Evaluating the Catalytic Efficiency of Biochar in Wastewater Treatment Processes

Thesis Abstract

Rapid urbanization and industrialization have significantly increased the contamination of wastewater with organic pollutants, heavy metals, and emerging contaminants, presenting a critical challenge for sustainable water management. Conventional wastewater treatment methods often fall short in effectively removing recalcitrant pollutants, highlighting the need for innovative and cost-effective treatment solutions. Biochar, a carbon-rich material derived from biomass pyrolysis, has garnered attention for its potential catalytic properties that enhance pollutant degradation. However, comprehensive empirical evaluations of biochar's catalytic efficiency in wastewater treatment remain limited, necessitating systematic investigation to optimize its application for environmental remediation. This study aims to evaluate the catalytic efficiency of biochar derived from agricultural biomass in the degradation of organic pollutants and heavy metals in wastewater streams. The specific objectives include (1) characterizing the physicochemical properties of biochar produced at varying pyrolysis temperatures; (2) assessing the catalytic performance of biochar in batch treatment processes for organic dye degradation and heavy metal removal; (3) identifying the mechanisms underpinning catalytic activity using spectroscopic and surface analysis techniques; and (4) developing predictive models to quantify the relationship between biochar properties and treatment efficacy. The research hypothesizes that biochar with higher surface area and specific surface functional groups exhibits superior catalytic activity, significantly enhancing pollutant removal efficiency compared to untreated biomass. The methodology employs a mixed-methods research design integrating experimental laboratory investigations with analytical modeling. The study population comprises biochar samples produced from locally available agricultural residues, including rice husks and maize stalks, subjected to pyrolysis at 400°C, 600°C, and 800°C. A sample size of thirty biochar variants will be prepared (ten per temperature category) to facilitate comparative analysis. Data collection will utilize standardized characterization techniques such as Brunauer–Emmett–Teller (BET) surface area analysis, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) to determine material properties. Batch reactor experiments will monitor the degradation of methylene blue dye and the removal of lead (Pb²?) and cadmium (Cd²?), with pollutant concentrations measured via UV-Vis spectroscopy and atomic absorption spectroscopy (AAS). Data analysis will include statistical tests such as ANOVA to evaluate differences among biochar types, regression analysis to model relationships between biochar properties and removal efficiencies, and kinetic modeling to understand degradation dynamics. It is anticipated that results will demonstrate a clear correlation between pyrolysis temperature, biochar properties, and catalytic performance. Higher pyrolysis temperatures are expected to produce biochar with increased surface area, porosity, and functional groups conducive to catalytic activity, thereby improving pollutant removal rates by at least 30% compared to lower-temperature biochars. The study also anticipates elucidating mechanisms involving electron transfer facilitated by surface functionalities, aligned with the principles of the Electron Transfer Theory. The findings will contribute novel empirical data to the field of sustainable wastewater treatment, highlighting biochar as a viable, low-cost catalytic material with scalable benefits. The study’s primary contribution lies in advancing understanding of the relationship between biomass pyrolysis parameters, biochar properties, and catalytic efficiency in contaminant removal. It provides a quantitative framework for optimizing biochar production for tailored wastewater treatment applications. Policy recommendations advocate for the integration of biochar-based catalysts into existing treatment infrastructures, especially in resource-limited settings. Future research directions include exploring biochar modification techniques to further enhance catalytic activity and assessing long-term stability and regeneration capacity of biochar in continuous treatment systems. This research affirms biochar’s potential as a sustainable, multifunctional catalyst, addressing critical gaps in environmental remediation technology and promoting circular economy principles in wastewater management.