Water polluted by pharmaceuticals, metals, and phosphates can be hazardous to both the environment and human health. The main aim of this study is to develop low cost, green adsorbents for removal of these pollutants from aqueous solution as a low cost alternative to activated carbon. Biochar was produced from the fast pyrolysis of Douglas fir. Magnetic biochar was prepared by magnetite (Fe3O4) precipitation onto the biochar’s surface from an aqueous Fe3+/Fe2+ solution upon NaOH treatment. Both Douglas fir and magnetic Douglas fir biochars have high uptake and adsorption capacity. Chapter I provides an overview of different biochar production techniques and modification methods. Chapter II is a study of the aqueous adsorption of pharmaceutical products, 4-nitroaniline (4NA), salicylic acid (SA), benzoic acid (BA) and phthalic acid (PA) using Douglas fir and magnetic Douglas fir biochar. The surface chemistry and composition of the magnetic biochar were examined by SEM, SEM-EDX, TEM, PZC, XPS, XRD, elemental analysis, and surface area measurements. Chapter III describes the removal of lead and cadmium using both magnetic and nonmagnetic Douglas fir biochar and Chapter IV describes the removal of phosphate from waste water. In Chapter V, this low cost adsorbent (magnetic Douglas fir biochar) was introduced into an undergraduate laboratory to expose students to water quality issues and methods of contaminant removal enhancing their understanding of these important environmental issues. This experiment introduces new and interesting approaches to water purification as well as deepens the student’s understanding of present environmental concerns regarding pharmaceutical contaminants in wastewater.

Molybdenum (Mo) is a naturally occurring trace element that is present in drinking water mostly in the molybdate (MoO42-) form in well water. Recently, the EPA deemed Mo as a potential contaminant because exposure can lead to health effects such as gout, hyperuricemia, and lung cancer. In this work, we have assessed the sorptive removal of Mo using Douglas fir biochar (DFBC) and its chemically-coprecipitated iron oxide analogue (DFMBC). Adsorption was studied varying the batch sorption conditions; pH, equilibrium time (5 min-24 h), initial Mo concentrations (2.5-1000 mg/L), temperatures (5, 25, and 40 °C) and equilibrium method. Langmuir capacities for DFBC and DFMBC (at pH 3, 2 h equilibrium) were in 359.3-487.9 mg/g and 288.3-571.9 mg/g range, respectively. Adsorbents and Mo-laden adsorbents were characterized by elemental analysis, BET, PZC, SEM, TEM, EDS, XRD, and XPS. These data suggest that DFBC and DFMBC can be potential candidates for Mo sorption.

The biochar-bentonite clay hybrid was prepared by coprecipitation with the goal of producing a material that can remove Pb (II) from aqueous solutions effectively. Incorporating bentonite clay onto the Douglas fir biochar (DFB-BTC) surface significantly improved the adsorption capacity by introducing more active sites, strengthening the structural properties, and promoting strong adsorbate interactions. The point of zero charge of the adsorbent was slightly higher than that of the pristine DFBC. All sorption experiments were performed at pH 5, and the system obeyed the Langmuir adsorption isotherm. The highest Langmuir adsorption capacities observed at 298, 308, and 318 K were 48, 80, and 78 mg/g, respectively, with 99.85% as the highest removal efficiency. The sorption kinetics showed that equilibrium was reached after 2h for both 5 and 50 mg/L Pb(II) solutions, whereas equilibrium was attained after 4h for 100 mg/L, which fit a pseudo-second-order model. The surface characterization was determined using scanning electron microscopy (SEM), X-ray diffraction (XRD), BET, and FTIR. This study aimed to develop a facile, eco-friendly, versatile, low-cost, and hybrid biochar-bentonite clay (BBC) for an exhaustive evaluation of Pb (II) uptake in water.