Date of Award

12-2005

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Fahmi Abu AI-Rub

Second Advisor

Dr. Mohammed Abdulkarim

Third Advisor

Dr. Jiaping Paul Chen

Abstract

The recent rapid increase in industrialization activities contributed to most of aquatic pollution problems. Among aquatic pollutants, heavy metals, such as zinc, lead, cadmium, and copper have gained relatively more significance in view of their persistence and toxicity. Due to their health and toxicological effects, environmental agencies and authorities have set strict regulations to maintain the limit of heavy metals in wastewater below the maximum acceptable concentration levels.

The technical feasibility of using raw date pits and different activated carbons prepared from date pits by air and acid activation as low cost local adsorbents for the removal of different heavy metals from aqueous solutions was investigated. The effects of solution pH, time, adsorbent amount, concentration of heavy metals, and the presence of other pollutants on the adsorption capacity were studied.

The experimental results showed that adsorption capacities of and cadmium and zinc on the date pits and prepared activated carbons were highly pH dependent. Zinc or cadmium adsorption by the raw date pits at the optimum pH values was found to be rapid where maximum uptakes were occurred within the first thirty minutes. On the other hand, the equilibrium uptakes of these metals on the prepared activated carbons were attained within the first hour. The equilibrium data for the adsorption of zinc or cadmium ions onto all adsorbents used in this study could be adequately fitted to the Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich (D-R) isotherm equations. Dynamics studies showed that adsorption of zinc and cadmium ions on the date pits and prepared activated carbons followed pseudo-second order kinetics. The presence of salts such as sodium chloride, EDT A, or citric acid was found to decrease zinc or cadmium uptake on the adsorbents studied. The presence of both metals in aqueous solutions suppressed the removal of each metal significantly.

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