Simultaneous Removal of Pollutants from Aqueous Solutions using Biochar

Abstract

Inorganic and organic pollutants have considerable effects on the ecosystem and human health. Current conventional wastewater treatment technologies are not effective at removing these trace contaminants and are complex, time consuming, expensive or involve toxic sludge disposal. Additionally, low-cost treatment systems utilizing locally available materials to treat polluted groundwater are necessary as groundwater is primarily consumed in under-developed regions. This investigation aimed to improve understanding of the use of low-cost and sustainable adsorbents in the removal of inorganic and organic pollutants. Biochar has potential to adsorb contaminants and is cheaper than activated carbon as the economic assessment indicates. Since date palm waste was not used as feedstock for biochar widely, it was aimed to characterize the structure of date palm waste-derived biochar, particularly the fronds and leaves pyrolyzed at 400, 500 and 600 °C via scanning electron microscopy, energy dispersive X-ray, Fourier transform infrared spectroscopy, X-ray diffraction, elemental (CHNS) and Brunauer-Emmett-Teller analysis. Furtherly, batch and fixed-bed studies were utilized to determine the adsorption kinetics and dynamics to remove heavy metals (copper, iron, nickel, zinc and manganese), phosphate, ammonium, nitrate and other inorganics in aqueous solutions. Isotherms-Langmuir, Freundlich and Temkin and kinetic models- pseudo-first-order, pseudo-second-order and Elovich were used to fit the experimental data from the batch studies while the Thomas and Adam Bohart models were used for the column-derived data. Using the most optimum conditions, the best performing adsorbent was applied to synthetic primary/secondary wastewater and synthetic groundwater mimicking borehole conditions in Ghana. Phenol removal was also studied as it can be toxic at low concentrations; response surface methodology with Box-Behnken design was used to optimize the factors (pH, dosage and contact time) involved in its adsorption. This investigation indicates the effectiveness of date palm waste-derived biochar for the removal of inorganics and phenol from aqueous solutions and synthetic wastewater/groundwater.

Date of Award	Dec 2022
Original language	American English
Supervisor	Banu Sizirici Yildiz (Supervisor)