The present study was to investigate the use of granular activated charcoal (GAC) as a potential material for removal of toxic aliphatic compounds by adsorption. Commercial granular charcoal was degassed at 105°C, 300°C and 800°C for a period of twenty-four hours, which was then used as an adsorbent for the adsorption of methylamine, dimethylamine and trimethylamine from their aqueous solutions at 25°C. The time dependence studies showed that four hours are the optimum time for the maximum adsorption of the alkylamines, irrespective of their nature and concentrations (0.005M & 0.01M). Adsorption was greater from higher concentration than lower concentration of adsorbate solution. Lower adsorption of alkylamines was observed when the charcoal was evacuated at high temperature. The adsorption sequence of alkylamines followed the order dimethylamine > trimethylamine > methylamine. The amount of adsorption using different adsorption isotherm, i.e. Freundlich and Langmuir were evaluated. L-type isotherms were also observed for the adsorption data. Further, the Langmuir and Freundlich isotherms were found applicable to the adsorption data and the values of the adsorption capacity i.e. "k" and monolayer adsorption capacity "b" were calculated and in agreement with the adsorption patterns.
[Kajian dilakukan untuk melihat kegunaan arang teraktif granul sebagai bahan berpotensi untuk mengeluarkan sebatian alifatik toksik dengan jerapan. Arang granulat komersial dinyahgas pada 105°C, 300°C dan 800°C untukj angka masa 24 jam dan seterusnya digunakan sebagai penjerap bagi jerapan metilamina, dimetilamina dan trietilamina dari larutan akueus pada 25°C. Kajian kebergantungan masa menunjukkan bahawa masa optimum untuk jerapan maksimum alkil amina ialah 4 jam, tidak kita bentuk dan kepekatan (0.005M & 0.01 M). Pencapaian jerapan adalah lebih tinggi pada kepekatan tinggi dibandingkan dengan larutan jerap berkepekatan rendah. Jerapan rendah oleh alkilamina diperhatikan apabila arang dinyahgas pada suhu tinggi. Susunan jerapan alkilamina diperhatikan apabila arang dinyahgas pada suhu tinggi. Susunan jerapan alkilamina mengikut tertib dimetilamina > trimetilamina > metilamina. Amaun jerapan menggunakan isoterma jerapan berbeza, iaitu Freundlich dan Langmuir telah dinilai Isoterma jenis juga diperhatikan untuk data jerapan. Tambahan pula, isoterma Freundlich dan Langmuir didapati berguna untuk data jerapan dan nilai kapasiti jerapan, iaitu 'k' dan kapasiti jerapan lapisan mono dihitung dan didapati konsisten dengan corak jerapan].
Biochar/layered double hydroxide (LDH) composites have gained considerable attention in recent times as low-cost sustainable materials for applications in water treatment. This paper critically evaluates the latest development in applications of biochar/LDH composites in water treatment with an emphasis on adsorption and catalytic degradation of various pollutants. The adsorption of various noxious contaminants, i.e., heavy metals, dyes, anions, and pharmaceuticals onto biochar/LDH composites are described in detail by elaborating the adsorption mechanism and regeneration ability. The synergistic effect of LDH with biochar exhibited significant improvement in specific surface area, surface functional groups, structure heterogeneity, stability, and adsorption characteristics of the resulting biochar/LDH composites. The major hurdles and challenges associated with the synthesis and applications of biochar/LDH composites in water remediation are emphasized. Finally, a roadmap is suggested for future research to assure the effective applications of biochar/LDH composites in water purification.
In this research work, a novel hybrid composite consisting of biochar (B), layered double hydroxide (CuFe) and chitosan (CS) (B-CuFe-CS) was produced using an ultrasonication-assisted co-precipitation method. The resultant composite was employed for adsorptive removal of Eriochrome black T (EBT) from water. Physicochemical characterization indicated that the B-CuFe-CS containing 10 wt % CS exhibited a heterogeneous structure with better crystallographic and textural characteristics. The B-CuFe-CS with abundant surface functionalities (-CO, -C-O, -OH, -NO3, and MMO), facilitates faster and enhanced removal of the EBT. The kinetic results showed better fitting to the pseudo-second order model, and equilibrium was achieved within 30 min. Equilibrium data was well explained by Langmuir and Redlich Peterson isotherm models (R2 > 0.98), indicating the EBT removal onto B-CuFe-CS followed monolayer adsorption. The maximum adsorption capacity was 806.4 mg/g, which was higher than pristine B-CuFe (476.19 mg/g) and many other adsorbents. The spectroscopic analysis (FTIR and XPS) and experimental results suggested that EBT adsorption is mainly governed by electrostatic, chemical and anion-exchange interactions. It is evident from these results that coupling B-CuFe composite with bio-filler (chitosan) resulted in an efficient bio-adsorbent to effectively purify dye-contaminated water streams.
Bacteria blight is one of the most serious bacterial diseases of rice worldwide. The identification of genetic potential against bacterial blight in the existing rice resources is a prerequisite to develop multigenic resistance to combat the threat of climate change. This investigation was conducted to evaluate alleles variation in 38 Malaysian cultivars using thirteen Simple Sequences Repeats markers and one Sequence Tagged Sites (STS) marker which were reported to be linked with the resistance to bacterial blight. Based on molecular data, a dendrogram was constructed which classified the rice cultivars into seven major clusters at 0.0, 0.28 and 0.3 of similarity coefficient. Cluster 5 was the largest group comprised of ten rice cultivars where multiple genes were identified. However, xa13 could not be detected in the current rice germplasm, whereas xa2 was detected in 25 cultivars. Molecular analysis revealed that Malaysian rice cultivars possess multigenic resistance.
A phytochemical investigation on the ethyl acetate soluble fraction of Lonicera quinquelocularis (whole plant) led to the first time isolation of one new phthalate; bis(7-acetoxy-2-ethyl-5-methylheptyl) phthalate (3) and two new benzoates; neopentyl-4-ethoxy-3, 5-bis (3-methyl-2-butenyl benzoate (4) and neopentyl-4-hydroxy-3, 5-bis (3-methyl-2-butenyl benzoate (5) along with two known compounds bis (2-ethylhexyl phthalate (1) and dioctyl phthalate (2). Their structures were established on the basis of spectroscopic analysis and by comparison with available data in the literature. All the compounds (1-5) were tested for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities in dose dependent manner. The IC50 (50% inhibitory effect) values of compounds 3 and 5 against AChE were 1.65 and 3.43 µM while the values obtained against BChE were 5.98 and 9.84 µM respectively. Compounds 2 and 4 showed weak inhibition profile.