Abstract
M.Sc. (Chemistry)
The scarcity of clean and accessible water has become a global obstacle. This is specifically alarming for a dry country like South Africa where, for example, the average level of major dams in the Western Cape was only 36.1% on 27 November 2017. Since 10% of a dam’s water cannot be extracted, thus, about 10% of the actual dam level non-usable. Another growing concern in South African water systems is the presence of numerous inorganic pollutants and organic pollutants, including persistent organic pollutants (POPs). Of all the water users, agriculture consumes about 70% of all freshwater thus water shortages and the presence of various pollutants may greatly affect the food production process.
Inorganic pollutants are usually of mineral origin and include heavy metals like lead, cadmium, chromium and arsenic. Arsenic, one of the most toxic heavy metal pollutants found in water originates from both natural sources and human activities. Prolonged exposure to arsenic can cause various health problems including different forms of cancer. Arsenic often concurs with several POPs in water as well.
Persistent organic pollutants are synthetic organic pollutants which have low solubility in water and due to their lipophilic nature, they tend to have a great affinity for fat-rich tissues. One of the most problematic POPs is polychlorinated biphenyls (PCBs). Health effects caused by PCBs include endocrine disruption, defects in the immune, reproductive and nervous systems as well as cancer.
Conventional water and wastewater treatment methods such as coagulation-flocculation and biological methods have shown certain limitations towards complete removal of arsenic (more specifically As(III)) and PCBs, especially at trace levels. This has urged researchers to formulate superior methods that can successfully remove arsenic and PCBs from water.
This study therefore employed membrane technology modified with a hyperbranched polyethyleneimine (HPEI) to firstly remove arsenic(III) from synthetic and spiked tap water. The incorporation of HPEI in membranes assists in the encapsulation of heavy metal during water treatment. Characteristic amine and amide bands in the FTIR-ATR spectra confirmed the successful incorporation of HPEI on the...