الفهرس 
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Abstract
The present work studied the control of pentachlorophenol (PCP) as a model of chlorination disinfection by-products in drinking water. Locally prepared date-pit activated carbon (DPAC) used as an adsorbent of pentachlorophenol. Effect of contact time, initial concentration, temperature (25-55°) and pH (2-11) were studied. Equilibrium modeling has been carried out using Langmuir, Freundlich, Temkin and Redlich-Peterson isotherms. Mass transfer and kinetic study for the adsorption of PCP onto DPAC using slurry batch adsorber, with mechanical stirring techniques, have been investigated. Effects of different variables such as agitation speed, initial concentration, dose of carbon and temperature have been studied. At the laboratory-scale studies, the experimental results indicated that the use of a locally prepared date-pit activated carbon (DPAC) as adsorbent of pentachlorophenol (PCP) from aqueous solutions proved to be effective.
5.1 Conclusions
The following major points can be extracted from the results:
(1) Equilibrium adsorption of (PCP) onto (DPAC) at different temperature and pH values had been studied. The maximum adsorption capacity was reached to (412.5µg.g-1) and 94.72% removal efficiency at 25°C. The adsorption reaction is a physical exothermic one, and dramatically affected beyond pH 9.
(2) Equilibrium adsorption isotherms have been analyzed using, Langmuir, Fruendlich, Redlich-Peterson and Temkin isotherms. The isotherm constants were determined and ARE error function was used to select the best isotherm. The Langmuir isotherm was found to be the best to fit the experimental data compared to other isotherms based on the error function values and graphical presentation.
(3) Temperature plays an interesting role in the adsorption of PCP onto DPAC. The adsorption capacity of DPAC for PCP was decreased from 300.3(µg.g-1) and 97.5 % to 179.45 (µg.g-1) and 57.92% with increasing temperature from 15 to 55 °C. This show that the adsorption processes is exothermic for the adsorption of PCP onto DPAC.
(4) Mass transfer data extracted from the experimental results have been analyzed using external mass transfer and intraparticle diffusion models. The external mass-transfer has been studied with four design variables, namely agitation speed, initial PCP concentration, temperature, and DPAC mass. The external mass-transfer coefficient (Ks) has been determined and used to correlate experimental data against the design variables. The overall adsorption process of PCP onto DPAC was found to be controlled by external mass transfer in the early stage of adsorption process followed by intraparticle diffusion until process reach equilibrium.
(5) Intraparticle diffusion for the adsorption of PCP onto DPAC has also been studied and the macropore rate parameter (KI) has been determined and used to correlate experimental data against the design variables.
(6) The kinetic data extracted from slurry batch adsorber with mechanical stirring have also been analyzed using pseudo first-order and pseudo second- order models. The results show that the experimental data for the adsorption of PCP onto DPAC follows pseudo second- order model for all variable studied based on graphical presentation, and correlation coefficient values.
5.2 Suggestions for further work
The investigation presented in this thesis is based on isotherm and kinetic studies for the adsorption of PCP onto a locally prepared date-pit activated carbon (DPAC) and still needs further studies for a routine application in the treatment of water contaminated with disinfection by-products and for other engineering purposes. There are several points that may be taken into consideration for further work.
To study two-resistance and three-resistance mass transfer models and correlate the mass-transfer coefficients (KS, Deff) with the geometry of adsorber, properties of solid particles and the dynamic conditions.
To study the use of commercial adsorption systems such as fixed-bed column and fluidized bed column; a series of pilot-scale studies would be beneficial for the scale up of the adsorption process.
Integrated environmental management for the mass production of activated carbon from date pits, is required. The integrated management includes study of the environmental impact of the manufacturing process and developing sustainable waste management by reduce, reuse or recycle of the by-products and outcomes.