Comparison of the Efficiency of Local Betonies and Activated Carbon for Removing of Phenol from Waste Water

Abstract

The aim of this study is the assessment of Iraqi local bentonite clay (Be) as an adsorbent for the removal of phenol from laboratory wastewater, where activated carbon (AC) was used for the same target as a conventional adsorbent under different experimental variables. Moisture content, loss of ignition (%), and FTIR tests were done to characterize bentonite clay. The batch adsorption process was carried out using AC and Be under experimental conditions with adsorbent dosage (0.1–1) g at an initial phenol concentration of 100 mg/L to study the dosage effect, while the initial concentration effect at constant adsorbent dosage was (20–100) mg/L with a dosage of 1 g of Be and (100–1000) mg/L with a dosage of 0.1 g of AC and 240 min contact time. A kinetic study of the contact time effect (15–240) min was conducted at an initial phenol concentration of 50 mg/L for Be and 250 mg/L for AC, for a constant volume of 500 mL. The results show removal percentages of 45.58% and 100% of phenol at 1 g Be and 0.4 g AC, and adsorption capacities at variable initial phenol concentrations were 1.282 mg/g and 138.31 mg/g using Be and AC, respectively. Adsorption isotherm models show good fitting with the Langmuir model for the AC/phenol system, with an R² value of 0.987 and a theoretical maximum adsorption capacity of 142.857 mg/g, while the Be/phenol system shows slightly better fitting with the Freundlich model, with an R² value of 0.981. The kinetic study shows good fitting with the pseudo-second-order model, with R² values of 0.994 for both Be and AC, which refers to chemical adsorption.