Performance of Modified Anaerobic Hybrid Baffled (MAHB) bioreactor treating recycled paper mill effluent: Effects of organic loading rates

The performance of modified anaerobic hybrid baffled (MAHB) bioreactor treating recycled paper mill effluent (RPME) was investigated at various organic loading rates (OLR) of 1, 2, 3 and 4 g COD/ L.day. The bioreactor was operated continuously at constant hydraulic retention time (HRT) of a day without effluent recycled and chemicals adjustment/addition. Throughout 70 days of operation, a maximum removal efficiency up to 97% of chemical oxygen demand (COD) and 98% of volatile fatty acid, biogas production of 12.51 L/day equivalent to methane (CH4) yield of 0.108L CH4/ g COD and a stable pH system between 6.6 to 7.2 were achieved. Additionally, alkalinity of the bioreactor system shows a stable profile that indicates the whole system was well buffered with a quit high degradation of volatile solid (VS) up to 18%. These results indicated that MAHB bioreactor has been successfully treated RPME at various OLR.

Synthesis and characterization of titanium dioxide doped nickel oxide dielectric materials

Nickel oxide (NiO) belongs to the transition metal oxide family, having good dielectric constantwith the range of 103 – 105, but it has high dielectric loss. In this research, the effect of titaniumdioxide (TiO2) addition into NiO was investigated. Generally, TiO2 was used in the application ofelectrical ceramic, catalysts, electric conductors and chemical intermediates. Ni1-xTixO1+x wasprepared via solid-state reaction method with 6 different TiO2 compositions. The preparation startedwith the powder mixing process for 24 hours and followed by calcination process at 950 °C for 4hours. Then, the calcined powders were compacted into 6 mm pellet shape under pressure of 250MPa pressure. Three pellets were made for each TiO2 composition. Those pellets were sintered at1250 °C for 5 hours. XRD results showed that pure NiO at 0.01 and 0.02 mole % of TiO2compositions produced single NiO crystalline phase, while 0.03, 0.05 and 0.10 mol % of TiO2showed the TiO2, instead of NiO phases. SEM analysis showed that increasing TiO2 concentrationmake the grain size increase, with 0.02 mole % of TiO2 gave the largest grain size, shows that 0.02mole % is the optimum TiO2 concentration for grain size enlargement. Furthermore, the bulkdensity of Ni1xTixO1+xpellet was reduces at higher TiO2 concentration. In dielectric test, the additionof 0.03 mole % of TiO2 gave the highest dielectric constant with value of 4.51 x 1014 and 0.05 mole% of TiO2 gives the result of lowest dielectric loss (0.53).

Phytoremediation of chromium(VI) using Colocasia esculenta in laboratory scale constructed wetlands

The existing water is becoming polluted nowadays due to high anthropogenic emission of water. The phytoremediation technology is used to treat the contaminated soil and water which containing higher amount of pollutants. The water that contains heavy metals will cause water scarcity and affect on human health when human drink the water. In this study, Colocasia esculenta was chosen for the removal of Cr(VI) in water. The efficiency of C.esculenta in accumulates Cr(VI) in synthetic wastewater was evaluated. The effect of time and concentration of Cr(VI) were identified in this study. Cr(VI) concentration was determined using diphenylcarbazide method (DPC). Experiment were set up in Laboratory Scale Constructed Wetlands with varies the concentration of synthetic wastewater of 1, 2, 5, 10, 50, 500 and 1000 mg/L and was continued for 36 days. The result of removal percentage for the 1, 2, 5 and 10 mg/L reach 100% while for 50, 500 and 1000 mg/L only remove 99.99%, 94.79% and 55.84% respectively. Roots of C.esculenta are able to accumulate Cr(VI) in wastewater which with BCF value was 1.557 mg/L. The BCF value of roots were more than 1, represents the higher accumulation of metal in plant. Therefore, C.esculenta has potential to use in removing Cr(VI) in water.

Evaluation of tendering effect from date seed extract (P. dactalytera) in knuckle part meat

Phoenic dactylifera (date) is a species of flowering plants in the family of Arecaceae. Date seeds are considered as a waste from many processing that produced plants pitted date, confectionery date syrup and date itself. Currently, the seeds are used mainly for animal feed in the cattle and chicken industry. In 2004, about 863,000 tonnes of date seeds are produced out of 6.9 million tonnes date. Tenderness is the major concern that affecting consumer acceptance of beef in meat industry. This study was carried out in order to investigate the effects of the bioactive compound extracted from date seed as a tenderizing agent in meat. Extraction of date seeds used a different method of extraction (Soxhlet and Maceration). The application of extracted on knuckle part of beef were performed and papain was used as a positive control and followed by the sensory evaluation. The analysis of cooked meat was performed in order to analyze the physico-chemical properties of date seeds extract. The result from the study revealed that the aqueous extract (maceration techniques) gave the best percentage of the total yield recovery with 28.44%. The physico-chemical properties of cooked meat showed the reducing of pH value after cooking. Meanwhile for the cooking yield, result showed that almost 86% of water losses during cooking for aqueous extract and positive control and 96% for negative control. According to the sensory evaluation of the cooked meat, scoring test and hedonic test were performed using One Way Anova. The result for texture is 6.10±2.1, juiceness is 5.87±1.76 and taste is 6.80±1.34. All attributes have no significant different at p <0.05 between aqueos extract, and positive control. A general acceptance shows that no significant different between aqueos extract (6.50±2.0) and positive control (7.13±1.98). The result suggested that the tenderization effect of date seed improved the textural properties of knuckle part meat and have potential for tenderization purpose in food industry.

Effects of core grain orientation on the mechanical properties of wood sandwich composite

Utilization of sandwich composite during recent year has been driven by the fact that compositematerial has ultimately high strength and stiffness by weight than any other materials. The skins ofsandwich composites technically bear most of the applied loads, however, the core materials alsoplay an important role as it functions in providing continuous support to resist the shear stress.Hence, proper selection of core materials is required to establish a sturdy sandwich compositestructure. This paper presents an experimental investigation on the sandwich structure consists offibreglass/epoxy face skins and a mahang wood core. Sandwich composite with core grain orientedin parallel and perpendicular to the flat plane direction were tested for mechanical performance intension, compression and flexure. The results indicate that sandwich composite with grain orientedin parallel direction performed better in tensile properties with strength of 201.98 MPa whereassandwich composite with perpendicular core grain produced a higher value of compressionproperties with strength of 70.11 MPa. However, no significant effect of grain orientation wasobserved in flexural strength. The strength of sandwich composite is dependent on the grainalignment of the wood core as it functions exclusively as mechanical supporting cells to supportthe wood structure.

Bandgap tunability from synergistic mixture of Pandanus amaryllifolius and Curcuma longa as photo-absorber candidates

The application of natural plant-derived dyes to replace ruthenium-based material as photo-absorber in solar cells application, have been extensively studied. Several advantages such as low cost, abundant in supply, sustainability and environmentally-safe make natural materials as current favourite photo-absorber. Natural plant-derived dyes are known containing natural compounds (e.g. carotenoids, chlorophylls, anthocyanins) that have the characteristics of electronic delocalization in extended ?-orbital system involving in electronic transfer mechanism. To date, massive investigations were done to exploit this system to be used as a potential photo-absorber in solar cells. Due to this matter, the hybrid dyes from the mixture of Pandanus amaryllifolius (pandan, P) and Curcuma longa (turmeric, T) were successfully prepared and several physical characterizations were carried out to analyse the photo-absorber (sensitizer) properties. From the results obtained, the ratios of P:T was varied into 1:2, 1:4, 4:1, and 8:1. This ratio has changed the wavelength of absorbers that were slightly shifted and the indirect bandgap (Eg) also were significantly changed. With this new approach, the bandgap of the hybrid dyes as core point in modulating electrical conductivity of photo-absorber can be simply tuned. By implying two different extract dyes to form hybrid dyes, the bandgap was found decreased with higher ratio of T used. Overall results suggesting that by adjusting the ratio of hybrid dyes, the photo-absorber properties and the Eg values were differed and with slightly modification, better electrical conductivity can be expected for solar cells application.

Water quality index and hydrogeochemistry of Otukpo area, Benue State, North Central Nigeria

The research is aimed to assess the surface and groundwater quality in Otukpo area and environs, Benue State, North Eastern Nigeria. Sixteen water samples were collected from 7 boreholes, 7 hand duck wells and 2 rivers. The water samples were analysed chemically and bacteriologically using spectrophotometric, titrimetric and membrane filtration methods. Analytical results indicated that the groundwater in the area is acidic, fresh and moderately hard. The order of abundance of the cations were in Na+<K+<Mg2+<Ca2+ while the anions were in the order of Cl-<HCO3->SO42-<NO3-. Principal Component Analysis (PCA) identified four factors that accounts for 69.73% of the total variance. Correlation analysis, Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) revealed pollution from application of agricultural fertilizers, anthropogenic contamination and rock-water interaction as the major processes responsible for the modification of surface and groundwater chemistry of the research area. The Gibbs diagram plot shows that, the sample points fall under rock dominance and weathering zones, which suggested precipitation, induced chemical weathering with the dissolution of rock-forming minerals. The piper diagram classified groundwater samples as Ca-Mg-HCO3 water type. Water Quality Index (WQI) values range from 22.05 to 56.13 which indicated good and excellent water category. The SAR values range from 0.02 to 0.66 the values belong to the excellent category and is suitable for irrigation. The overall result revealed that, the water in the research area is suitable for domestic, industrial and irrigation activities.

Facile preparation of graphene oxide silver aerogel for antibacterial

We report a simple and straightforward method for the preparation of graphene oxide-silver aerogel (GOAg) via microwave irradiation. Graphene oxide (GO) was used as a substrate for the growth of silver nanoparticles (AgNPs) and silver complex was used as a precursor. The GOAg were prepared by rapidly expose mixture of GO and silver complexes with microwave for 30 s under an ambient atmosphere. For the nanocomposites, GOAg solution were lyophilized in a freeze-dryer for 24 hours to form an aerogel. The obtained GO and GOAg nanocomposites were characterized by X-ray diffractometer (XRD) and Ultraviolet-visible spectroscopy (UV-Vis). XRD confirmed the formation GO, and GOAg while GOAg display antibacterial properties against Methicillin-resistant Staphylococcus aureus (MRSA) and Aeromonas hydrophila bacteria. We demonstrate

Effect of bleaching using sodium hydroxide on pulp derived from Sesbania grandiflora

World demand for paper is increasing. Short rotation pulpwood is needed. Sesbania grandiflora also known as Turi, is a fast growing and straight log species. The scholarly information of Turi as pulpwood are still limited. This paper aims to provide information of sodium hydroxide effect on the paper made from pulp derived from Turi. Sodium hydroxide is a common chemical using as part of full stage chemical bleaching in pulp industrial. Kraft pulp that produced using Turi, was bleached with sodium hydroxide at 3%, 6% and 9% based on pulp weight, respectively. Unbleached pulp was served as blank test. The optical and mechanical properties of handsheet paper made from bleached kraft pulp were evaluated according to TAPPI standard. The brightness and opacity of handsheet made from bleached pulp were improved with increasing the concentration of sodium hydroxide. The mechanical properties of handsheet were improved with using 3% sodium hydroxide and gradually decreased after 3% sodium hydroxide. In conclusion, sodium hydroxide is potential to improve optical properties of Turi pulp and improve the mechanical properties of paper made from Turi pulp at certain level. Excessive usage of sodium hydroxide brings adverse effect to mechanical properties of paper made from Turi pulp.

Biodiversity of benthic macroinvertebrates in Sungai Kisap, Langkawi, Kedah, Malaysia

A study on macroinvertebrate diversity was conducted in Sungai Kisap, Langkawi, Kedah. Five stations were selected with a distance of approximately 500 metres apart with three replications of benthos and two replications of water sample. The results classified Sungai Kisap in Class I, which indicates very good water quality based on WQI recommended by the Department of Environment. A total of 2 phyla, 3 classes, 8 orders, 29 families, and 3564 individuals were successfully sampled and recorded. The presence of Hydropsychidae, Baetidae, and Chironomidae with a high abundance of the families show the potential to be used as biological indicators of a clean ecosystem. The analysis showed that the average value of Shannon Diversity Index, H’ (1.28), Pielou Evenness Index, J’ (0.45), and Margaleff Richness Index, DMG (2.80) indicates that Sungai Kisap is in moderate condition and the distribution of macroinvertebrates is uniform between stations. The correlation test showed that the WQI has a strong relationship with the diversity indices involved. BMWP, ASPT, and FBI showed that Sungai Kisap has good water quality.