Thesis (MSc) - Cyprus International University. Institute of Graduate Studies and Research Enviromental Sciences

This study investigates the efficacy of orange peel, an easily accessible and
biodegradable waste product, as a proficient adsorbent for the elimination of
methylene blue dye from wastewater. Various techniques, including BET, BJH,
XRD, FT-IR, and Point of Zero Charge, were employed to analyse the physical and
chemical attributes of orange peel. Biosorption examinations demonstrated that the
elimination of methylene blue increased with greater adsorbent mass, higher initial
solution pH, and low solution concentration. However, the sorption capacity of the
orange peel diminished with higher orange peel doses. Under optimal conditions
(pH=11, initial concentration of 30 mg/L, orange peel dose of 125 mg), a maximum
sorption capacity of 238.095 mg/g and a removal percentage of 95.019% were
achieved. Also, the desorption was found to be 73.676%. Equilibrium data aligned
well with the Freundlich isotherm, signifying the methylene blue attachment through
biosorption on heterogeneous active sites. Time-based investigations substantiated
the pseudo-second-order model, indicating chemisorption mechanisms involving
functional groups during interactions between orange peel and methylene blue. The
research underscores orange peel's potential as a cost-effective and environmentally
friendly substitute for methylene blue removal, stressing the importance of
repurposing waste products to tackle environmental challenges and encouraging
further exploration of sustainable methods for methylene blue removal.