Surface Modification of Polyethersulfone Membrane via Uv-Grafting for Forward Osmosis Technology

Abstract

In this study, UV-grafting was used in surface modification of polyethersulfone membrane (UFPES50) for forward osmosis (FO) application. Using two parameters, namely monomer concentration (acrylic acid) and grafting time, the modified membrane was characterised by attenuated total reflectance-Fourier transform infrared (ATR-FTIR), field emission scanning electron microscope (FESEM) and contact angle. The membrane was evaluated for its water permeability, solute permeability, and structural parameter. The water permeability increases as the grafting parameters increases; however, at the highest (50 g/L) of monomer concentration, a sudden drop occurred due to the thickening of the grafted layer. Focusing on this monomer concentration, the grafting time was increased up to 60 minutes and it was successfully demonstrated that the modification using UV-grafting on PES membrane involved both effective grafting and chain scission. In addition, negative rejection on the modified membrane was observed.Keywords: forward osmosis, effective grafting, negative retention, structural parameter Abstrak Di dalam kajian ini, kaedah cantuman UV digunakan untuk mengubah membran polyetersulfon (UFPES50) untuk kegunaan aplikasi osmosis ke hadapan. Dua parameter digunakan iaitu kepekatan monomer (asid akrilik) dan masa cantuman. Pencirian bagi membran yang telah dimodifikasi dilakukan melalui spektroskopi transformasi infra merah Fourier-pantulan keseluruhan dikecilkan (ATR-FTIR), mikroskop imbasan elektron pancaran medan (FESEM) serta sudut sentuhan. Membran telah di nilai dari segi ketelapan air, ketelapan bahan larut dan struktur parameter. Ketelapan air meningkat dengan pertambahan percambahan parameter, tetapi pada kepekatan monomer yang tinggi (50g/L), telah berlaku perubahan yang mendadak. Dengan memberi fokus kepada kepekatan ini, masa cantuman ditingkatkan sehingga 60 minit. Hasil kajian berjaya membuktikan bahawa proses cantuman meliputi cantuman berkesan dan pemotongan rantaian. Selain daripada itu, di dapati terdapat penolakan negatif pada membran yang telah diubah suai.Kata kunci: osmosis ke hadapan, cantuman berkesan, penolakan negatif, struktur parameter Introduction Access to clean water is crucial for all human being. As a result, advancement in water treatment technology is necessary. In the quest for a technology that can achieve better efficiency, longer life-cycle, limited operating area, as well as low capital and operating expenditure, forward osmosis (FO) was the breakthrough in replacing the conventional reverse osmosis (RO) process. In the FO process, it employs the natural osmotic pressure as its main