الفهرس 
Introduction and Literature SurveyOnly 14 pages are availabe for public view
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Abstract
Industrial waste water effluents dyes have a serious destructive impact on our ecology system. The polymer based materials have versatile applications in all aspects of our life. Thus the main objective of the thesis was to prepare high performance nanocomposites based on acrylic fibers waste (AF) as matrix and nanochitosan (NCh) for remediation of Congo red (CR) dye by adsorption method. Also to be utilized as a tight ultrafiltration membrane for CR and Crystal violet (CV) dyes removal. Firstly the nanochitosan (NCh) was prepared using ionic gelation method by drooping TPP into chitosan diluted acetic acid solution. The nano chitosan powder got separated and characterized using FTIR, TEM and DLS. The characterizations techniques revealed a successful preparation of NCh of average size round 100 nm. To prepare AF-NCh membranes for the adsorption process with different ratios of NCh (0, 10, 20, 30, 40, 50 & 60 wt. %), we adopted the phase inversion techniques. Briefly a predetermined weight of AF was dissolved in DMF at 70 °C, then NCh was inserted and the blended solution got stirred and sonicated to get homogenous composites solution. The composites membranes were casted in a glass plate, then immersed in a water coagulation bath for 24 h. The resulted films of 0.20 mm thickness were evaluated for adsorption of CR from aqueous solution. A composite film of 50% weight ratio of NCh achieved the best %R of 98 % for 200 mg/l for CR after contact time of 4 h. Another fabricated acrylic fiber- nanochitosan using epicholorohydrin (EPH) was prepared. The two fabricated adsorbed films coded AF-NCh and AF-NCh-EPH were characterized and their performances as adsorbent for CR were evaluated. FTIR of composites films AF-NCh and AF-NCh-EPH declared that the presence of C≡N and C=O ester and their intensity were decreased comparing to pure AF and observed at 2246 cm-1, and 1738 cm-1, respectively. NH and –OH peaks are observed around 3429 cm-1. SEM images showed the surface and cross section of AF-NCh and AF-NCh-EPH, which declared the enhanced porosity and macrovoids structure. Also showed the inclusion of spherical shaped nanoparticles indicating nano-chitosan incorporation into AF matrix, which lead to increasing active sites for dye adsorption process. BET analysis of composites films declared surface area of AF film slightly decreased upon addition of NCh and NCh-EPH. This may be due to the inclusion of high content of nano-chitosan with high entangled force of these particles. But in spite of decrease the surface area of nanocomposite film but they have high adsorption capacity to CR dye compared to AF film because of presence of reactive and hydrophilic function groups such as (-OH and –NH2). Thermal stability of AF, AF-NCh and AF-NCh-EPH have been investigated and declared good thermal stability round 40% at 600 oC weight residual due to cyclisation and aromatization reaction. Also, two distinct degradation peaks resulted from the physical embedding of NCh into AF. Also inclusion of EPH as a cross linker decreased thermal stability compared to AF and AF-NCh due to lack of packing chains of composites. Adsorption studies were carried out to get the optimum condition for CR remediation process. Different parameters were employed such as, CR concentrations, adsorbent dose, effect of time and pH. Langmuir, Freundlich isotherms and kinetic studies evaluations were applied. Results declared that, the maximum adsorption capacities of AF-NCh and AF-NCh-Epichlorohydrin were 166.6 and 232.5 mg/g, respectively. The adsorption isotherm and kinetic mechanism obey Langmuir and pseudo second order models. Regeneration of the synthesized composite films were studied for five cycles and showed relative stable performance with high efficiency.
In the second part of this thesis acrylic fibers waste blended with different ratio of nanochitosan with low percent ranged [0.5, 1, 2 and 4 wt.%] were fabricated into ultrafiltration nanocomposites membranes by phase inversion method for removal of CR and CV dyes. The prepared membranes were characterized by FTIR, XRD, TGA and SEM in addition to contact angle and water uptake.
XRD showed a characteristic peak of AF at 17.6 °. Upon blending process the geometry nature of AF blended with nanochitosan is changed and two new peaks appears at 15.2° related to AF matrix and a small broad peak at 25.6° related to nanochitosan
TGA study showed that the thermal stability of the prepared composite membranes was decreased by increasing the nanochitosan ratio This may attributed to the acceleration degradation process of AF membranes at a higher % nanochitosan that decreased the packing density and orientation of AF polymeric chains.
SEM study revealed the surface and cross section of the bare AF at with different magnifications, and revealed an asymmetric structure comprising a porous thin layer and a much thicker porous sub-layer containing finger-like macrovoids (the large elongated pores). The inclusion of nanochitosan as indicated by the spherical shape structure of AF-NCh (4%) resulted in a change in membrane morphology.
The membrane surface hydrophilicity was estimated using contact angle measurements that revealed the highest hydrophilic nature were in order 4 %, 2%, 1%, 0.5% and bare AF loaded nanochitosan. Also porosity, water content and pure water flux were measured for nanocomposite membranes which revealed enhanced porosity, PWF upon inclusion of NCh. Membranes performances were tested for CR as anionic dye and CV as cationic dye at variant concentrations 20, 30 and 40 mg/l of both dyes and variant applied pressures ranged from 1 to 4 bar. The experimental results declared the promising performance of the nanocomposites molecular sieves for high removal efficiency of CR ranged round 100 %. Compared to CR, CV has a low molecular weight thus the %R through the prepared molecular sieves ranged from 100 to 67 % depending on the % loading of nanochitosan, applied pressure and the CV dye concentration. Finally compared to previous published studied, the prepared ultrafiltration AF-NChs could be a candidate membrane prepared from polymer waste with low cost for dyes removal.