الفهرس 
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Abstract
Preparation and characterization of polysaccharides based hybrid materials for wastewater treatment.
Polysaccharides could be use to remove undesirable substances that exist in waste water by chemical modification. The adsorption capacity of polysaccharides was improved by chemical modification such as cross linking to give composite materials that have chemical and physical features of both inorganic and organic materials
Chitosan is one of most abundant polysaccharides originated from chitin which posses amino and hydroxy functional groups, it could be enhancement the properties of chitosan in chemical and thermal stability, hardness and other properties. Compination of chitosan with silica was improved adsorption performance by addition the features of silica into superior material, chitosan and use these hybride as template for metal oxide nano particles. Using zinc oxide nano particle is helpful in forming promising adsorbent with high affinity to act as antimicrobial agent. Also using Iron oxide such as magnetite could be improving act as adsorbent
On the other hand, cellulose is anther polysaccharide that also very abundant because it is the main structure of the plants. Nanocellulose has several features different from conventional materials, such as decrease the toxicity and biodegradability, biocompatibility, specific surface area and others. The modifications of nanocellulose are accomplished to improve the nanocellulose properties.
The presence of hydroxyl groups (-OH) expected to facilitate the modification and functionalization of nanocellulose. TEMPO cellulose (TEMPO – CNF) is derivative of cellulose able to combined with metal oxide which support its properties and enhance photocatalytic and antimicrobial properties, Zinc oxide is a promising candidate to immobilization on TEMPO – CNF and forming composites able to remove organic pollutant.
Synthetic dyes regard a major components of water pollution, which becomes a serious environmental problem. Dyes are aromatic organic substance, and the colour of dye is provided by the presence of a chromophore group that consisting of conjugated double bonds containing delocalized electron. Basic dyes are cationic dyes that have a positive charge on their molecules. Methylene blue is an important cationic basic dye that has common used for many industries that causes several diseases to humans and animals.
A conventional biological treatment process is not enough to remove the dyes from waste water. Adsorption has many advantages compared to other techniques for waste water treatment as flexibility, initial cost, easy to operation, simple in design and handling to toxic pollutants. Adsorption techniques have high performance to remove the pollutants which are hardly treated with traditional biological methods.
Beside adsorption the removal of dye by oxidation methods is promising technique to eliminate organic carbons as dyes. Photo degradation of dyes by semiconductors effluent treatment is a significant process due to it’s a quick and has powerful capacity in addition to not give secondary pollutants, this study aims to producing different polysaccharides based hybrid materials for waste water treatment to achieve:
1- Best use for absorption of Methylene blue
2- Best use for oxidative organic dye as Methylene blue model by solar photocatalysis.
3- Form hybrid composites in nanoscale which have antimicrobial effect.
4- Reduce cost and increase performance of waste water treatment.
The current study includes:
1- Synthesis of chitosan/silica:
Combination of chitosan with Tetraethoxysilane (TEOS) to form hybrid and the synthesized hybrid affirmed by FT-IR, and thermal analysis
2- Synthesis of Chitosan/Silica/Metal Oxide
Chitosan/silica immobilized by Zinc Oxide (ZnO) and magnetite (Fe3O4) to form nanocmposites compounds, the synthesis of these compounds is affirmed by a range of analytical techniques: FT-IR, , XRD, SEM,TEM and thermal analysis.
3- Application of synthesized nanocmposites
a- Anti-microbial screening
The anti-bacterial activity of the synthesized compounds was tested against Gram- negative and Gram-positive bacteria using nutrient agar medium.
b- Adsorption study
The adsorption studies were performed using batch method technique, to study the effect of pH, contact time and adsorption capacity of chitosan/silica/ZnO and chitosan/silica/Fe3O4 toward Methylene blue (MB)
Langmuir equation was found to have the highest value of R2 compared with freundlich model. Furthermore, it was found that the synthesized nanocmposites have a high adsorption capacity towards MB. Langmuir and Freundlich and were used to simulate the equilibrium data. The adsorption capacity of chitosan/silica/ZnO and chitosan/silica/Fe3O4 are 293.3 and 285 mg/g respectively for MB dye in slight basic medium and show favorable adsorption with separation factor (RL < 1). In addition, pseudo-first- order and pseudo-second order were used to study the kinetics of MB adsorption on Chitosan/silica/ZnO and Chitosan/silica/Fe3O4 respectively. Adsorption process undergoes pseudo-second order kinetic as proved by the high value of R2.
c- Determination of Chemical Oxygen Demand (COD) reduction
According to a Standard Methods for the Examination of Water and Wastewater 21st Edition, COD reduction is one of most important parameter to evaluate the performance of waste water treatment via determine the amount of organic pollutant in effluent by using COD.
The contribution of pH to the COD reduction was investigated at pH 7 and the maximum results were achieved by applying contact time 120 min. were 72 %, 95 % and 88 % for chitosan/silica and chitosan/silica/ZnO and chitosan/silica/Fe3O4 respectively.
4- Synthesis of TEMPO - CNF:
The chemical modifications of cellulose was obtained through 2, 2, 6, 6-tetramethylpiperidinyl-1-oxyl (TEMPO)-mediated oxidation to form TEMPO-CNF
The formation is confirmed by FT-IR, and thermal analysis.
5- Synthesis of TEMPO-CNF/ZnO
Zinc Oxide (ZnO) was immobilized on TEMPO-CNF and the synthesized compound confirmed by a range of analytical techniques: FT-IR, UV, band gap, XRD, SEM and thermal analysis.
6- Application of TEMP-CNF/ZnO
a- Anti-microbial screening
The anti-bacterial activity of the synthesized compounds was tested against Gram- negative and Gram-positive bacteria and fungi using nutrient agar medium
Photocatalytic activity
Methylene blue (MB) was chosen as a model dye for testing the photocatalytic activity of TEMPO-CNF/ZnO using batch method technique. The solution was stirred under dark conditions for 90 min to achieve the adsorption-desorption equilibrium and then irradiated by visible light for 340 min.
The degradation rate was gradually increased with increase in pH and the degradation of MB dye solution reached to 86% within 340 min in case of utilizing TEMPO-CNF/ZnO at pH 7
In addition, pseudo-first- order and pseudo-second order were used to study the kinetics of photocatalytic process and the results showed that the pseudo- first order kinetic best fitted the photocatalaytic process.