The Performance and Life Cycle Assessment Comparison of Pristine and Modified Biochar for the Removal of Pharmaceuticals in Aqueous Solutions

Abstract

As the global population grows, the demand for medications and pharmaceuticals increases. Consequently, pharmaceuticals consumed by humans often end up in wastewater streams and ultimately in the environment. Current wastewater treatment technologies face significant challenges in detecting and effectively removing these emerging contaminants. Biochar has demonstrated promising efficacy in removing pharmaceuticals due to its exceptional adsorption properties. This dissertation presents a comprehensive and systematic investigation into the removal of frequently occurring and widely prescribed pharmaceuticals—Acetaminophen, Atenolol, Carbamazepine, Ibuprofen, Naproxen, and Sulfamethoxazole—along with phenol using pristine biochar derived from date palm tree waste and its acid-, alkali-, and metal-modified variants. The adsorption capacities of pristine and modified biochars were evaluated using experimental techniques and statistical physics modeling, coupled with Box-Behnken Design (BBD) and Response Surface Methodology (RSM). These methods were applied to analyze the individual and interactive effects of operating conditions such as pH, adsorbent dosage, and contact time in batch studies. The results were interpreted using both linear and non-linear isotherm and kinetic models. To assess field applicability, the effects of biochar bed depth, flow rate, and influent concentrations were examined in continuous fixed-bed column studies in the presence of competing ions. Surface morphology, elemental composition, functional groups, and mineral content of biochar before and after adsorption were characterized using Scanning Electron Microscopy (SEM) with X-ray Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FT-IR). The environmental sustainability of pristine biochar versus modified biochars (from production to delivery to wastewater treatment plants) was assessed using Life Cycle Assessment (LCA) in SimaPro software. A cost-benefit analysis was also performed to evaluate the economic feasibility of biochar production and its application. The results indicate that modified biochars exhibit higher adsorption capacities for pharmaceuticals due to improved pore structures and increased adsorption sites. However, LCA revealed that modified biochars have a significantly higher environmental impact, with a Cumulative Energy Demand (CED) of 143.22 MJ/kg and a Global Warming Potential (GWP) of 10 kg CO2 equivalent. Sensitivity analysis suggests that transitioning to renewable energy sources could reduce greenhouse gas emissions by 37.4% and CED by 22.1%.

Date of Award	7 May 2025
Original language	American English
Supervisor	Mutasem El Fadel (Supervisor)