Municipal and agricultural wastewater remediation using modified biochars

Abstract

Water contaminated by heavy metals and plant nutrients pose a threat to human health and safety as well as the environment. The aim of this body of work is to develop, characterize, and understand the adsorption properties of green sorbents to mitigate these risks. Biochar, an adsorbent known to be both environmentally friendly and inexpensive was used. Advantages of biochar are its high surface area, easy modification, and native surface functionality. Biochars used in this study are of pecan shell or douglas fir origin, although biochar can be made from a host of waste organic materials. Pecan shell biochar was modified using a simple water soaking activation technique which is totally green and free of any harsh solvents, whereas the douglas fir biochar was modified to contain both aluminum and magnesium oxides via coprecipitation of Al and Mg sulfate salts and NaOH treatment.

Chapter I provides an introduction of biochar production methods as well as a brief history of its utilization. Chapter II is a study of lead removal using biochars obtained from slow pyrolysis of dry and water soaked pecan shell biomass. In this study, water, a green and low cost reagent, was used to maximize the surface area of pecan shell biochar allowing it to adsorb more lead from aqueous solution. In this study, pecan shell biochar is analyzed using several methods including SEM, SEM-EDX, TEM, PZC, XRD, elemental analysis, and BET. Chapter III discusses the remediation of agricultural runoff water using slag and Al/ Mg modified biochar. This study characterizes both biochar and slag using various methods including SEM, SEM-EDX, TEM, PZC, XRD, elemental analysis, and BET. Chapter IV focuses phosphates in soils: An undergraduate exploration according to soil texture and amendment. The purpose of this study was to bring the cutting edge research regarding phosphate retention into the undergraduate laboratory setting.