Preformed Amide-containing biopolymer for Improving the Environmental Performance of Synthesized Urea–formaldehyde in Agro-fiber Composites

Investigations have continued for production high performance agro-based composites using environmentally acceptable approaches. This study examines the role of adding amide-containing biopolymers during synthesis of urea–formaldehyde (UF) on properties of adhesive produced, especially its adhesion potential. The environmental performance of UF-resin synthesized in the presence of modified amide-containing biopolymer was evaluated by evaluating the free-HCHO of both adhesive (during processing) and of the eventual engineered composite product. Also, the benefits of this synthesis-modified adhesive in enhancing the bondability of sugar-cane fibers used in engineered composite panels was evaluated and compared to using UF-resin. The results obtained show that, static bending of the produced composites varied from 27.7 to 33.13 N/mm² of modulus of rupture (MOR) and from 2860 to 3374 N/mm² of Modulus of Elasticity (MOE); while for internal bond (IB) it’s varied from 0.64 to 0.866 N/mm². Based on the ANSI and EN Standards modified UF-based agro composites produced meet the performance requirements for high grade particleboards with respect to static bending strength. These agro-based composite also tested out as having free-HCHO values of ~13 mg/100 g board.     

Hybrid Composites Made from Oil Palm Empty Fruit Bunches/Jute Fibres: Water Absorption,Thickness Swelling and Density Behaviours

In this research, hybrid composite materials were prepared from combination of oil palm Empty fruit bunches (EFB) fibre and jute fibre as reinforcement, epoxy as polymer matrix. This study intended to investigate the effect of jute fiber hybridization and different layering pattern on the physical properties of oil palm EFB-Epoxy composites. Water absorption and thickness swelling test reveal that hybrid composite shows a moderate water absorption which is 11.20% for hybrid EFB/Jute/EFB composite and 6.08% for hybrid Jute/EFB/Jute composite. The thickness swelling and water absorption of the hybrid composites slightly increased as the layering pattern of hybrid composites changed. Hybrid composites are more water resistance and dimensional stable compare to the pure EFB composites. This is attributed to the more hydrophilic nature of EFB composites. Hybridization of oil palm EFB composites with jute fibres can improve the dimensional stability and density of pure EFB and Jute fibre reinforced composites has higher density of 1.2 g/cm³ compared to all other composites.     

Evaluation of photolysis and hydrolysis of pyraclostrobin in aqueous solutions and its degradation products in paddy water

This study evaluated the hydrolysis and photolysis kinetics of pyraclostrobin in an aqueous solution using ultra-high-performance liquid chromatography–photodiode array detection and identified the resulting metabolites of pyraclostrobin by hydrolysis and photolysis in paddy water using high-resolution mass spectrometry coupled with liquid chromatography. The effect of solution pH, metal ions and surfactants on the hydrolysis of pyraclostrobin was explored. The hydrolysis half-lives of pyraclostrobin were 23.1–115.5?days and were stable in buffer solution at pH 5.0. The degradation rate of pyraclostrobin in an aqueous solution under sunlight was slower than that under UV photolysis reaction. The half-lives of pyraclostrobin in a buffer solution at pH 5.0, 7.0, 9.0 and in paddy water were less than 12?h under the two light irradiation types. The metabolites of the two processes were identified and compared to further understand the mechanisms underlying hydrolysis and photolysis of pyraclostrobin in natural water. The extracted ions obtained from paddy water were automatically annotated by Compound Discoverer software with manual confirmation of their fragments. Two metabolites were detected and identified in the pyraclostrobin hydrolysis, whereas three metabolites were detected and identified in the photolysis in paddy water.     

Synthesis of functionalized mesoporous material from rice husk ash and its application in the removal of the polycyclic aromatic hydrocarbons

Environmental Science and Pollution Research - The rice husk ash (RHA) was used as an alternative source of silica for the synthesis of the functionalized mesoporous material, which was used in the...     

Towards an assessment of the influence of climate on wet acidic deposition in Europe

The EMEP precipitation composition network is used to examine relationships between non-marine SO4(2-), NO3-, NH4+, H+ concentrations and precipitation amount and a local zonal pressure index (an index of the atmospheric circulation). The pattern of the relationships changes across Europe with the zonal pressure gradient explaining more of the variance in ion concentrations in the west, and precipitation amount explaining relatively more of the variance in the east. There is some predictive capability for precipitation composition in the zonal pressure gradient for restricted regions in Europe; R2 values are up to 40% on a daily basis but in some seasons/months attain >60%. The zonal pressure gradient is an index which appears to include pertinent information on transport and wet removal. Preliminary analysis indicates that this approach can be useful in assessing the contributions of changing atmospheric circulation to time-trends of wet acidic deposition in an area stretching from the UK over the North Sea to Denmark. The zonal pressure gradient is known to have varied on time-scales of decades, and the simple index may be one appropriate approach to assessing future deposition patterns from future climate projections.     

Fractionation of atmospheric acid and base components within storm events by precipitation scavenging processes

Concentrations of ions in storm rainwater in Texas have been monitored for each 0.254 mm increment of precipitation. The changes in concentrations have been analyzed to investigate the role of differential rates of scavenging of particulate matter of differing particle size, and especially the major acid and base components. The empirical trend at the onset of rainfall is a chemical fractionation of acids and bases with correspondingly wide pH variations. These results are confirmed by model calculations, which show a significant preferential scavenging of calcium relative to sulfate in the first 10 mm of rainfall, resulting in fractionation of bases and acids from their atmospheric concentrations. Previous studies, using Target Transformation Factor Analysis of ion concentrations in storm precipitation and regional ambient aerosol data, statistically determined the average source for acidic secondary species and alkaline particulate matter. Two types of crustal sources were identified as western and eastern soil dust. In this study, an alternate physical explanation for these two soil dust factors is offered. As a storm progresses, the elements in the local soil dust are fractionated as a result of their differential rates of precipitation scavenging, enriching species predominantly in the fine particle size and depleting elements predominantly in the coarse particle size. This fractionation process results in a single source having different elemental ratios at the beginning and at the end of a rain event. For Austin, Dallas, and Tyler, Texas, the soil dust previously identified as being from eastern sources could, instead, be a fractionated form of the western soil source.     

Preparation and Fundamental Characterization of Cellulose Nanocrystal from Oil Palm Fronds Biomass

The objective of this work was to isolate cellulose nanocrystal (CNC) from oil palm fronds (Elaeis guineensis) and its subsequent characterization. Isolation involves sodium hydroxide/anthraquinone pulping with mechanical refining followed by total chlorine free bleaching (includes oxygen delignification, hydrogen peroxide oxidation and peracetic acid treatment) before acid hydrolysis. Bleaching significantly decreased kappa number and increased α-cellulose percentage of fibers as confirmed by Technical Association of the Pulp and Paper Industry standards. Transmission electron microscopy (TEM), X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis revealed that acid hydrolysis along with bleaching improved crystallinity index and thermal stability of the extracted nanocrystals. It was observed that CNC maintained its cellulose 1 polymorph despite hydrolysis treatment. Mean diameter as observed by TEM and average fiber aspect ratio of obtained CNC was 7.44 ± 0.17 nm and 16.53 ± 3.52, respectively making it suitable as a reinforcing material for nanocomposite.     

Characterization and quantification of solid waste generation in the Niger Delta Region of Nigeria: a case study of Ogbe-Ijoh community in Delta State

Journal of Material Cycles and Waste Management - In this study, the composition, characteristics and generation rates of solid waste (SW) in Ogbe-Ijoh community were investigated to provide...     

Performance of a small-scale solar-powered adsorption cooling system

In this study, an experimental investigation on the performance of a small-scale residential-size solar-driven adsorption (silica gel-water) cooling system that was constructed at Assiut University campus, Egypt is carried out. As Assiut area is considered as hot, arid climate, field tests for performance assessment of the system operation during the summer season are performed under different environmental operating conditions. The system consists of an evacuated tube with a reflective concentration parabolic surface solar-collector field with a total area of 36 m², a silica gel-water adsorption chiller of 8 kW nominal cooling capacity, and hot and cold water thermal storage tanks of 1.8 and 1.2 m³ in volume, respectively. The results of summer season field test show that under daily solar insolation varying from 21 to 27 MJ/m², the solar collectors employed in the system had high and almost constant thermal efficiency. The daily solar-collector efficiency during the period of system operation ranged from about 50% to 78%. The adsorption chiller performance shows that the chiller average daily coefficient of performance (COP) was 0.41 with the average cooling capacity of 4.4 kW when the cooling-water and chilled-water temperatures were about 31°C and 19°C, respectively. As the chiller cooling water is cooled by the cooling tower in the hot arid area, the cooling water is at a higher temperature than the design point of the chiller. Therefore, an experiment was carried out using the city water for cooling. The results show that an enhancement in the chiller COP by 40% and the chilling power by 17% has been achieved when the city water was 27.7°C.