STUDIES ON ACTIVATED BIOCHAR FOR ADSORPTIVE REMOVAL OF MODEL CONTAMINANTS OF PETROLEUM REFINERY WASTEWATER

Abstract

Water pollution is a global problem arising mainly due to anthropogenic activities towards achieving rapid economic development. Industrial wastewater effluent is the major source of environmental pollution, and chiefly comprises diverse organic and inorganic contaminants. Surprisingly, 80% of the estimated wastewater generated globally is discharged into the natural water-bodies. The petroleum industry is a prominent wastewater source and contains metal ions, hydrocarbons, organic compounds, and complexes, which are generally toxic and persistent pollutants. Wastewater or effluent from oil refinery cannot be directly discharged to a tailing pond due to its detrimental effect on flora and fauna. It requires various treatments before re-use or final disposal. Full compliance of lawsuits and the different guidelines of regulatory bodies are necessary for the disposal of effluent. In the light of local and global law, wastewater needs treatment to remove pollutants up to a certain level before final disposal. Wastewater may become a considerable useful resource for repurposing use after proper treatment. Various technologies like electrochemical treatment, photochemical degradation, and microbial remediation are available to treat wastewater. But the adsorption techniques are more viable than other technologies due to ease of operation and low operational cost. In this context, activated carbon is widely used to treat wastewater, mainly in the polishing step. However, activated carbon is expensive, and hence, there is a need to develop low–cost adsorbents for water treatment. Biomass from agricultural residues can be utilized for converting to several valuable resources. This will not only reduce the unnecessary consequential environmental problem due to open-air burning, but the lignocellulosic biomass can be converted to bio-oil, biochar, and gaseous products by pyrolysis. Compared to as-prepared biochar, surface treated or activated biochars are valorized. The post-treated biochar can act as an adsorbent to remove various pollutants from wastewater. The hypothesis is to convert the lignocellulosic biomass to an efficient adsorbent for tertiary treatment of petroleum refinery wastewater. It is a link between biorefinery and petroleum refinery. By converting biomass to an adsorbent, it can solve the problem that arises from biomass burning and provide an alternative to activated carbon.