Study and meta-analysis on petrochemical wastewater treatment by biochar modified with eggshell as adsorbent

Petrochemicals (sometimes abbreviated as petchems) are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as maize, palm fruit or sugar cane. The two most common petrochemical classes are olefins (including ethylene and propylene) and aromatics (including benzene, toluene and xylene isomers). Aromatics are produced by catalytic reforming of naphtha. Olefins and aromatics are the building-blocks for a wide range of materials such as solvents, detergents, and adhesives. Olefins are the basis for polymers and oligomers used in plastics, resins, fibers, elastomers, lubricants, and gels. Petrochemicals are large and complex chemical products derived from natural gas and petroleum, releasing monoethylene glycol (MEG) to the natural environment (e.g., water bodies). Monoethylene glycol (MEG; formula HO–CH۲–CH۲–OH) is an essential chemical product used to manufacture polyester fiber, bottles, and film. It is also required to reduce the risk of gas hydrate formation during hydrocarbon transportation. Petrochemical industrial wastewater laden with MEG is characterized by poor biodegradability, high toxicity, and carcinogenicity. In addition, petrochemical effluents pose serious threats to human health, including damages of the brain, eyes, kidneys, and nervous system; or even death at high doses. They also tend to deteriorate the environment and ecosystems; hence, removing MEG from the aquatic environment is of great importance. Previous studies have attempted to eliminate MEG from aqueous solutions via the adsorption process using activated carbon and Zr-metal organic frameworks. These studies have revealed that adsorption would be a promising and cost-effective approach for the treatment of wastewater containing MEG. Adsorption is a simple and environmentally friendly technology that has found relevant results, regarding energy utilization, sludge disposal issues, and operation and maintenance costs. In comparison, the biological systems used for the treatment of industrial wastewater containing ethylene glycol entail a retention time over ۱۲ h. The long hydraulic residence time leads to large reactor volumes and initial investment costs. Moreover, the chemical treatment of petroleum wastewater requires advanced reactions and processes, and it utilizes large amounts of reagent and raw material. Furthermore, the membrane technology suffers from high energy consumption, fouling and scaling problems, and complex production and control procedures. In this study, the pyrolysis of sewage sludge was employed to prepare a biochar (BC) adsorbent that was modified using eggshell wastes, obtaining eggshell-modified biochar (EMBC).

کلیدواژه ها:

Oil price ، Stock market ، NARDL ، South Asia ، Efficient market hypothesis ، Asymmetry