The functionalization of surface charges on oil palm empty fruit bunch (EFB) fibers was modified by grafted carboxylic
acid and polymer amine groups. Single and binary adsorption of Cu(II), Ni(II), Mo(VI) and As(V) were investigated
by competitiveness in the adsorbents. The mechanism of each metal ion was deliberately studied on kinetics-diffusion
(intraparticle diffusion) and isotherm adsorption models (Langmuir and Freundlich). Competitiveness of metal ions was
found in the selectivity of Cu(II) > Ni(II) and Mo(VI) > As(V) in the binary solution. The regeneration of adsorbents
was performed up to five cycles of an adsorption/desorption process and the reduction of adsorption performance was
less than 14.5%. Therefore, this promises low-cost adsorbents for metal ion uptake, showing potential for removal and
recovery in industrial wastewater treatment.
In this study, magnetic cellulose membranes (MCM) have been prepared by using cotton linter as cellulose source and NaOH/urea as cellulose solvent at different magnetite content. Cellulose was dissolved in pre-cooled NaOH/urea solvent at -13°C to form cellulose solution. The cellulose solution then was mix with magnetite (Fe3O4) nanoparticles synthesized via co-precipitation method of Fe2+ and Fe3+ in the presence of sodium hydroxide (NaOH) to form MCM. The MCMs formed at different percentage of Fe3O4 i.e., 10, 20 and 30%. Analysis from vibrating sample magnetometer (VSM) shows that the saturation magnetization of the MCM increase as the percentages of Fe3O4 nanoparticles increased. However, the addition of Fe3O4 nanoparticles in the regenerated cellulose membrane has decreased the crystallinity index of MCM. The surface morphology of the MCM showed that the Fe3O4 nanoparticles were dispersed in the pore of the membrane. Tensile test showed decreasing in the tensile strength of the cellulose membrane with the addition of Fe3O4 nanoparticle.
In this study, graphene oxide (GO), produced using the simple Hummer’s method, was used as adsorbent to remove methylene blue (MB) from aqueous solution. Characterizations using transmission electron microscope (TEM) and Fourier transform infrared (FTIR) spectroscopy were carried out on the GO before the MB adsorption experiments. The adsorption kinetics and isotherm studies were conducted under different conditions (pH = 3-7 and MB concentration = 100-400 mg/L) to examine the adsorption efficiency of the GO towards MB in aqueous solution. The adsorption kinetics data were analyzed using different kinetic models to investigate the adsorption behavior of MB on GO. The obtained results showed that the maximum adsorption capacity of the GO towards MB can achieve up to ~700 mg/g for the adsorption at 300 mg/L MB. The adsorption kinetic data were found to fit pseudo-second order model as compared with pseudo-first-order model. The intraparticle diffusion model suggested that the adsorption process of GO towards MB was dominated by the external mass transfer of MB molecules to the surface of GO.
Membran selulosa terjana semula (MS) daripada pulpa teras kenaf telah berjaya dihasilkan menggunakan kaedah pra penyejukan dan digumpal menggunakan larutan asid sulfurik. MS disediakan daripada pelarutan selulosa kenaf dalam larutan akues NaOH/urea dan larutan selulosa seterusnya digumpal dengan H2SO4 pada kepekatan 5-12 peratus berat (% bt.) selama 1-10 min. Pengaruh kepekatan penggumpal H2SO4 dan masa penggumpalan ke atas struktur, saiz liang, sifat mekanik dan ketelusan cahaya MS telah dikaji menggunakan pembelauan sinar-X (XRD), imbasan mikroskop elektron tekanan boleh ubah (VPSEM), penguji regangan dan spektrofotometer ultra-violet sinar tampak (UV-vis). Keputusan VPSEM menunjukkan perubahan saiz liang membran bergantung kepada kepekatan larutan penggumpal H2SO4, manakala masa penggumpalan tidak mempengaruhi saiz liang membran. Membran yang direndam dengan larutan penggumpal pada kepekatan 10 % bt. dan masa pembekuan yang sederhana iaitu 5 min menunjukkan sifat mekanik yang lebih baik dengan nilai kekuatan regangan masing-masing 41.9 dan 43.5 MPa. Oleh itu, kajian ini dapat memberikan maklumat mengenai penyediaan MS dengan pelbagai saiz liang dan sifat mekanik dengan pengubahsuaian kepekatan dan masa penggumpalan.
Absorption is one of the effective, simple and economical methods to remove oil from oily wastewater. The most widely
used approach is to utilize lignocellulosic biomass as oil absorbent. However, the hygroscopic of cellulose have limited
the oil-water separation capability of lignocellulosic fibers. In this study, the surface functionality of oil palm empty
fruit bunch (EFB) fibers was slightly altered by grafting reduced graphene oxide (rGO). The modified EFB fibers show
a distinct morphological and chemical characteristics changes as the surface of fibers has been coated with rGO. This
was supported by FTIR analysis with the diminishing peak of hydroxyl group region of EFB fibers. While the surface
modification on EFB fibers shows a diminution of a hydrophilic characteristic of 131.6% water absorption in comparison
with 268.9% of untreated EFB fibers. Moreover, modified fibers demonstrated an oil-water separation increment as well,
as it shows 89% of oil uptake and improved ~17 times of oil selectivity in oil-water emulsion than untreated EFB fibers.
Struktur-nano TiO2 dengan pelbagai saiz dan bentuk telah disintesis melalui kaedah hidrotermal menggunakan serbuk nanozarah TiO2 sebagai prekursor. Sistem hidrotermal yang mudah, murah dan bebas templet pada suhu rawatan 180ºC, pengaruh medium alkali dengan penambahan NaOH dan KOH ke atas saiz, morfologi dan sifat fotovoltaik struktur-nano TiO2 telah dikaji. Sampel telah diperincikan oleh mikroskopi elektron transmisi (TEM), analisis penyebaran tenaga sinar-x (EDAX) manakala keupayaan fotovoltaik sel suria sensitif pewarna (DSSC) diukur menggunakan Gamry Potentiostat Series G-300. Hasil kajian dengan menggunakan agen alkali yang berlainan (NaOH dan KOH) jelas mempengaruhi morfologi TiO2 dan sel suria sensitif pewarna yang terdiri daripada struktur nanorod TiO2 menunjukkan keupayaan terbaik dengan voltan litar terbuka (Voc) sebanyak 416.8 mV, ketumpatan arus litar terbuka (Jsc) sebanyak 0.169 mA/cm2 dan kecekapan penukaran (η) sebanyak 0.0232% di bawah iluminasi lampu xenon AM 1.5.