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Abstract

This work involved the production and thermal characterization of biomass briquettes produced by blending a major agricultural waste with coal dust. In the work, nine different compositions of coal dust/groundnut husk briquettes were produced using starch as the binder while Ca(OH2) was incorporated as the de-sulphurizing agent. The ash content, volatile matter, fixed carbon, moisture content, compressive strength, ignition time, calorific value, water boiling test and burning rate were carried out to determine the physical, mechanical and thermal properties of the briquettes produced. The results showed that moisture content values are in the range 2.43 - 6.44%, for compressive strength 7.72 - 10.85 N/mm3, for ash content 24.18 - 29.15 %, for calorific value 21714.17 - 25027.18 kJ/kg, for fixed carbon 16.77-53.22 %, for ignition time 22.23-45.20 s, for water boiling test 1.50-4.99 min and burning rate 16.10-28.32 g/min. These are appreciable values for the thermal properties of the bio-briquettes. Therefore, the agro-wastes briquettes are beneficial for heating purposes rather than open incineration of the wastes.

Abstract

New organotin (IV) complexes with NaL1 (sodium salt of 2-[[4-(3-methoxy-propoxy) -3-methylpyridin-2-yl]methylsulfinyl]benzimidazol-1-ide) and NaL2s (sodium salt of 3- aminomethyl-5-methylhexanoic acid) were synthesized by the reaction of diorganotin (IV) and triorganotin (IV) salt (Bu3SnCl, Ph3SnCl, Bu2SnCl2, Me2SnCl2) using the solvent (dry toluene) by constant stirring and refluxing. All the organotin (IV) complexes were characterized by different diagnostic techniques such as FT-IR (Infra-red) and UV-visible spectroscopy. The results exhibited that ligand NaL1 (sodium salt) is attached to tin metal by a nitrogen atom of benzimidazole ring and the oxygen atom of the sulfonyl group. While ligand NaL2 (sodium salt) coordinate with tin(IV) moiety through oxygen atom of the carboxylate group. The newly synthesized complexes 1 & 2 of ligand NaL1 (sodium salt) showed trigonal bipyramidal geometry while complexes 3 & 4 octahedral geometry around tin(IV) centre. The organotin(IV) complexes 5-7 of ligand NaL2 (sodium salt) have the tetrahedral geometry around tin(IV) centre. The synthesized complexes (1-7) were tested for antifungal and antibacterial microbial activities. All the complexes showed significant antibacterial and anti-fungal activities against tested bacterial and fungal strains.

Abstract

Studies on the adsorption of Pb(II) on plantain peels biochar (PPB) was conducted. The carbonized and activated, biochar was characterized using Braunauer-Emmett-Teller (BET) surface area and x-ray diffraction crystallography (XRD). BET analysis of the PPB indicated that the pore size (cc/g) and pore surface area (m2/g) was 8.79 and 16.69 respectively. Result of the XRD evaluated through Debye-Scherrer equation, showed a nanostructure with crystallite size of 14.56 nm. Effects of initial metal ion concentration, pH, and contact time were studied in a batch reaction process. Results showed that the adsorption of lead from aqueous solution increased with an increase in pH and initial concentration. Equilibrium modeling studies suggested that the data fitted mainly to the Langmuir isotherm. Adsorption kinetic data tested using various kinetic models fitted the Weber and Morris intraparticle diffusion model implicating pore diffusion as the main rate limiting step. The sorption studies indicated the potential of plantain peel biochar as an effective, efficient and low cost adsorbent for remediating lead (II) ions contaminated environment.

Abstract

Momordica cochinchinensis, or Gac fruit belongs to Cucurbitaceae family. Although this species is considered to be native in Southeast Asia especially in Vietnam, Thailand and Laos, it is still contemplated as a rare and new fruit species in Malaysia. Availability of this species is very limited in Malaysia hence, the raw material for researches is also in short supply. Currently, Gac fruit is utilized as traditional food, health supplements, food colouring and juices. Gac fruit was discovered to have high value pharmaceutically and economically as it had been recognized as a rich source of bioactive compounds. On that account, this study aimed to generate preliminary data on the morphological characterisation and phytochemical composition which focused on β-carotene and lycopene content of Gac fruit aril. This data could be useful for further researches particularly on breeding improvement of Gac fruit. The morphological characterisation was mainly based on both vegetative and reproductive parts of the plant. Both β-carotene and lycopene content of aril was analysed and estimated using UV-Vis Spectroscopy technique. The aril was extracted using mixed solvent of n-hexane 95%, ethanol 99.9% and acetone 99% with ratio of 2:1:1 v/v/v. Furthermore, morphological data of root, stem, leaf, flower, fruit and seeds were also successfully recorded. Besides that, the β-carotene and lycopene content obtained were 0.117 ± 0.011 mg/g FW and 0.021 ± 0.002 mg/g FW, respectively. Discrepancy in the results might be due to numerous factors like collection sites, level of maturity at harvest, storage and processing conditions, analysis techniques and type of solvent extractors used that might have affected the quality and contents of the carotenoid. Several suggestions for extension of this study had been propounded so that the benefits of this species could be exploited in the best possible ways.

Abstract

Immobilization of enzymes is a good field of study to extend the life of enzyme and reduce the cost of the chemical processes, such as separation processes. Urease is an important enzyme with medical and industrial applications. The aim of the present study is to prepare an immobilized urease on a strong cation exchange resin (Amberlite IR120 Na) and study its activity and stability. We monitored the release of Na ions in the collected fractions and searching for enzyme in the fractions as indicators of immobilization by ion exchange phenomenon. Sodium is determined by using atomic absorption spectroscopy technique, while the enzyme concentration was tested by Bradford’s method. Immobilized urease activity was evaluated by salicylate-hypochlorite method. The results indicated a complete immobilization of urease enzyme on the resin surface with reserving 92% of the activity of free enzyme. The immobilized urease enzyme on resin showed good stability and it has a 62% of its activity after 154 days of storage at room temperature. It is concluded that a new immobilized urease enzyme system is prepared with good enzyme activity and stability.

Abstract

Starch is acryloylated and copolymerised without incorporating any vinyl monomer such as acrylic acid or acrylonitrile monomers to produce a superabsorbent copolymer. Fenton’s initiation system was used to produce polyacryloylated starch ester with varying degree of substitution. The copolymer from starch ester exhibited improved solubility, and an impressive water, saline, and solvents uptake. The superabsorbency of the samples is affected by the number of acryloyl groups on starch backbone. The starch ester with degree of substitution 0.8 had the highest water absorbency (102 g/g) in this experiment. Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetric (TGA) analyses were used to characterize the products.

Abstract

Tartaric acid is generally not an effective soil washing solution, hence this study focuses on enhancing its usage for soil-Pb decontamination. Three tropical soil types (sandy, clay and loamy) with different lead concentrations were subjected to single batch washing using 0.01, 0.1, 0.5 and 1 M tartaric acid with 5% and 10% KCl modification at 3% soil-pulp-density for 2, 6, 12 and 24 h washing time. The optimum washing conditions were 1 M tartaric acid at 24 h washing time, with Pb removal efficiency: sandy- 94.3%, clay-67.6% and loamy-36.8%. Modification of tartaric acid with 5% and 10% KCl brought about some degree of enhancement of Pb removal efficiency especially for clay and loamy soils. Removal efficiency for 5% KCl modification were: sandy-97.9%, clay-96.2% with 1 M tartaric acid at 24 h washing time, loamy-76.7% for 0.5 M tartaric acid. Similarly, 10% KCl modification were: sandy-96.7%, clay-97.2% for 1 M tartaric acid at 24 h, loamy-82.1% for 0.5 M tartaric acid. Removal efficiency was soil concentration dependent. Generally, removal efficiency increased with increasing tartaric acid concentrations and washing time. Tartaric acid washing is promising and recommended in events of moderate contamination and 10% KCl modification in event of high level contamination. Further study is needed on enhancing very low concentrations of tartaric acid for large scale applications.

Abstract

The objective of this work was to compare the extraction of phenolic compounds from Tilia argentea flowers and bracts by using conventional (solvent extraction) and novel (ultrasound assisted) extraction methods. Ethanol (70 %) extracts were analyzed for their antioxidant activities. Total phenolic content was determined using Folin-Ciocalteu method and the antioxidant potential was determined by DPPH radical scavenging and Ferric Reducing Antioxidant Power (FRAP) assays. To determine the effect of ultrasound treatment on the extraction, same extraction parameters were applied in both methods. The results showed that extracts obtained by ultrasound assisted extraction have higher total phenolic content and antioxidant activity.

Abstract

Chromatographic separation of methanolic extract of Baphia nitida heartwood gave two crystalline solids characterized as 3,9-dimethoxy-6aR,11aR-dihydro-6H-benzofuro(3,2-C)[1]benzopyran (also known as homopterocarpin) with molecular formula C17H16O4 (1.57% yield) and 2,4-dimethoxybenzaldehyde C9H10O3 (2.27% yield). Each of the isolated compounds showed a single spot on developed thin layer chromatographic plate under ultra-violet light (254 nm) and spray reagent (10% sulfuric acid in methanol solution). Structural elucidation was achieved using Fourier transform infrared (FT-IR) spectroscopy, one and two-dimension nuclear magnetic resonance (NMR) techniques. Distortionless enhancement by polarization transfer-edited-heteronuclear single quantum coherence (DEPT-ed-HSQC) was also a useful tool that aided the characterization of the two secondary metabolites isolated from Baphia nitida heartwood.

Abstract

In the present study, some 2- and 3-substituted piperidin-4-ones (A1-A3) were chosen as proton acceptor and maleic anhydride was chosen as proton donor. Piperidin-4-ones (A1, A2 ---amp--- A3) were mixed with maleic anhydride in ether medium and the corresponding molecular adduct products (B1, B2 ---amp--- B3) thus obtained were collected and purified. The 1H and 13C NMR spectra were recorded for piperidine-4-one and their addition compounds. The 1H and 13C NMR chemical shifts of products (B1, B2 ---amp--- B3) are analyzed and compared with those of the corresponding piperidine-4-ones (A1, A2 ---amp--- A3). In order to confirm the formation of molecular addition compounds the GC-Mass spectrum was recorded for all adducts B1-B3 and the fragmentations patterns were analyzed.