Removal of phenol and 4-chlorophenol from synthetic wastewater by using mango husks adsorbents

Abstract

This study investigated the efficiency of powdered, carbonized, and activated mango husks in removing environmental organic pollutants, especially phenol, and 4-chlorophenol from synthetic wastewater. Both powdered mango husks were characterized by using the FTIR spectrophotometer. The removal efficiency of these adsorbents through UV-Vis spectroscopy by finding out the concentration of adsorbate ( phenol and 4-chlorophenol) in the treated solutions. Results from this analysis indicated the presence of -OH (3450-3300 cm-1), non-aromatic C-H (2900 cm-1), C=O (1737.58 cm-1), and C-O (1236.86 cm- 1) on the original powder, while activated mango husks indicated absorption (1500-1400 cm-1) and (1200-1100 cm-1) indicating the existence of P=O and P-O functions, respectively. These results confirmed that mango husk components degraded by undergoing chemical changes as a result of acidic activation. Additionally, the effects on parameters including dosage, contact time, temperature, initial concentration of adsorbate on phenol and 4-chlorophenol were examined and were discovered to be 0.4 g for powdered mango husks, carbonized mango husks, and 0.3 g for activated mango husks, 180 min, pH 8 for powdered mango husks, pH 7 for carbonized mango husks and activated mango husks and, 30˚C,80 ppm respectively. While for 4-chlorophenol the results were 0.4 g, 180 min, pH 7 for Carbonized mango husks, powdered mango husks and pH 5 for activated mango husks, pH 7 for carbonized, mango husks, and powdered mango husks, 30˚C and 80 ppm respectively. Furthermore, phenol adsorption fitted excellently to the Langmuir adsorption isotherm onto activated mango husks which indicated a monolayer and homogeneous adsorption mechanism while 4-chlorophenol fitted with the Freundlich adsorption isotherm onto Carbonized mango husks with a predominance of physical adsorption on heterogeneous site. In addition, activated mango husks on phenol and activated mango husks on 4-chlorophenol fitted with Pseudo-second order respectively. Additionally, batch and column flow adsorption modes were tested, and their results indicated that columns have a high removal efficiency of 92.1% compared to that 64.2%, which is provided by batch mode using the same adsorbent. The results of this study offer a basis to use as main capable adsorbents for the efficient elimination of phenol and 4-chlorophenol from wastewater.