(698c) Hydrophilic Enhancement of An Ultrafiltration Membrane through Green Chemistry

Over the past several decades we have clearly observed the repercussions of releasing toxins into the environment. Though initial focus of treating this problem concentrated on treatment of wastes before their release into environment, since 1990 authorities concentrated on the prevention of the formation of waste at the source leading to the advent of green chemistry(De Simone, 2002). The emphasis of the green chemistry aims at elimination or atleast minimization of waste generation in a chemical process through environmentally benign choices of solvents, non-toxic chemicals and renewable materials (Rajesh Kumar et al, 2004).

Commercially available water filtration membranes are usually modified by various techniques to impart the desired properties to the selective layer, thereby improving their filtration capabilities. Graft polymerization is one of those techniques widely used to attach Poly ethylene glycol (PEG) to the membrane surface. Grafting of PEG to membrane surface was proven to reduce the membrane fouling susceptibility (Torchilian et al 1995). In this project an environmentally friendly approach will be used to perform PEG grafting by minimizing the waste production by using enzymatic condensation.

Porcine pancreatic crude type II lipase, a commercially available inexpensive enzyme will be used to catalyze the PEG graft polymerization on cellulose acetate ultrafiltration membranes. This process would be an environmentally benign modification that would result in a green product through the reduction of waste stream product as well as an ability to recycle solvents and the catalyst (Brandstadt et al, 2003).

The graft polymerization reaction was performed under mild reaction conditions. A mixture containing preferred solvent, membrane samples, PEG monomer and PPL were reacted in a round bottom reaction flask containig a reflux condenser. Various solvents will be used to promote different reaction media. Solvnt free conditions was tested to see the influence of enzyme in bulk conditons. The proposed approximate solvent to monomer weight ratio is 5 and monomer to enzyme ratio is 2. Reaction was performed for 50 to 55 hrs at a temperature of 450C. Influence of various parameters such as solvent to monomer ratio, monomer to enzyme ratio, reaction time and temperature were explored.