complete dye removal were determined to be starting concentration: 115 ppm, contact time: 50 min, adsorbent dose: 0.2 g/L, pH: 8, and agitation speed: 75 rpm. Among the three adsorption isotherm models, the Langmuir isotherm model exhibited the best fit with an experimental value of R2 = 0.99, indicating a homogeneous and monolayer adsorption process. The kinetics study also demonstrated a good fit with the pseudo-second-order model at R2 = 0.99, suggesting that the adsorption mechanism involves chemisorption, with the rate-limiting step potentially being the sharing or exchange of electrons between the adsorbate and adsorbent. Overall, this adsorption technique shows great promise for industrial-scale application.
