Enhancing anti-scaling resistances of aromatic polyamide reverse osmosis membranes using a new natural materials inhibitor

The anti-scaling properties of green additive seeds were used as a novel environmentally friendly on the precipitation of calcium sulfate (gypsum) scale on the reverse osmosis (RO) in desalination plants. Initial screening of many additives included: Ginger extract, Pepper extract, Lysine, and Glutamic amino acid have been carried out. The effect of additives was evaluated by measuring calcium ions remained in the solution, and their performance that was comparable with the blank supersaturated calcium sulfate solution. The formation of the gypsum crystals has been verified using XRD and SEM analysis. It can be seen that the degree of inhibition of gypsum scale in the presence of these inhibitors is in the following order: Ginger extract > Pepper extract > Lysine > Glutamic at different concentrations (25,50,100 ppm). A concentration of 100 ppm Ginger extract led to be superior to others with an inhibition 98.80%. The SEM images of the collected precipitates when green inhibitors were added as a scale inhibitor, and were compared with that of the blank solution. The effect of Ginger extract (gypsum) scaling on selected reverse osmosis (RO) membrane surfaces was observed in the extent of surface scale coverage and surface crystal size among the membrane studied.