REMOVAL OF CHROMIUM (VI) FROM HYDROMETALLURGICAL EFFLUENTS USING MORINGA WASTE: ISOTHERM, KINETICS AND THERMODYNAMIC STUDIES

Heavy metal ions are harmful to aquatic life, people, and the environment, and they have been a significant source of concern for researchers for a long time. They are a public health concern since they do not biodegrade as organic contaminants do in industrial effluents. This study uses moringa waste as a bio-sorbent to remove Cr (VI) from hydrometallurgical effluents. Cr (VI) is more harmful because of its high mobility in the environment and capacity to cause cancer in organisms. Moringa waste was pyrolyzed and modified with phosphoric acid to develop a bio-sorbent. FTIR and SEM were used to determine the surface functional groups and examine the bio-sorbent's morphology and microstructure. FTIR examination revealed the moringa waste structure’s stability and aromaticity, confirmed by peaks around 1600 cm⁻¹. Because aromatic rings contribute to a large surface area and porosity and are stable, they are important for adsorption applications. At 75 minutes of contact time with 6 pH and a 1.5g adsorbent dosage at 55 ^oC, the removal percentage was found to be 68%. Adsorption data indicated a good fit to the Langmuir isotherm model, indicating that chromium VI was covered in a monolayer on the surface of the moringa waste. It could be that the adsorption rate is affected by the amount available of sites on the bio-sorbent, as the pseudo-second-order model indicated the kinetics that followed. The thermodynamic study showed that the process is endothermic and spontaneous, hence making the application of moringa waste in wastewater treatment viable.