Prediction of Metal Remobilization from Sediments Under Various Physical/Chemical Conditions "Design of Experiment for As &Ni"

Date of Award

8-2015

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Chemistry

First Advisor

Eid Alkhatib, Ph.D.

Abstract

The greatest threat that face our water supply is heavy metal contamination. Therefore, this makes it a vital task to understand remobilization mechanism of different heavy metals, under different conditions. Different meltals [sic] have different solubility. In this case, the metal partition coefficient Kd (L/kg) is used in describing the ratio of the sorbent metal concentration on solid state, m (in milligrams per kilograms), in reaction to the dissolved metal concentration on equilibrium. The resulting metals are affected by various factors that are interconnected. Nevertheless, the influential process is hard to determine. The major factors that influence the specification and partitioning of metals are the organic matter and their concentration in the sediments, the pH, and salinity. This paper will look into the partitioning of Arsenic (As) and Nickel (Ni), which are transtion [sic] metals. Therefore, different experiments will be conducted to investigate the effect of the different levels of pH, salinity, and organic matter content concentration. The three levels of organic matter are tested against five levels of pH and salinity; the design of experement [sic] was generated by MiniTab16. From the results, it was noticed that the partition coefficient increased with increase in pH up to 7.2, after which there is a rapid increase in the partition coefficient. This was derived from the experiment due to the formation of precipitates showing the presence insoluble metal hydroxide. Also to this a high dependence of Kd on the organic compounds was also observed. From the analysis of the results using MiniTabl6® regression analysis was performed and multiple regression equations that were, generated to predict Kd of both metals. The equations indicated that the methodology can be used to illustrate the relationships between the factors under investigation and Kd, furthermore, it can be used to point out unexpected symptoms in the system. On the contrary, this methodology had some drawbacks that need tackling in future experiment.

Comments

Master's thesis submitted to the faculty of Sacred Heart University Chemistry Program in partial fulfillment of the requirements for the degree of Master of Chemistry.

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