Pyrolysis Investigation For Bio-Oil Production From Various Biomass Feedstocks In Thailand

This study investigated the bio-oil production from vacuum pyrolysis of potential biomass feedstocks in Thailand. Experiments were carried out on palm empty fruit bunch, rice straw, rice husk, eucalyptus wood, rubber wood (Hevea Brasiliensis), and Teng wood (Shorea Obtuse) in a lab-scale-fixed bed reactor. The results showed that the product distribution was strongly dependent on temperature and biomass properties. Maximum oil yields, i.e., 50–60 wt %, were reached at 450–550°C. Due to mild temperature, most of alkalis originally present in biomass concentrated in product char, and only traces were detected in oil. Two-third of energy in biomass was in the product oil.     

Synthesis of mesoporous magnesium oxide: Its application to CO2 chemisorption

Mesoporous magnesium oxide (MgO) was synthesized using mesoporous carbon CMK-3 obtained from mesoporous SBA-15 as exotemplate. P123 was used as the structure-directing template and rice husk ash (RHA) as the silica source for the synthesis of SBA-15, which was subsequently treated with sucrose and sulphuric acid to obtain mesoporous carbon (CMK-3). X-ray powder diffraction (XRD) results and the type-IV adsorption isotherm with H1 hysteresis obtained by N₂ adsorption/desorption study for SBA-15, CMK-3 and mesoporous MgO suggests its resemblance with materials synthesized using conventional silica sources. Mesoporous MgO was subjected for CO₂ adsorption study in TGA; adsorption was 8 and 10 wt% at 25 and 100 °C, respectively. Finally, mesoporous MgO is selective to CO₂ gas, thermally stable and regenerable. Thus, this study contributes a better route to enhance CO₂ gas adsorption and use ecological waste rice husk for the synthesis of such efficient mesoporous materials.     

Evaluation of recycling efforts of aircraft companies in Wichita

The number of manufactured aircraft has been continuously increasing worldwide because of the high demand for airline transportation. During manufacturing, many advanced materials and devices are used to build various sizes and shapes of aircraft. However, most of these materials and devices require considerable energy and labor to produce, so reusing these at any life stage of the aircraft offers many economic and environmental benefits, and is considered lucrative and environmentally responsible. Several recyclable materials—composites, metals and alloys, wires, wood, paper, plastics, electronics, and avionics—emerge as waste streams during the manufacturing of aircraft. Many aircraft companies have been recycling these materials to remanufacture aircraft parts or other products for more sustainable production. In the present study, we evaluated the recycling efforts of local aircraft companies in Wichita, KS. These efforts were considered in terms of recycling efficiency/rate and environmental benefits. These included cradle-to-gate (CTG) life-cycle inventory analysis of the materials, carbon dioxide emissions, virgin material replacement with recycled materials, and natural resources usage. Our findings show that there exists a significant potential for contributions to sustainability as well as environmental and health benefits in the region from recycling by aircraft manufacturing plants.     

Bioremediation of Soil Degraded by Sewage Sludge: Effects on Soil Properties and Erosion Losses

Soils in the Mediterranean area are very prone to erosion due to the loss of organic matter and the consequent lack of protective vegetation. In this experiment a Mediterranean degraded soil with a 15% slope was amended at a rate of 250 t ha^–1 wet weight with sewage sludge and with a mixture of sewage sludge and barley straw (70% carbon from sewage sludge and 30% from the straw) in order to study their influence on soil structure recovery and hence the soilss resistance to erosion processes. Both types of organic amendment led to an improvement in several soil properties (physical, biological, and microbiological) as a result of the spontaneous growth plant covering that became evident three months after amendment. This vegetation remained throughout the two years of the experiment and prevented the water erosion processes that normally precede soil degradation. Amendment by sewage sludge alone reduced soil loss by 80% compared with the control soil, while the mixture that included both sewage sludge and barley straw reduced losses by 84%, both reducing runoff by 57%. The amended soils showed increases in the percentage of stable aggregates, the levels of the total and water-soluble C fractions, microbial biomass C, basal respiration, and the activity of the different enzymes involved in the biogeochemical cycles of C, N, and P. The results confirm the usefulness of sewage sludge as an organic amendment for recovering damaged soils.     

电子废弃物聚丙烯制备木塑复合材的研究

探讨了电子废弃物聚丙烯(PP)制备木塑复合材料(WPC)的可行性及其主要影响因子。研究结果表明:电子废弃物PP具备制备木塑复合材料的可行性,PP和木纤维混合比例是影响WPC性能的关键因子之一,加入适量的PPg-MAH有利于提高WPC的力学性能,并大幅度降低其吸水性,当PP与木纤维比例为60∶40,PP-g-MAH使用量为10%时,WPC可获得较好的综合性能指标。     

Recycling of gneiss rock waste in the manufacture of vitrified floor tiles

The present study focuses on the recycling of gneiss rock waste generated by the ornamental rock industry for manufacturing vitrified floor tile products. The gneiss rock waste came from a rock-cutting plant located in Santo Antônio de Pádua-RJ, Brazil. Initially the waste sample was characterized for chemical composition, X-ray diffraction, particle size, morphology, and pollution potential. Floor tiles containing up to 47.5 wt.% waste were prepared. The tiles were tested to determine their physical-mechanical properties (linear shrinkage, water absorption, apparent density, and flexural strength). Microstructural evolution was carried out by scanning electron microscopy. The results indicate that the gneiss rock waste could be used for vitrified floor tile production, resulting in a new possibility for recycling this waste and conserving natural resources.     

Assessing energy efficiencies and greenhouse gas emissions under bioethanol-oriented paddy rice production in northern Japan

To establish energetically and environmentally viable paddy rice-based bioethanol production systems in northern Japan, it is important to implement appropriately selected agronomic practice options during the rice cultivation step. In this context, effects of rice variety (conventional vs. high-yielding) and rice straw management (return to vs. removal from the paddy field) on energy inputs from fuels and consumption of materials, greenhouse gas emissions (fuel and material consumption-derived CO(2) emissions as well as paddy soil CH(4) and N(2)O emissions) and ethanol yields were assessed. The estimated ethanol yield from the high-yielding rice variety, "Kita-aoba" was 2.94 kL ha(-1), a 32% increase from the conventional rice variety, "Kirara 397". Under conventional rice production in northern Japan (conventional rice variety and straw returned to the paddy), raising seedlings, mechanical field operations, transportation of harvested unhulled brown rice and consumption of materials (seeds, fertilizers, biocides and agricultural machinery) amounted to 28.5 GJ ha(-1) in energy inputs. The total energy input was increased by 14% by using the high-yielding variety and straw removal, owing to increased requirements for fuels in harvesting and transporting harvested rice as well as in collecting, loading and transporting rice straw. In terms of energy efficiency, the variation among rice variety and straw management scenarios regarding rice varieties and rice straw management was small (28.5-32.6 GJ ha(-1) or 10.1-14.0 MJ L(-1)). Meanwhile, CO(2)-equivalent greenhouse gas emissions varied considerably from scenario to scenario, as straw management had significant impacts on CH(4) emissions from paddy soils. When rice straw was incorporated into the soil, total CO(2)-equivalent greenhouse gas emissions for "Kirara 397" and "Kita-aoba" were 25.5 and 28.2 Mg CO(2) ha(-1), respectively; however, these emissions were reduced notably for the two varieties when rice straw was removed from the paddy fields in an effort to mitigate CH(4) emissions. Thus, rice straw removal avers itself a key practice with respect to lessening the impacts of greenhouse gas emissions in paddy rice-based ethanol production systems in northern Japan. More crucially, the rice straw removed is available for ethanol production and generation of heat energy with a biomass boiler, all elements required for biomass-to-ethanol transformation steps including saccharification, fermentation and distillation. This indicates opportunities for further improvement in energy efficiency and reductions in greenhouse gas emissions under whole rice plant-based bioethanol production systems.     

Influence of pyrolysis temperature on production and nutrient properties of wastewater sludge biochar

The important challenge for effective management of wastewater sludge materials in an environmentally and economically acceptable way can be addressed through pyrolytic conversion of the sludge to biochar and agricultural applications of the biochar. The aim of this work is to investigate the influence of pyrolysis temperature on production of wastewater sludge biochar and evaluate the properties required for agronomic applications. Wastewater sludge collected from an urban wastewater treatment plant was pyrolysed in a laboratory scale reactor. It was found that by increasing the pyrolysis temperature (over the range from 300 °C to 700 °C) the yield of biochar decreased. Biochar produced at low temperature was acidic whereas at high temperature it was alkaline in nature. The concentration of nitrogen was found to decrease while micronutrients increased with increasing temperature. Concentrations of trace metals present in wastewater sludge varied with temperature and were found to primarily enriched in the biochar.     

Arsenic uptake and phytotoxicity of T-aman rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) grown in the As-amended soil of Bangladesh

A pot-culture experiment was conducted in open-field conditions with highly cultivated locally transplanted (T) aman rice (Oryza sativa L.) named BR-22 in arsenic (As)-amended soil (0, 1.0, 5.0, 10.0, 20.0, 30.0, 40.0 and 50.0 mg kg⁻¹ As) of Bangladesh to see the effect of As on the growth, yield and metal uptake of rice. Arsenic was applied to soil in the form of sodium arsenate (Na₂HAsO₄). Arsenic affected the plant height, tiller and panicle numbers, grain and straw yield of T-aman rice significantly (P ≤ 0.05). The grain As uptake of T-aman rice was found to increase with increase of As in soil and a high grain As uptake was observed in the treatments of 30–50 mg kg⁻¹ As-containing soil. These levels exceed the food hygiene concentration limit of 1.0 mg kg⁻¹ As. However, the straw As uptake varied significantly (P ≤ 0.05) from a low concentration of As in soil (5 mg kg⁻¹) and the highest uptake was noticed in 20 mg kg⁻¹ As treatment.     

Mechanical performance of woodfibre–waste plastic composite materials

Plastic products used for packaging are often discarded after a single use resulting in an inexhaustible supply of waste polymeric materials. The stiffness and strength of polymeric materials have been known to improve with the addition of lignocellulosic fibres available in abundance in nature. Hence, composite materials containing natural fibres and waste plastics would result in the reduction of solid wastes and the use of cheap, renewable resources. Composite specimens, consisting of waste plastics obtained from a Kerbside collection (high density polyethylene (HDPE) waste, Janitorial waste, Kerbside waste I and Kerbside waste II) and Pinus radiata woodfibres (medium density fibres (MDF)), have been produced through melt blending and injection moulding. The effects of fibre content, matrix type and interfacial bonding on the tensile and flexural properties of these composite materials have been determined through extensive testing at various conditions. The mechanical properties of these composites at room temperature and humidity depend on the amount of woodfibres, the mechanical properties of the waste plastics used and the presence of a suitable coupling agent. The tensile strengths of MDF/waste plastic composites do not generally change with fibre content except for 40% MDF/HDPE waste and 40% MDF/Kerbside waste II (plus 1% Epolene™) composites, where the tensile strengths increase by about 25% compared to those of the corresponding waste plastics. Flexural strengths of MDF/waste plastic composites increase with the addition of medium density fibres with the exception of MDF/Kerbside waste I composites. The tensile and flexural moduli of MDF/waste plastic composites mostly increase with increasing fibre content.     

Polystyrene/wood composites and hydrophobic wood coatings from water-based hydrophilic-hydrophobic block copolymers

The combination of synthetic thermoplastic polymers and wood is normally problematic because wood surfaces are hydrophilic while typical thermoplastic polymers are hydrophobic. A possible solution is to use block copolymer coupling agents. In this work we show the use of a potentially useful synthetic method of producing hydrophilic-hydrophobic block copolymers as hydrophobic coatings and coupling agents in polystyrene/wood flour composites. In particular, wood veneers are coated with water-based emulsions of hydrophilic-hydrophobic block copolymers from styrene and methacrylic acid. Dried coated surfaces are shown to become hydrophobic through dynamic contact angle measurements. When wood flour is coated with the hydrophilic-hydrophobic block copolymer based on styrene and acrylic acid, significant improvement in the ultimate tensile properties of composites formed from coated wood flour/polystyrene mixtures is realized. Since no volatile organic compounds (VOCs) are used in coating wood surfaces and subsequent composite production, improvement in mechanical properties of thermoplastic/wood flour composites are shown to occur in environmentally responsible formulations.     

环境友好新型聚乳酸复合材料的研究及应用

聚乳酸(PLA)复合材料是一类重要的环境友好新型可降解材料。该材料通常是以PLA高分子为基体,以无机钙质成分(如羟基磷灰石、磷酸钙、珊瑚、珍珠层)、碳纤维、生物活性成分、有机物等为增强材料复合而成。概述了近年来国内外通过共聚、共混、复合等改性方法获得PLA复合材料的研究进展;论述了PLA复合材料的制备方法、生物相容性、力学性能、开发现状及应用等;指出使用新型的复合工艺、采用超细的无机粒子或纳米增强材料或加入特殊填料,同时开发新型增强物质是PLA复合材料的发展趋势;展望了PLA复合材料的应用前景。     

Technological behaviour and recycling potential of spent foundry sands in clay bricks

The feasibility of recycling spent foundry sand in clay bricks was assessed in laboratory, pilot line and industrial trials, using naturally occurring sand as a reference. Raw materials were analyzed by X-ray fluorescence, X-ray diffraction, particle size distribution, and leaching and combined to produce bodies containing up to 35% wt. sand. The extrusion, drying and firing behaviour (plasticity, drying sensitivity, mechanical strength, bulk density, water absorption, and shrinkage) were determined. The microstructure, phase composition, durability and leaching (EN 12457, granular materials, end-life step, European Waste Landfill Directive; NEN 7345, monolithic materials, use-life step, Dutch Building Material Decree) were evaluated for bricks manufactured at optimal firing temperature. These results demonstrate that spent foundry sand can be recycled in clay bricks. There are no relevant technological drawbacks, but the feasibility strongly depends on the properties of the raw materials. Spent foundry sand may be introduced into bricks up to 30% wt. Most of the hazardous elements from the spent foundry sand are inertized during firing and the concentrations of hazardous components in the leachates are below the standard threshold for inert waste category landfill excepting for chromium and lead; however, their environmental risk during their use-life step can be considered negligible.     

Life cycle analysis of silane recycling in amorphous silicon-based solar photovoltaic manufacturing

Amorphous silicon (a-Si:H)-based solar cells have the lowest ecological impact of photovoltaic (PV) materials. In order to continue to improve the environmental performance of PV manufacturing using proposed industrial symbiosis techniques, this paper performs a life cycle analysis (LCA) on both conventional 1-GW scaled a-Si:H-based single junction and a-Si:H/microcrystalline-Si:H tandem cell solar PV manufacturing plants and such plants coupled to silane recycling plants. Both the energy consumed and greenhouse gas emissions are tracked in the LCA, then silane gas is reused in the manufacturing process rather than standard waste combustion. Using a recycling process that results in a silane loss of only 17% instead of conventional processing that loses 85% silane, results in an energy savings of 81,700 GJ and prevents 4400 tons of CO₂ from being released into the atmosphere per year for the single junction plant. Due to the increased use of silane for the relatively thick microcrystalline-Si:H layers in the tandem junction plants, the savings are even more substantial – 290,000 GJ of energy savings and 15.6 million kg of CO₂ eq. emission reductions per year. This recycling process reduces the cost of raw silane by 68%, or approximately $22.6 million per year for a 1-GW a-Si:H-based PV production facility and over $79 million per year for tandem manufacturing. The results are discussed and conclusions are drawn about the technical feasibility and environmental benefits of silane recycling in an eco-industrial park centered around a-Si:H-based PV manufacturing plants.     

Waste high impact polystyrene (HIPS) microfiltration membranes for water treatment: A thorough experimental study

In our previous work, the prepared high-impact polystyrene (HIPS) membranes, synthesized using four concentrations (20, 25, 30, and 35 wt%) of waste HIPS, were proved to be promising for water purification by microfiltration process (MF). However, the fabricated membranes' mechanical properties and microfiltration process parameters were not investigated. Consequently, in this study, various parameters affecting the previously fabricated membranes' performance in the filtration process, such as membrane mechanical properties, feeding pressure, fouling behavior, and polymer concentration, were thoroughly investigated. With increasing polystyrene concentrations, the ultimate tensile strength of the fabricated membranes increased. When the concentration was increased from 20 to 25 wt percent, the elongation at break rose, but as the concentration was increased further, the membrane became brittle. Permeate flux and rejection both declined as polymer content was raised. Accordingly, the highest flux and humic acid (HA) rejection were shown by 20 wt% (14.18 L/m²h (LMH) and 98.95%, respectively). The antifouling properties declined when the polymer concentration was raised, and 20 wt% had the lowest total fouling resistance. Furthermore, the permeate flux was reduced while increasing the HA initial concentration.     

Artificial aggregate made from waste stone sludge and waste silt

In this research, waste stone sludge obtained from slab stone processing and waste silt from aggregate washing plants were recycled to manufacture artificial aggregate. Fine-powdered stone sludge was mixed with waste silt of larger particle size; vibratory compaction was applied for good water permeability, resulting in a smaller amount of solidifying agent being used. For the densified packing used in this study, the mix proportion of waste stone sludge to waste silt was 35:50, which produced artificial aggregate of more compact structure with water absorption rate below 0.1%. In addition, applying vibratory compaction of 33.3 Hz to the artificial aggregate and curing for 28 days doubled the compressive strength to above 29.4 MPa. Hence, recycling of waste stone sludge and waste silt for the production of artificial aggregate not only offers a feasible substitute for sand and stone, but also an ecological alternative to waste management of sludge and silt.     

Highly siliceous MCM-48 from rice husk ash for CO2 adsorption

Mesoporous MCM-48 silica was synthesized using a cationic-neutral surfactant mixture as the structure-directing template and rice husk ash (RHA) as the silica source. The MCM-48 samples were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), N₂ physisorption and SEM. X-ray diffraction pattern of the resulting MCM-48 revealed typical pattern of cubic Ia3d mesophase. BET results showed the MCM-48 to have a surface area of 1024 m²/g and FT-IR revealed a silanol functional group at about 3460 cm⁻¹. Breakthrough experiments in the presence of MCM-48 were also carried out to test the material's CO₂ adsorption capacity. The breakthrough time for CO₂ was found to decrease as the temperature increased from 298 K to 348 K. The steep slopes observed shows the CO₂ adsorption occurred very quickly, with only a minimal mass transfer effect and very fast kinetics. In addition, amine grafted MCM-48, APTS-MCM-48 (RHA), was prepared with the 3-aminopropyltriethoxysilane (APTS) to investigate the effect of amine functional group in CO₂ separation. An order of magnitude higher CO₂ adsorption capacity was obtained in the presence of APTS-MCM-48 (RHA) compared to that with MCM-48 (RHA). These results suggest that MCM-48 synthesized from rice husk ash could be usefully applied for CO₂ removal.     

The implementation of wood waste ash as a partial cement replacement material in the production of structural grade concrete and mortar: An overview

The timber manufacturing and power generation industry is gradually shifting towards the use of biomass such as timber processing waste for fuel and energy production and to help supplement the electrical energy demand of national electric gridlines. Though timber processing waste is a sustainable and renewable source of fuel for energy production, the thermal process of converting the aforementioned biomass into heat energy produces significant amounts of fine wood waste ash as a by-product material which, if not managed properly, may result in serious environmental and health problems. Several current researches had been carried out to incorporate wood waste ash as a cement replacement material in the production of greener concrete material and also as a sustainable means of disposal for wood waste ash. Results of the researches have indicated that wood waste ash can be effectively used as a cement replacement material for the production of structural grade concrete of acceptable strength and durability performances. This paper presents an overview of the work carried out by the use of wood waste ash as a partial replacement of cement in mortar and concrete mixes. Several aspects such as the physical and chemical properties of wood waste ash, properties of wood waste ash/OPC blended cement pastes, rheological, mechanical and the durability properties of wood waste ash/OPC concrete mix are detailed in this paper.     

Co-composting of acid waste bentonites and their effects on soil properties and crop biomass

Acid waste bentonite is a byproduct from vegetable oil bleaching that is acidic (pH < 3.0) and hydrophobic. These materials are currently disposed of in landfills and could potentially have a negative impact on the effective function of microbes that are intolerant of acidic conditions. A study was undertaken using three different sources of acid waste bentonites, namely soybean oil bentonite (SB), palm oil bentonite (PB), and rice bran oil bentonite (RB). These materials were co-composted with rice husk, rice husk ash, and chicken litter to eliminate their acid reactivity and hydrophobic nature. The organic carbon (OC) content, pH, exchangeable cations, and cation exchange capacity (CEC) of the acid-activated bentonites increased significantly after the co-composting phase. In addition, the hydrophobic nature of these materials as measured using the water drop penetration time (WDPT) decreased from >10 800 s to 16 to 80 s after composting. Furthermore, these composted materials showed positive impacts on soil physical attributes including specific surface area, bulk density, and available water content for crop growth. Highly significant increases in maize biomass (Zea mays L.) production over two consecutive cropping cycles was observed in treatments receiving co-composted bentonite. The study clearly demonstrates the potential for converting an environmentally hazardous material into a high-quality soil conditioner using readily available agricultural byproducts. It is envisaged that the application of these composted acid waste bentonites to degraded soils will increase productivity and on-farm income, thus contributing toward food security and poverty alleviation.     

Durability of conventional concretes containing black rice husk ash

In this study, black rice husk ash (BRHA) from a rice mill in Thailand was ground and used as a partial cement replacement. The durability of conventional concretes with high water–binder ratios was investigated including drying shrinkage, autogenous shrinkage, depth of carbonation, and weight loss of concretes exposed to hydrochloric (HCl) and sulfuric (H₂SO₄) acid attacks. Two different replacement percentages of cement by BRHA, 20% and 40%, and three different water–binder ratios (0.6, 0.7 and 0.8) were used. The ratios of paste volume to void content of the compacted aggregate (γ) were 1.2, 1.4, and 1.6. As a result, when increasing the percentage replacement of BRHA, the drying shrinkage and depth of carbonation reaction of concretes increased. However, the BRHA provides a positive effect on the autogenous shrinkage and weight loss of concretes exposed to hydrochloric and sulfuric acid attacks. In addition, the resistance to acid attack was directly varied with the (SiO₂ + Al₂O₃ + Fe₂O₃)/CaO ratio. Results show that ground BRHA can be applied as a pozzolanic material and also improve the durability of concrete.