Pollution Control

Due to rapid urbanization, climate change, industrial activities, and improper managements, access to clean water is threatened with time. Phenols are classified to be one of the most hazardous pollutants found in industrial wastewater that contributes significantly to water pollution. Activated carbon fibers (ACFs) of high surface area are developed from Polyacrylonitrile (PAN) and compared with other granular activated carbon materials. The PAN fibers were stabilized initially followed by carbonization either by physical (carbon dioxide) or chemical (potassium hydroxide) activation. The stabilization, carbonization and activation conditions such as flow rate, temperature, time and dosages were optimized. The synthesized ACFs as well as the intermediate materials were characterized using Scanning Electron Microscopy(SEM), Energy-DispersiveX-raySpectroscopy(EDS),Thermogravimetric Analysis (TGA) and Carbon, Hydrogen, Nitrogen and Sulphur content (CHNS) methods. The synthesized ACFs with highest surface area as well as commercial ACFs (C-ACFs) were evaluated for p-cresol removal from water and later applied for produced water treatment. The results showed that ACF, produced by chemical activation (Syn-ACF) using 3:1 by weight KOH: carbonized fiber produced, have very high surface area (2885 m2/g) compared to the ones produced by physical activation (774 m2 /g) and exceed by far those reported in the literature using KOH. The adsorption study on Syn-ACF gave a higher removal efficiency of 90.0% of p-cresol in comparison with 71.6% using commercial C-ACFs at challenge concentration of 350 ppm. In addition, the adsorption isotherms of p-cresol on C-ACFs and Syn-ACFs were measured and found to fit well using Langmuir isotherm; however, Syn-AFCs revealed higher Qmax=500 mg/g compared to C-ACFs Qmax=294 mg/g at 25°C. Regeneration of the contaminated Syn-ACFs with p-cresol was done using two methods: thermally at 600°C and chemically with n-Hexane achieving removal efficiency of 84% and 78%, respectively. The adsorption study using the Syn-ACFs was completed using produced water to ensure a removal of 71.2%.