KEMAMPUAN FOTOKATALIS KOMPOSIT POLIVINIL ALKOHOL/TITANIUM DIOKSIDA (PVA/TiO2) PADA KONDISI ASAM

Ani Rohmatillah, Dr. Sc. Ari Dwi Nugraheni, S.Si., M.Sc , Dr. Eng. Ahmad Kusumaatmaja, S.Si., M.Sc

2019 | Skripsi | S1 FISIKA

Telah berhasil dibuat membran fotokatalis nanofiber PVA/TiO2 4/1 dan 4/1,5 dengan metode elektrospining. Nanofiber di-crosslink GA untuk menjaga kestabilannya di dalam cairan. Nanofiber diuji swelling dan fotokatalis dengan variasi pH larutan 1, 2, 4 dan 7 kemudian diuji SEM. Pada penelitian tersebut menunjukkan bertambahnya kandungan TiO2 pada komposit PVA/TiO2 mengakibatkan diameter nanofiber meningkat. Pengujian swelling menunjukkan rasio swelling meningkat seiring dengan menurunnya nilai pH dan waktu konstan (tau) meningkat seiring dengan meningkatnya nilai pH. Hasil uji fotokatalis menunjukkan kemampuan fotokatalis semakin meningkat seiring meningkatnya nilai pH, sehingga kurang sensitif terhadap asam. Hasil uji swelling dan fotokatalis yang berlawanan tersebut karena mekanisme pendegradasian TiO2 dalam pH lebih dominan dibanding sifat sensitif nanofiber terhadap pH. Nanofiber 4/1 hanya mampu mendegradasikan sebanyak 18,1% dalam pH 2 MB selama 2 jam, sedangkan nanofiber 4/1,5 hanya mampu mendegradasi sebanyak 4% saja dengan waktu yang sama. Penambahan TiO2 pada komposit PVA/TiO2 menyebabkan rasio swelling dan kemampuan fotokatalis menurun.

Nanofiber photocatalytic membranes of PVA/TiO2 4/1 and 4/1,5 have been done using electrospinning method. Glutaraldehyde crosslinking agent was added to increase membrane stability in water. The nanofiber membranes were tested for their swelling behaviour and photocatalytic activity in various pH solutions of 1, 2, 4 and 7 that were then characterised with SEM. The results indicated that increasing TiO2 in the PVA/TiO2 composites will result in the increase of the diameter of the nanofibers. Swelling ratio tends to increase with the decrease of pH of the solution and time constant (tau) tends to increase due to increasing pH solutions. Photocatalytic test indicated that the photocatalytic activity increase with increasing pH solutions. This implies that both nanofiber membranes were not sensitive in acidic condition. The Swelling and photocatalytic activity results have no correlation since degradation mechanisms of TiO2 in various pH solutions played a more substatial role than the acidic properties of the nanofiber membranes. Nanofiber 4/1 obtained a dye removal percetage of 18,1% in pH 2 with 2 hours photocatalyctic light exposure and nanofiber 4/1,5 obtained only 4% under the same conditions. The addition of TiO2 in the composite causes swelling and photocalyctic dye removal to decrease.

Kata Kunci : PVA, TiO2, swelling, fotokatalis, nanofiber