Description
ABSTRACT
The released heavy metal from refinery effluents into the environment is a world major concern. Different studies have demonstrated that natural agents have high adsorption capacities for divalent metal ions. Coconut shell is a natural adsorbent and in comparison with others and its availability in Nigeria, is cost effective. In this study, the adsorption of heavy metals (Pb and Cu) from effluent water was investigated in batch condition. Activated carbon was prepared from coconut shell, carbonized at 500 oC and impregnated with 1.0 M HCl at 700oC in a muffle furnace for 2 hr. The resultant products were tested to adsorb the heavy metals in effluent water at varying pH, dosage and contact time. The adsorption capacity and metal removal percentage was computed and recorded at the various varying parameters in the study; while the reaction attained equilibrium in 2 hr contact time. The maximum Pb removal efficiency was 78% at pH of 5.5 at a contact time of 1.9 hr and the maximum Cu removal from the effluent was 97% at pH of 5.6 and a contact time of 2 hr.
TABLE OF CONTENTS
COVER PAGE
TITLE PAGE
APPROVAL PAGE
DEDICATION
ACKNOWELDGEMENT
ABSTRACT
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
- AIM OF THE STUDY
- OBJECTIVE OF THE STUDY
- SCOPE OF THE STUDY
- PROJECT ORGANISATION
CHAPTER TWO
LITERATURE REVIEW
- THEORETICAL FRAMEWORK
- OVERVIEW OF WASTEWATER TREATMENT
- WASTEWATER TREATMENT PLANTS
CHAPTER THREE
- MATERIALS AND METHODS
- MATERIALS
- METHODS
CHAPTER FOUR
- RESULT AND DISCUSSION
- RESULT
- DISCUSSION
CHAPTER FIVE
- CONCLUSION
- RECOMMENDATION
- REFERENCES
CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Wastes containing different dyes and hydrocarbons compounds are often found as pollutants in industrial wastewaters and effluent gases such as discharged in aqueous effluent from dye-stuff manufacturing, refineries, dyeing and textile industries. Early uses of activated carbon were reported from water filtration and for sugar solution filtration. Activated carbon’s ability to remove a large variety of compounds from contaminated waters had led to its increased use in the last thirty years. Recent changes in water discharge standards regarding toxic pollutant have placed additional emphasis on this technology. The demand for activated carbon is increasing owing to the increased utility of the carbon materials in environmental pollution control (Sricharoenchaikul et al., 2007). As a result, the cost of activated charcoal is growing depending on the application. Designing methods for the production of activated carbon in more economic ways is the need of the hour. A range of low cost, easily available, carbon rich and low ash precursor and sources are thus being explored for the production of activated carbon.
Most of the commercial activated carbons are either coal based or petroleum pitch based which are prone to exhaustion. As the applications of activated carbon are immense, the gap between demand and supply is ever widening. This may in due course result in scarcity of the material in addition to becoming expensive. This situation necessitates the exploration of new sources of carbon materials with desired physical and chemical properties (Sricharoenchaikul et al., 2007). The advantage of using inexpensive natural resource as raw materials for manufacturing activated carbon is that these raw materials are renewable and potentially less expensive to manufacture (Rezaee et al., 2008). A lot of research works have previously been done on activated carbon to improve its application. One of the fast growing areas is in environmental applications such as wastewater treatment. In the treatment of wastewater, it is used for purification, discoloration and the removal of toxic organics and heavy metals ions (Nurul’Ain, 2007).
There has been an increasing interest in the production of activated carbon from agricultural by-products and industrial waste (Rahmani et al., 2009). Agricultural wastes such as cocoa pod husk (Rahman et al., 2006), periwinkle shell (Aluyor and Badmus, 2008), walnut shell, peach stoner, physic nut waste, coconut shells, palm kernel shells, and bamboo stem wastes (Awoyale et al., 2012) have been used in the production of activated carbon thereby adding value to these agricultural wastes and thus recycling them.
Activated carbon is one of the most popular adsorbents used in numerous industries for the removal and recovery of organic and inorganic compounds from gaseous and liquid streams. It has high adsorption capability due to its high internal surface area and porosity formed during carbonization process. The presence of activating agents and carbonization conditions influenced the development of pore structures (Rahman et al., 2006). Typically, the preparation of activated carbon can be divided into two processes. First, physical method consists of the pyrolysis of the precursor material and gasification of the resulting char in steam or carbon (IV) oxide. The formation of the porous structure is achieved by elimination of a large amount of internal carbon mass. High porosity carbons can be obtained only if a high degree of char is burn off. For the chemical method, pyrolysis char would be impregnated with some chemical reagents, such as ZnCl2, H3PO4, NaOH and KOH (Sricharoenchaikul et al., 2007).
In this research, activated carbon was prepared from locally obtained Nigerian agricultural waste, coconut shell using HCl and H3PO4 as activating agents with a view to preparing, characterizing and investigating the adsorption effectiveness of the activated charcoal produced there- from as compared to the activated charcoal prepared from bamboo in one of our earlier studies.
1.2 AIM OF THE STUDY
The aim of this work is to prepared activated carbon from locally obtained Nigerian agricultural waste, coconut shell using HCl and H3PO4 as activating agents with a view to preparing, characterizing and investigating the adsorption effectiveness
1.3 OBJECTIVES OF STUDY
The objectives of this work include:
- Characterization of wastewater generated at the refinery,
- Evaluation of the current treatment process performance
- Design, development and evaluation of alternative treatment processes compatible with project resources.
- Laboratory scale tests on the most promising treatment process with a view to improve the current process and enable recycling of wastewater for uses required by the end user.
The project involves visits to the refinery to collect process data and wastewater samples for analyses. At some stage, wastewater treatment process simulation would play a major role in the advancement of the project, using real plant data from the refinery wastewater unit and physical/chemical characteristics of its wastewater.
1.4 SCOPE OF THE STUDY
The scope entails the production and evaluative efficiency of the activated charcoal from Nigerian cocoa coconut shell in the selective adsorption of industrial waste water (refinery effluents); carbonization of the washed shell and adsorption experiment which will be conducted in two stages: first, determining the effect of different concentrations of the activating agent on adsorption; and second, comparing efficiency with commercial activated carbon.
1.5 PROJECT ORGANISATION
The work is organized as follows: chapter one discuses the introductory part of the work, chapter two presents the literature review of the study, chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.
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