removal of dye from waste water using poliathia logifolia as activated carbon

Description

CHAPTER ONE

INTRODUCTION

BACKGROUND OF THE STUDY

Water pollution is considered to have major contributions in environmental pollution and is the most dangerous form of pollution (Wang et al., 2016). Among many other sources of water pollution, wastewater that is generated by industrial processes is considered to be the major source. Organic content, heavy metals, and harmful dyes are major constituents of the wastewater (Yadav et al., 2014). Textile industry is considered as major contributor of wastewater pollution. The processes that are carried out in textile industries are responsible for the production of liquid effluents in huge amounts. These liquid effluents have both organic and inorganic constituents in it. When the fabric is subjected to dyeing, every dye is not retained on it. Such dyes, not retained firmly on the fabric are present in liquid effluents in large quantities (Yadav et al., 2014). Most commonly this is the case with reactive dyes that retain less on the fabric and are more soluble in water. In this way, enormous amounts of colored liquid effluents are generated from textile industries. These colored liquid effluents make their way to the water bodies and pollutes them. Azo dyes are mostly utilized in textile industries. If make their way to the soil, these dyes affect attributes of soil by interfering with its physico-chemical properties. Wastewater generated by textile industries consists of a wide variety of different dyes. It also has a high chemical oxygen demand (COD), biological oxygen demand (BOD), total dissolved solids (TDS), and total suspended solids (TSS). Thus, it is highly toxic and injurious to health and wellbeing of human beings as well as environment (Wong et al., 2018).

Methylene Blue (MB), a cationic dye, is used for the purpose of dyeing fabric. Exposure to MB can cause cyanosis, sweating, headache, chest, and abdominal pain in human beings (Wong et al., 2018). Alizarin Red S (ARS, Sodium Alizainsulfonate), an anionic dye, preferably used by the textile industry for the development of deep red color in the fabric. It has a ring structure due to which it is not degraded naturally and resistant to biological and thermal treatments. Some of the harmful toxicological effects like headaches, lungs malfunctioning, gastritis, methemoglobinemia, etc., are encountered if exposure to the wastewater containing ARS occurs in human beings (Wong et al., 2018). Due to such side effects it is important to treat waste water prior to its release into the waterways.

To date no literature is available on the use of chemically modified P. longifolia branches as an adsorbent for the adsorption of dyes. So the present study is focused on the utilization of chemically modified P. longifolia branches for the adsorption of dyes. P. longifolia (Ulta Shokh) is an ornamental plant having long and columnar shaped branches (Timothy et al., 2019).

The main objective of this study was to investigate the potential of chemically modified biomass of P. longifolia branches for the adsorption of dye from wastewater generated at lab scale. The modified and unmodified material was characterized by Fourier transformation infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The dependence of dye uptake from aqueous solution was also investigated over various experimental factors such as adsorbent dosage, time of con- tact, initial solution concentration, pH, and temperature. Adsorption of dyes onto the adsorbent surface was also studied using mathematical models (adsorption isotherm, adsorption kinetics, and adsorption thermodynamics).

1.2     PROBLEM STATEMENT

Various techniques had been used for the treatment of wastewater and liquid effluents generated by textile industries, for the removal of dyes, including oxidation, treatment with hydrogen peroxide, use of fenton’s reagent, solvent extraction process, and electro- coagulation method. But some problems are associated with the application of such methods such as non-feasibility from economic point of view, problem of waste disposal after treatment, use of chemicals and electricity consumption (Rajasulochana et al., 2016). Also, these methods are not environmentally sound. So, there is a need of technology that is economically feasible and at the same time ecofriendly too. In this way, adsorption can be taken into consideration. Biosorption is a physicochemical technique that involves the use of bio- mass for the removal of dyes from liquid effluents generated by textile industries (Mundhe et al., 2012). In this process Polyalthia longifolia leaves as well as seeds were used.

 

1.3      AIM AND OBJECTIVES

Present study is aimed at the synthesis and use of Polyalthia longifolia for the removal of dyes from liquid effluents generate.

The objectives of this work are:

1. To carryout an experiment on the removal of dyes from waste water using Polyalthia longifolia
2. To prepare activated carbon by using various raw materials. Activated carbon served as the adsorbent in order to remove dye

• To study the quality treatment procedures for the removal of dissolved organic pollutants like dyes from industrial waste water.

1.4      SCOPE OF THE STUDY

The scope of this work covers investigating the potential of chemically modified biomass of P. longifolia branches for the adsorption of dye from wastewater generated at lab scale.

1.5      RESEARCH QUESTION

1. How do you remove dye from wastewater?
2. Which materials are most effective method to remove dyes from water?

• What is the dye removal process?

1.6      DEFINITION OF TERMS

Activated carbon: is a form of carbon commonly used to filter contaminants from water and air, among many other uses.

Waste water: This is water that has been used in the home, in a business, or as part of an industrial process. Wastewater is water generated after the use of freshwater, raw water, drinking water or saline water in a variety of deliberate applications or processes.

CHAPTER FIVE

5.1                 CONCLUSION AND RECOMMENDATION

Biomass of P. longifolia branches was chemically modified to synthesize alumina composites which were used for the adsorption of dyes. The adsorption process was studied over various experimental factors including biosorbent dose, contact time, pH, temperature, and initial solution concentration. Equilibrium for MB and ARS was achieved at 30 and 25 min, respectively. Optimum pH values for the adsorption of MB and ARS are six and four, respectively. The equilibrium data was also evaluated by non-linear form of adsorption isotherms models (Langmuir and Freundlich) and adsorption kinetics (Pseudo-first- order and Pseudo-second-order). The equilibrium data fits best to the Langmuir model for the adsorption of MB while for the adsorption of ARS , the Freundlich model was followed. Pseudo-second-order kinetics was followed for the adsorption of both dyes. Thermodynamic parameters (Gibbs free energy, process enthalpy, and entropy change) were also estimated indicating the feasibility and endothermic nature of the reaction. The negative values of ΔG° for the adsorption of MB suggested that the adsorption pro cess is spontaneous while the positive values of ΔG° in case of ARS adsorption suggested that the adsorption process is non-spontaneous. Positive values of ΔS° and ΔH° for both dyes indicated that the adsorption process is feasible and endothermic in nature. These outcomes suggested that P. longifolia based alumina composite is environmental-friendly and cost effective biosorbent for the removal of dyes from aqueous medium.

This experiment on removal of dye from waste water using poliathia logifolia has been carried out successfully, i recommend that other methods of removal should also be used in the future research which will required the researcher comparing results.