Grafting of poly(acrylamide) onto crosslinked poly(HEMA-co-MMA) resin for removal of phenol and bisphenol A

Phenol and its substituted derivatives are widely found in the effluents from pesticides, synthetic rubber, plastic, pharmaceuticals, petrochemicals, and other industries. It is also used in the production of caprolactam and bisphenol A. They are intermediates in the manufacture of nylon and epoxy resins, respectively. It is primarily used in the production of phenolic resins, which are needed in the automotive plywood, construction and appliance industries. Other important uses of phenol are as a disinfectant and in medicinal products. Minor uses of phenol contain the manufacture of paint and varnish removers, lacquers, paints, rubber, ink, illuminating gases, tanning dyes, perfumes, soaps and toys Phenol and phenolic compounds are generally considered as one of the important organic pollutants discharged into the environment causing unpleasant taste and odor of drinking water. Even at very low concentrations in the presence of water, is undesirable and toxic to the aquatic beings including fish. Especially, chlorinated phenols are more toxic to aquatic life. Phenols have great risk to the human health and cause negative effects on the brain, digestive system, heart, eye, liver, kidney, lung, peripheral nerve, skin and the unborn child. 0.002 mg L-1 is the permissible limit for phenol concentration in potable water according to the World Health Organization regulation. Removal of phenolic pollutants in aqueous solutions can be divided into three main categories: chemical, physical and biological treatment. Several wastewater treatment methods for removal of phenolic pollutants have been used including membrane filtration, advanced oxidation, biological degradation, photocatalytic degradation, electrochemical oxidation and adsorption. Adsorpsion is very important method to remove organic and inorganic pollutants. Different adsorbents such as zeolites, carbon nanotubes, polymeric sorbents and clay have been investigated for the removal of phenol and phenolic pollutants from wastewater. Three mechanisms of phenolic compounds adsorption is postulated namely, π-π dispersion interaction, electron-donor acceptor complex formation and hydrogen bond formation. This methodology was used to prepare new polymeric sorbents for phenol removal. In this thesis, two types of polymeric sorbents were prepared for removal of phenol and BPA from water. The poly(HEMA-MMA-EGDMA) terpolymer were prepared by using suspension polymerization method starting from polymerization of hydroxyethyl methacrylate (HEMA) (50%), methyl methacrylate (MMA) (40%) and ethylene glycol dimethacrylate (EGDMA) (10%) as crosslinkerin the presence of toluene as porogen and AIBN as an initiator (resin 1). Other polymeric resin was prepared grafting polymerization of poly (acrylamide) onto resin 1 by redox polymerization method. Grafting reaction is carried out through the hydroxyl groups on HEMA units. The resulting polymer resin2 , which had a total nitrogen content of about 7.0 mmol/g, was effective in extracting phenol from aqueous solutions.The phenol and BPA sorption capacities were found depending on concentration and pH. Also, phenol and BPA sorption kinetics of the resins were investigated. Kinetic models were applied for Resin 1 and Resin 2.