الفهرس 
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Abstract
Dyes are synthetic chemical compounds having complex aromatic structures which are extensively used in the textile, cosmetic, plastic, food, and pharmaceutical industries. Textile industry is one of the oldest industries in Egypt. Taking into account the volume and composition of effluent, textile wastewater is rated as the most polluting among all in the industrial sectors. In general, wastewater from a typical textile industry is characterized by strong color, high pH, presenting large amount of suspended solids, COD and low bio-degradable chemicals especially the effluent from the dyeing stages of the dyeing and finishing processes. The dye-containing wastewater discharged from the industries can adversely affect the aquatic environment by impeding light penetration. Moreover, most of the dyes are toxic, carcinogenic and harmful to human health. The removal of dye color is therefore a challenge to both the textile industry and the wastewater-treatment facilities. Apart from being aesthetically displeasing, they are toxic to some aquatic organisms and are of serious health risk to human beings. Thus, these synthetic dyes cause considerable environmental pollution. Therefore, there is an increasing demand of efficient and economical technologies for removing dyes from water environment in the world. Bioremediation techniques, in comparison with conventional methods are less costly, more efficient, more environmentally benign, require less energy consumption, and are less damaging to fragile ecosystems. Biosorption has been found to be one of the prominent techniques for dye wastewater treatment in terms of cost and operation. Therefore, low-cost and effective materials used for dyes removal from large volumes of wastewater have been of great concerns for environmental scientists. A wide variety of microorganisms including bacteria, fungi and algae are capable of decolorizing a wide range of dyes with high efficiency. Many current researches make systematic screening of naturally occurring microorganisms for bioremediative properties; developing a descriptive and mechanistic understanding how bioremediative and bioprocessing activities are distributed, regulated, and maintained; applying biotechnology to enhance the natural bioremediative capabilities of bacteria to remove toxic dyes and metabolize industrial wastes; and developing diagnostic tests for low-level toxic contamination. Congo red is selected in this study as a model anionic dye because of its complex chemical structure, persistence and carcinogenicity, which has been widely used in textiles, paper, rubber and plastic industries. This research aims to provide the scientific basis for introducing an eco-friendly biosorbent prepared from bacterial biomass to be used for the remediation of dye contaminated industrial effluents before disposal into the marine environment.This research is authentic in its content.
1.1. Plan of the work:
In order to realize the aim mentioned above, this work focuses on the following main tasks:
1. select a bacterial species capable of the biosorption of Congo red dye.
2. charecterization and identification of the bacterial species.
. Preparation of biosorbent material and evaluation of some factors affecting the biosorption process.
4. Surface morphology of the biosorbents determined using hanging DROP method by SEM and FTIR spectra.
5. Studying kinetics and Thermodynamics of the process and determine equilibrium isotherms.
Dye removal became a research area of increasing interest, as government legislation concerning the release of contaminated effluent has become more stringent. With this in mind, bacterial biomass was examined as a biosorbent, which is low cost, biodegradable and poses no disposal problems.