Removal of Chromium (VI) from Hydrometallurgical Effluents Using Moringa Waste: Isotherm, Kinetic and Thermodynamic Studies

The study aims to promote environmental restoration by shedding light on the potential use of moringa waste as an inexpensive, eco-friendly adsorbent for treating wastewater contaminated with Chromium (VI). FTIR was used to characterise the surface functional groups of moringa waste. The one-factor-at-a-time method was used to study the initial concentration in milligrams per litre, contact time in minutes, temperature in degrees Celsius, pH, and adsorbent dosage in milligrams per litre. The output was the removal percentage. Furthermore, adsorption isotherms, kinetics, and thermodynamic models were applied to understand the process behaviour. FTIR examination revealed the moringa waste structure’s stability and aromaticity, confirmed by peaks located around 1596 cm−1 and the stretching of the hydroxyl group around 3321 cm−1, which are important for enhancing Cr (VI) adsorption due to their capability to establish strong bonds with metal ions. Aromatic rings contribute to a large surface area and porosity and are stable; this is important for adsorption applications. At 60 min of contact time with a pH of 6 and 0.5 g of adsorbent dosage at 45 °C for a concentration of 100 mg/L, the highest removal percentage was found to be 77.03%. Adsorption data values indicated a good fit to the Langmuir isotherm model. The thermodynamic study showed that the process is endothermic and spontaneous, hence making the application of moringa waste in wastewater treatment viable.