Mechanical properties of shotcrete with addition of sugarcane bagasse fiber and ash

Journal of Material Cycles and Waste Management - Shotcrete is a sprayed concrete placed on steep slopes that have been widely used because it can prevent surface weathering and erosion, and in...     

Pyrolysis of polypropylene waste using sulfonated carbon catalyst synthesized from sugarcane bagasse

Journal of Material Cycles and Waste Management - In this study, thermal and catalytic pyrolysis of polypropylene waste (PP) was investigated using a batch reactor in the temperature range...     

锅炉酸洗柠檬酸废液处理

从理论上分析了经NaOH溶液预处理的柠檬酸酸洗废液再用灰水进行处理，降低COD值的可行性，实际应用结果表明，该方案可以达到“以废治废”的目的。     

Effect of the addition of sugarcane bagasse composts on micronutrient assimilability in ryegrass

An experiment was conducted under greenhouse conditions to determine the effect of different applied sugarcane bagasse composts on micronutrient assimilability. Five treatments were prepared: soil alone (C), soil+mineral complements of N, P and K (NPK) and three treatments, containing soil+different sugarcane bagasse composts at 100 t ha⁻¹. A ryegrass culture (Lolium perenne L. c.v. Varna) was grown in pots from which five harvests of plant material were obtained. Soil samples of each treatment were collected before sowing and after the third and fifth harvests. The addition of sugarcane bagasse composts to soil increased DTPA-extractable Fe, Mn, Cu and Zn throughout the entire experiment in comparison with C and NPK. These organic materials also led to an increase in Fe, Cu and Zn uptake by plants after the second harvest.     

Comparison of composting of chemically pretreated and fermented sugarcane bagasse for zero-waste biorefinery

Journal of Material Cycles and Waste Management - Sugar industries produce vast quantity of sugarcane bagasse (SCB) waste which is used as raw material by biorefineries; however, the resulted...     

Ethanol production from banana peels using statistically optimized simultaneous saccharification and fermentation process

Dried and ground banana peel biomass (BP) after hydrothermal sterilization pretreatment was used for ethanol production using simultaneous saccharification and fermentation (SSF). Central composite design (CCD) was used to optimize concentrations of cellulase and pectinase, temperature and time for ethanol production from BP using SSF. Analysis of variance showed a high coefficient of determination (R²) value of 0.92 for ethanol production. On the basis of model graphs and numerical optimization, the validation was done in a laboratory batch fermenter with cellulase, pectinase, temperature and time of nine cellulase filter paper unit/gram cellulose (FPU/g-cellulose), 72 international units/gram pectin (IU/g-pectin), 37 °C and 15 h, respectively. The experiment using optimized parameters in batch fermenter not only resulted in higher ethanol concentration than the one predicted by the model equation, but also saved fermentation time. This study demonstrated that both hydrothermal pretreatment and SSF could be successfully carried out in a single vessel, and use of optimized process parameters helped achieve significant ethanol productivity, indicating commercial potential for the process. To the best of our knowledge, ethanol concentration and ethanol productivity of 28.2 g/l and 2.3 g/l/h, respectively from banana peels have not been reported to date.     

Biogas production from malt bagasse from craft beer industry: kinetic modeling and process simulation

Journal of Material Cycles and Waste Management - In this work, biogas was synthesized from malt enriched-craft beer bagasse with the objective to generate clean energy. Thus, a kinetic model based...     

Landfill leachate enhances fermentative hydrogen production from glucose and sugarcane processing derivatives

Fermentation can use renewable raw materials as substrate, which makes it a sustainable method to obtain H₂. This study evaluates H₂ production by a mixed culture from substrates such as glucose and derivatives from sugarcane processing (sucrose, molasses, and vinasse) combined with landfill leachate. The leachate alone was not a suitable substrate for biohydrogen production. However, leachate blended with glucose, sucrose, molasses, or vinasse increased the H₂ production rate by 2.0-, 2.8-, 4.6-, and 0.5-fold, respectively, as compared with the substrates without the leachate. Determination of metals (Cu, Cd, Pb, Hg, Ni, and Fe) at the beginning and at the end of the fermentative assays showed how they were consumed during the fermentation and demonstrated improved H₂ production. During fermentation, Cu, Fe, and Cd were the most consumed leachate metals. The best substrate combination to produce H₂ was molasses and leachate, which gave high volumetric productivity—469 ml H₂/l h. However, addition of the leachate to the substrates stimulated lactic acid formation pathways, which lowered the H₂ yield. The use of leachate combined with sugarcane processing derivatives as substrates could add value to the leachate and reduce its polluting power, generating a clean energy source from renewable raw materials.     

水催化泔水油生产甘油硬脂酸的清洁生产工艺

探讨了泔水油水解工艺,从酸析、水洗、压力、温度、水解等条件进行研究。本工艺直接用水作催化剂,适应成分复杂的餐饮泔水油,污水处理简单。采用的工艺条件是:压力,3.5 MPa;加水量,35%左右。同时需要指出的是,加水量一般是根据中性油的含量来计算,因为游离脂肪酸不需水解。     

用于火电厂循环水精滤的CKL型自动清洗滤水装置

介绍了自行研制开发的CKL型自动清洗滤水装置的机械结构、工作原理和特点。该装置是针对我国大机组火电建设中循环水精滤设备需要进口的问题，在充分了解该类产品国内外的技术水平，各种不同结构型式装置的优缺点和实际运行状况的基础上研制成功的。     

Effect of water washing on the thermal behavior of rice straw

Rice straw can be used as a renewable fuel for heat and power generation. It is a viable mean of replacing fossil fuels and preventing pollution caused by open burning, especially in the areas where this residual biomass is generated. Nevertheless, the thermal conversion of rice straw can cause some operating problems such as slag formation, which negatively affects thermal conversion systems. So, the main objective of this research is studying the combustion behavior of rice straw samples collected from various regions by applying thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). In addition, the thermal behavior of ashes from rice straw was also analyzed in order to detect their melting points, and ash sintering was detected at different temperatures within the range between 550 and 1000 °C. Since washing rice straw with water could reduce the content of undesirable inorganic compounds related to the ash fusibility, samples of washed rice straw were analyzed under combustion conditions to investigate its differences regarding the thermal behavior of rice straw. The results showed that rice straw washing led to a significant improvement in its thermal behavior, since it reduced the ash contents and sintering formation.     

表面活性剂与柠檬酸联合洗涤高黏性土壤中的重金属

以一水合柠檬酸（CA）为洗涤剂,分别采用吐温80（TW80）、十二烷基磺酸钠（SDS）、β-环糊精（BCD）和腐植酸（HA）4种表面活性剂与CA联合洗涤高黏性土壤中的重金属,考察表面活性剂与CA的联合洗脱效果。实验结果表明：添加4种表面活性剂均可提高CA对Cu、Zn和Pb的去除率;处理时无需调节体系pH;在表面活性剂与CA的混合液与土壤的液固比为10:1（mL/g）的条件下,采用一次洗涤即可。经4种表面活性剂与CA联合洗涤后,土壤中Cu、Zn和Pb的离子交换态、碳酸盐结合态和铁锰氧化结合态的占比均下降,而硫化物及有机结合态和残渣态的占比有所提升。     

氯化锌活化法制备甘蔗渣活性炭吸附剂

采用氯化锌活化法制备了甘蔗渣活性炭吸附剂,并考察了活化剂氯化锌溶液浓度、活化温度和活化时间对吸附剂吸附性能的影响。实验结果表明,氯化锌活化法制备甘蔗渣活性炭吸附剂的最佳工艺条件为：活化温度800℃、氯化锌溶液质量浓度190g／L、活化时间60min。所得甘蔗渣活性炭吸附剂的得率为30．3％,碘吸附值为1070mg／g,亚甲基蓝吸附值（以0．1g吸附剂吸附的亚甲基蓝体积计）为15．0mL,达到了GB／T13803．2—1999《木质净水用活性炭》一级品标准（碘吸附值1000mg／g,亚甲基蓝吸附值9mL）。     

Improved method for the formation of recycled resins from depolymerized products of waste fiber-reinforced plastics: simple and effective purification of recovered monomers by washing with water

The synthesis of recycled plastics from recovered monomeric materials obtained from the depolymerization reaction of fiber-reinforced plastics (FRP) was examined. The depolymerization reaction of FRP in the presence of N,N-dimethylaminopyridine (DMAP) smoothly yielded the corresponding monomers, which mainly consisted of dimethyl phthalates. The polymerization reaction with this monomer failed to form the corresponding unsaturated polyesters due to contamination by N-methyl-4-pyridone, a decomposition product of DMAP. An efficient purification of the recovered monomer was achieved by washing with water, and the purified monomer successfully yielded the corresponding polymers. A hardness test revealed that the polymers were as hard as the polyester made from virgin materials. The present modification provides a practical method for the preparation of recycled plastics from depolymerized plastics.     

Geopolymerisation of silt generated from construction and demolition waste washing plants

Recycling plants that size, sort and wash construction and demolition waste can produce high quality aggregate. However, they also produce up to 80ton per hour of filter cake waste containing fine (<63mum) silt particles that is classified as inert waste and normally landfilled. This research investigated the potential to form geopolymers containing silt, which would allow this problematic waste to be beneficially reused as aggregate. This would significantly improve the economic viability of recycling plants that wash wastes. Silt filter cakes have been collected from a number of aggregate washing plants operating in the UK. These were found to contain similar aluminosilicate crystalline phases. Geopolymer samples were produced using silt and silt mixed with either metakaolin or pulverised fuel ash (PFA). Silt geopolymers cured at room temperature had average 7-day compressive strengths of 18.7MPa, while partial substitution of silt by metakaolin or PFA increased average compressive strengths to 30.5 and 21.9MPa, respectively. Curing specimens for 24h at 105 degrees C resulted in a compressive strength of 39.7MPa and microstructural analysis confirmed the formation of dense materials. These strengths are in excess of those required for materials to be used as aggregate, particularly in unbound applications. The implications of this research for the management of waste silt at construction and demolition waste washing plants are discussed.     

Recovery of metals from waste printed circuit boards by supercritical water pre-treatment combined with acid leaching process

Waste printed circuit boards (PCBs) contain a large number of metals such as Cu, Sn, Pb, Cd, Cr, Zn, and Mn. In this work, an efficient and environmentally friendly process for metals recovery from waste PCBs by supercritical water (SCW) pre-treatment combined with acid leaching was developed. In the proposed process, waste PCBs were pre-treated by SCW, then the separated solid phase product with concentrated metals was subjected to an acid leaching process for metals recovery. The effect of SCW pre-treatment on the recovery of different metals from waste PCBs was investigated. Two methods of SCW pre-treatment were studied: supercritical water oxidation (SCWO) and supercritical water depolymerization (SCWD). Experimental results indicated that SCWO and SCWD pre-treatment had significant effect on the recovery of different metals. SCWO pre-treatment was highly efficient for enhancing the recovery of Cu and Pb, and the recovery efficiency increased significantly with increasing pre-treatment temperature. The recovery efficiency of Cu and Pb for SCWO pre-treatment at 420 °C was 99.8% and 80%, respectively, whereas most of the Sn and Cr were immobilized in the residue. The recovery of all studied metals was enhanced by SCWD pre-treatment and increased along with pre-treatment temperature. Up to 90% of Sn, Zn, Cr, Cd, and Mn could be recovered for SCWD pre-treatment at 440 °C.     

Polyalkylphenyl-sulphonic acid with acid groups of variable strength from compost

The insoluble organic fraction (humin-like material, HLM) from rice hull-dairy cattle compost is well converted into water soluble HLM-sulphonate by reaction in liquid SO3. Microanalytical, potentiometric, molecular weight, and NMR data are consistent with a highly homogeneous polymeric arylsulphonate having 4000 Da MW, 1.3 sulphonic groups per aromatic ring and significant content of carboxylic and phenolic groups. By comparison with structure-property relationships for commercial lignosulphonates derived from the pulp and paper industry, the above arylsulphonate is likely to be a candidate at a variety of applications in the chemical industry and in agriculture. Therefore, sulphonation is a means for upgrading composts HLM to the same uses as for commercial lignosulphonates.     

Heavy metal release from different ashes during serial batch tests using water and acid

Most ashes contain a significant amount of heavy metals and when released from disposed or used ash materials, they can form a major environmental concern for underground waters. The use of water extracts to assess the easily mobilisable content of heavy metals may not provide an appropriate measure. This study describes the patterns of heavy metal release from ash materials in context with results from the German standard extraction method DIN-S4 (DIN 38 414 S4). Samples of four different ashes (municipal solid waste incineration ash, wood ash, brown coal ash and hard coal ash) were subjected to a number of serial batch tests with liquid renewal, some of which involved the addition of acid to neutralize carbonates and oxides. Release of heavy metals showed different patterns depending on the element, the type of material, the method of extraction and the type of the extractant used. Only a small fraction of the total heavy metal contents occurred as water soluble salts; of special significance was the amount of Cr released from the wood ash. The reaction time (1, 24 or 72 h between each extraction step with water) had only a small effect on the release of heavy metals. However, the release of most of the heavy metals was governed by the dissolution processes following proton inputs, indicating that pH-dependent tests such as CEN TC 292 or others are required to estimate long-term effects of heavy metal releases from ashes. Based on the chemical characteristics of ash materials in terms of their form and solubility of heavy metals, recommendations were made on the disposal or use of the four ash materials.     

Thermal and enzymatic recovering of proteins from untanned leather waste

The laboratory trials of a process to treat untanned leather waste to isolate valuable protein products are presented. In this comparative study, both thermal and enzymatic treatments of leather waste were performed. The enzymatic method utilizes commercially available alkaline protease at moderate temperatures and for short periods of time. The concentration of the enzyme was 500 units per gram of leather waste which makes the method cost-effective. Amino acid composition in the hydrolysate obtained by the enzyme hydrolysis of untanned leather waste is determined. Chemical and physical properties of protein powder products from untanned leather waste were evaluated by spectrophotometric and chromatographic methods and by use of electron microscope. The results of microbiological assays confirm that these products agree to food safety standards. This relatively simple treatment of untanned leather waste may provide a practical and economical solution to the disposal of potentially dangerous waste.     

Removal of Cr6 + and Ni2+ from aqueous solution using bagasse and fly ash

Raw bagasse and fly ash, the waste generated in sugar mills and boilers respectively have been used as low-cost potential adsorbents. Raw bagasse was pretreated with 0.1N NaOH followed by 0.1N CH3COOH before its application. These low-cost adsorbents were used for the removal of chromium and nickel from an aqueous solution. The kinetics of adsorption and extent of adsorption at equilibrium are dependent on the physical and chemical characteristics of the adsorbent, adsorbate and experimental system. The effect of hydrogen ion concentration, contact time, sorbent dose, initial concentrations of adsorbate and adsorbent and particle size on the uptake of chromium and nickel were studied in batch experiments. The Sorption data has been correlated with Langmuir, Freundlich and Bhattacharya and Venkobachar adsorption models. The efficiencies of adsorbent materials for the removal of Cr(VI) and Ni(II) were found to be between 56.2 and 96.2% and 83.6 and 100%, respectively. These results were obtained at the optimized conditions of pH, contact time, sorbent dose, sorbate concentration of 100 mg/l and with the variation of adsorbent particles size between 0.075 and 4.75 mm. The order of selectivity is powdered activated carbon > bagasse > fly ash for Cr(VI) removal and powdered activated carbon > fly ash > bagasse for Ni(II) removal.