Size control and catalytic activity of bio-supported palladium nanoparticles

The development of nanoparticles has greatly improved the catalytic properties of metals due to the higher surface to volume ratio of smaller particles. The production of nanoparticles is most commonly based on abiotic processes, but in the search for alternative protocols, bacterial cells have been identified as excellent scaffolds of nanoparticle nucleation, and bacteria have been successfully employed to recover and regenerate platinum group metals from industrial waste. We report on the formation of bio-supported palladium (Pd) nanoparticles on the surface of two bacterial species with distinctly different surfaces: the gram positive Staphylococcus sciuri and the gram negative Cupriavidus necator. We investigated how the type of bacterium and the amount of biomass affected the size and catalytic properties of the nanoparticles formed. By increasing the biomass:Pd ratio, we could produce bio-supported Pd nanoparticles smaller than 10nm in diameter, whereas lower biomass:Pd ratios resulted in particles ranging from few to hundreds of nm. The bio-supported Pd nanoparticle catalytic properties were investigated towards the Suzuki-Miyaura cross coupling reaction and hydrogenation reactions. Surprisingly, the smallest nanoparticles obtained at the highest biomass:Pd ratio showed no reactivity towards the test reactions. The lack of reactivity appears to be caused by thiol groups, which poison the catalyst by binding strongly to Pd. Different treatments intended to liberate particles from the biomass, such as burning or rinsing in acetone, did not re-establish their catalytic activity. Sulphur-free biomaterials should therefore be explored as more suitable scaffolds for Pd(0) nanoparticle formation.     

Exploration of biomass waste as low cost adsorbents for removal of methylene blue dye: A review

Biomass waste, which is abundantly available has been studied as low cost biosorbent for dye sequestration from waste water. The present review reports on recent development for remediation of methylene blue dye by agricultural waste and fruit peel waste material. The aim of this study was to revise latest literature in the field of dye adsorption and discuss the dye adsorption capacity of different types of adsorbents. The activated carbon prepared from several types of biomass waste material enhances the adsorption efficiency after modification. The variety of activating agents, method of activation, characterization of biosorbent material like SEM, EDAX, BET surface area and FTIR analysis has been explored in the present review. The dye adsorption factors such as effect of pH, agitation time, temperature, adsorbate and adsorbent dose were discussed. The detailed investigation on applicability of isotherm model, kinetic model and thermodynamic parameters has also been presented. The adsorption kinetics and adsorption isotherm model focus on selectivity of adsorbent. Adsorption mechanism, Influence of surface area, influence of pH_pzc and comparative study of biomass waste adsorbent with other adsorbents have been carried out. The use of biomass waste adsorbents is economically feasible, environmental healthy and found to have outstanding removal capacity of dyes.     

Non-catalytic and catalytic hydrothermal liquefaction of biomass

Both the non-catalytic and catalytic hydrothermal liquefaction of biomass have been the objective of extensive research in recent years. An impressive amount of scientific studies related to non-catalytic and catalytic hydrothermal liquefaction of biomass has been reported in the literature. The experimental conditions such as temperature, residence time, pressure, the types of biomass, and the types of catalysts have an important effect on the product distributions. The details about the experimental conditions as well as the compositions of bio-oils are important for a better understanding of the biomass liquefaction pathways in hydrothermal media. This review is intended to summarize and discuss a survey of relevant research.     

Catalytic phosphorus(V)-mediated nucleophilic substitution reactions: development of a catalytic Appel reaction

Catalytic phosphorus(V)-mediated chlorination and bromination reactions of alcohols have been developed. The new reactions constitute a catalytic version of the classical Appel halogenation reaction. In these new reactions oxalyl chloride is used as a consumable stoichiometric reagent to generate the halophosphonium salts responsible for halogenation from catalytic phosphine oxides. Thus, phosphine oxides have been transformed from stoichiometric waste products into catalysts and a new concept for catalytic phosphorus-based activation and nucleophilic substitution of alcohols has been validated. The present study has focused on a full exploration of the scope and limitations of phosphine oxide catalyzed chlorination reactions as well as the development of the analogous bromination reactions. Further mechanistic studies, including density functional theory calculations on proposed intermediates of the catalytic cycle, are consistent with a catalytic cycle involving halo- and alkoxyphosphonium salts as intermediates.     

Benign-by-design catalysts and processes for biomass conversion

The design of catalytic (nano)materials with improved characteristics and catalytic performance for biomass conversion-as opposed to conventional petrochemical processing- entails significant challenges from the point of view of the recalcitrance and complexity of biomass feedstocks as well as typical working conditions (e.g. aqueous processes) to deal with biomass. This contribution has been aimed to provide important insights into the fundamental understanding of the rational design of (nano)catalysts for biomass conversion, illustrated by a number of recent examples that can demonstrate the significant potential of catalysis for a more sustainable future.     

Challenges in the valorisation of chitinous biomass within the biorefinery concept

The sustainable production and use of biomass for food, structural material and packaging has become part of global development strategies. Efforts have increased in research and development (R&D) of greener energy, agriculture and manufacturing, aiming toward zero waste. However, waste is often unavoidable and needs to be considered as a new opportunity within the context of a biorefinery. Our focus is on the valorisation of chitinous biomass, in particular chitin and chitosan which is considered as the second most abundant biopolymer on earth after cellulose. Biomass and food waste that can serve as a rich source of chitin comes from diverse origins. Chitin can also be considered as a source of platform chemicals enabled by novel green catalysts. In our opinion, a more holistic evaluation of the chitinous biomass waste supply chains are required. The economics of scale will determine the future trends in R&D of chitin derived products.     

Derivative spectrophotometric analysis of benzophenone (as an impurity) in phenytoin

Background

Biomass and municipal solid waste offer sustainable sources of energy; for example to meet heat and electricity demand in the form of combined cooling, heat and power. Combustion of biomass has a lesser impact than solid fossil fuels (e.g. coal) upon gas pollutant emissions, whilst energy recovery from municipal solid waste is a beneficial component of an integrated, sustainable waste management programme. Concurrent combustion of these fuels using a fluidised bed combustor may be a successful method of overcoming some of the disadvantages of biomass (high fuel supply and distribution costs, combustion characteristics) and characteristics of municipal solid waste (heterogeneous content, conflict with materials recycling). It should be considered that combustion of municipal solid waste may be a financially attractive disposal route if a 'gate fee' value exists for accepting waste for combustion, which will reduce the net cost of utilising relatively more expensive biomass fuels.

Results

Emissions of nitrogen monoxide and sulphur dioxide for combustion of biomass are suppressed after substitution of biomass for municipal solid waste materials as the input fuel mixture. Interactions between these and other pollutants such as hydrogen chloride, nitrous oxide and carbon monoxide indicate complex, competing reactions occur between intermediates of these compounds to determine final resultant emissions.

Conclusions

Fluidised bed concurrent combustion is an appropriate technique to exploit biomass and municipal solid waste resources, without the use of fossil fuels. The addition of municipal solid waste to biomass combustion has the effect of reducing emissions of some gaseous pollutants.     

Catalytic Reduction of Cyclic Ethers with Hydrosilanes

Catalytic reductive transformations of ethers as a synthetic building block are an important class of chemical reactions because a range of essential chemical feedstocks and fuels in contemporary life can be prepared through the key step of ethereal C?O bond cleavage of cellulosic biomass. Although conventional stoichiometric and catalytic methods for sp²‐ and sp³‐C?O bond cleavage of linear ethers and alcohols with hydrosilanes are well established, silylative ring opening of cyclic ethers has been less highlighted in this context. This review outlines catalytic systems for the silylative reduction of a range of cyclic ethers, including epoxides and sugars, leading to the corresponding alcohols and/or hydrocarbons. The chemical reactivity and selectivity of these ring‐opening catalytic processes are discussed with respect to the type of substrates; the representative catalytic working modes are also described.     

Chemical Upcycling of Waste Plastics to High Value-Added Products via Pyrolysis: Current Trends,Future Perspectives,and Techno-Feasibility Analysis

Chemical upcycling of waste plastics into high-value-added products is one of the most effective, cost-efficient, and environmentally beneficial solutions. Many studies have been published over the past few years on the topic of recycling plastics into usable materials through a process called catalytic pyrolysis. There is a significant research gap that must be bridged in order to use catalytic pyrolysis of waste plastics to produce high-value products. This review focuses on the enhanced catalytic pyrolysis of waste plastics to produce jet fuel, diesel oil, lubricants, aromatic compounds, syngas, and other gases. Moreover, the reaction mechanism, a brief and critical comparison of different catalytic pyrolysis studies, as well as the techno-feasibility analysis of waste plastic pyrolysis and the proposed catalytic plastic pyrolysis setup for commercialization is also covered.     

Dye and its removal from aqueous solution by adsorption: A review

In this review article the authors presented up to-date development on the application of adsorption in the removal of dyes from aqueous solution. This review article provides extensive literature information about dyes, its classification and toxicity, various treatment methods, and dye adsorption characteristics by various adsorbents. One of the objectives of this review article is to organise the scattered available information on various aspects on a wide range of potentially effective adsorbents in the removal of dyes. Therefore, an extensive list of various adsorbents such as natural materials, waste materials from industry, agricultural by-products, and biomass based activated carbon in the removal of various dyes has been compiled here. Dye bearing waste treatment by adsorption using low cost alternative adsorbent is a demanding area as it has double benefits i.e. water treatment and waste management. Further, activated carbon from biomass has the advantage of offering an effected low cost replacement for non-renewable coal based granular activated carbon provided that they have similar or better adsorption on efficiency. The effectiveness of various adsorbents under different physico-chemical process parameters and their comparative adsorption capacity towards dye adsorption has also been presented. This review paper also includes the affective adsorption factors of dye such as solution pH, initial dye concentration, adsorbent dosage, and temperature. The applicability of various adsorption kinetic models and isotherm models for dye removal by wide range of adsorbents is also reported here. Conclusions have been drawn from the literature reviewed and few suggestions for future research are proposed.     

Quantum Mechanical Calculations for Biomass Valorization over Metal-Organic Frameworks (MOFs)

Metal-organic framework (MOF) in biomass valorization is a promising technology developed in recent decades. By tailoring both the metal nodes and organic ligands, MOFs exhibit multiple functionalities, which not only extend their applicability in biomass conversion but also increase the complexity of material designs. To address this issue, quantum mechanical simulations have been used to provide mechanistic insights into the catalysis of biomass-derived molecules, which could potentially facilitate the development of novel MOF-based materials for biomass valorization. The aim of this review is to survey recent quantum mechanical simulations on biomass reactions occurring in MOF catalysts, with the emphasis on the studies of the catalytic activity of active sites and the effects of organic ligand and porous structures on the kinetics. Moreover, different model systems and computational methods used for MOF simulations are also surveyed and discussed in this review.     

废弃天然高分子基功能材料

从废弃高分子角度对废弃生物质的高附加值再利用进行综述,阐述了废弃生物质中天然高分子的类型以及废弃生物质中包含的大量天然高分子具有官能团丰富、可降解、生物相容、无毒无害等优异的性能,归纳了废弃生物质的传统处理方法及作为材料使用的再利用途径,介绍了废弃天然高分子用作复合材料、吸附材料、载体材料、能源材料、医用高分子材料、智能高分子材料等的研究进展,并对废弃天然高分子的资源化利用进行了展望。     

Fast pyrolysis of waste pepper stem over waste FCC catalyst

Fast pyrolysis of waste pepper stem was investigated using waste FCC catalyst and HY zeolite with a SiO₂/Al₂O₃ ratio of 5.1. The pyrolysis oil obtained from the pyrolysis at 500 °C was analyzed using GC/MS. Oxygenates were converted, in particular when the catalyst dose was high, to furans and aromatics. The contents of low-molecular-mass phenolics and aromatics increased with increasing quantity of acid sites deployed. On the other hand, the content of high-molecular-mass phenolics was increased by catalysis with the biomass:catalyst ratio of 1:1, whereas it was decreased by catalysis with the biomass:catalyst ratio of 1:10. This was explained by the pathway of lignin-to-aromatics conversion: lignin → high-molecular-mass phenolics → low-molecular-mass phenolics → aromatics. Activated waste FCC catalyst showed a little weaker catalytic activity for the conversion of low-molecular-mass phenolics to aromatics than HY, leading to a higher phenolics content and a lower aromatics content. The results of this study indicate that the catalytic pyrolysis of lignin-rich biomass over waste FCC catalyst can be a promising way of recycling waste FCC catalyst for the production of high-value-added chemicals, such as furans, phenolics and aromatics.     

催化裂化生物质焦油构成变化

利用层析法对生物质焦油进行分析,比较了不同来源、不同裂化工况处理后焦油族分构成的差异,并对催化裂化过程机理进行探讨。生物质原料组成的不同导致热解焦油构成的差异,木屑焦油中芳香类和极性物的质量分数高于稻杆和稻壳焦油,热解温度越高产生的焦油芳香性越大。催化裂化后,芳香类族分在焦油中的质量分数增长近1倍,其他族分的质量分数出现不同幅度的下降,裂化温度950℃以上时,芳香类的质量分数已达50％。芳香类的转化速度较小,还存在其他族分向芳香类的转化,引起裂化后焦油芳香化程度增大,且这种趋势随焦油转化程度的增大而更为明显。     

Butenolide Derivatives of Biobased Furans: Sustainable Synthetic Dyes

The dye and pigment manufacturing industry is one of the most polluting in the world. Each year, over one million tons of petrochemical colorants are produced globally, the synthesis of which generates a large amount of waste. Naturally occurring, plant‐based dyes, on the other hand, are resource intensive to produce (land, water, energy), and are generally less effective as colorants. Between these two extremes would be synthetic dyes that are fully sourced from biomass‐derived intermediates. The present work describes the synthesis of such compounds, containing strong chromophores that lead to bright colors in the yellow to red region of the visible spectrum. The study was originally motivated by an early report of an unidentified halomethylfurfural derivative which resulted from hydrolysis in the presence of barium carbonate, now characterized as a butenolide of 5‐(hydroxymethyl)furfural (HMF). The method has been generalized for the synthesis of dyes from other biobased platform molecules, and a mechanism is proposed.     

Evaluation of Methanogenic Activity of Biogas Plant Slurry for Monitoring Codigestion of Ossein Factory Wastes and Cyanobacterial Biomass

Overall measurement of methanogenic activity of sludge and or slurry is thought as a key for understanding the basic physiology of anaerobic consortia involved in anaerobic digestion process of an alternative biomass. In this study, the methanogenic activity of biogas plant slurry was used to evaluate the anaerobic digestion of ossein factory wastes such as sinews and primary clarified bone waste (PCBW) and cyanobacterial biomass in standard assay conditions. A maximum methanogenic activity was reported here when ossein factory wastes mixed with cyanobacterial biomass in specific proportions in which sinews and PCBW alone also favored to a significant methane yield. Cyanobacterial biomass alone did not give a desirable methanogenic activity. Approximately 48% of total solids were destroyed from these wastes after 30 days. This study gives information on the use of these wastes with suitable proportions for taking an effort in a large-scale anaerobic digestion in an effective way of ossein factory.     

Removal of biomass tar by steam reforming over calcined scallop shell supported Cu catalysts

In this study, the main purpose is to develop low-cost catalysts with high activity and stability for high quality syngas production via steam reforming of biomass tar in biomass gasification process. The calcined waste scallop shell(CS) supported copper(Cu) catalysts are prepared for steam reforming of biomass tar. The prepared Cu supported on CS catalysts exhibit higher catalytic activity than those on commercial CaO and Al_2O_3. Characterization results indicate that Cu/CS has a strong interaction between Cu and CaO in CS support, resulting in the formation of calcium copper oxide phase which could stabilize Cu species and provide new active sites for the tar reforming. In addition, the strong basicity of CS support and other inorganic elements contained in CS support could enhance the activity of Cu/CS. The addition of a small amount of Co is found to be able to stabilize the catalytic activity of Cu/CS catalysts,making them reusable after regeneration without any loss of their activities.     

Development of a novel,two-step process for treating municipal biosolids for beneficial reuse

Modern municipal sewage waste treatment plants use conventional mechanical and biological processes to reclaim wastewaters. This process has an overall effect of converting a water pollution problem into a solid waste disposal problem (sludges or biosolids). An estimated 10 million tons of biosolids, which require final disposal, are produced annually in the United States. Although numerous disposal options for biosolids are available, including land application, landfilling, and incineration, disposal costs have risen, partly because of increased federal and local environmental restrictions(1). A novel, thermomechanical biosolids pre-treatment process, which allows for a variety of potential value-added uses, was developed. This two-step process first employs thermal explosive decompression to inactivate or kill the microbial cells and viruses. This primary step also results in the rupture of a small amount of the microbial biomass and increases the intrinsic fluidity of the biosolids. The second step uses shear to effect a near-complete rupturing of the microbial biomass, and shears the nondigested organics, which increases the overall surface area. Pretreated biosolids may be subjected to a secondary anaerobic digestion process to produce additional fuel gas, and to provide for a high-quality, easily dewatered compost product. This novel biosolids pretreatment process was recently allowed a United States patent.     

分子筛上糖类催化转化的核磁共振研究

葡萄糖、 果糖和木糖等糖类是一类重要的绿色生物质资源, 其高效利用是生物质转化的重要研究方向. 具有Lewis酸性的分子筛在糖类催化转化中表现出优异的性能, 对其活性中心结构、 性质以及反应机理的认识是糖类高效转化研究中亟待解决的关键科学问题. 核磁共振是分子筛上活性中心表征和反应机理研究的重要手段. 本文讨论了先进核磁共振技术与方法在分子筛上糖类转化反应中的应用, 包括催化剂活性中心表征、 催化转化反应机理研究和催化反应产物分析3个方面, 总结了核磁共振在糖类转化反应研究中所取得的新进展并对其未来发展方向进行了展望.     

Coordinating California’s efforts to promote waste to alcohol production

Alcohol fuels produced from biomass can improve air quality, enhance energy security, create employment opportunities, and reduce waste disposal problems. Opportunities in California exist to produce alcohols from waste streams from various sectors of the economy. Government agencies have promoted waste-to-alcohol activities, but efforts have been inconsistent and intermittent. Often these efforts have been hindered by contradictory but mandate-driven policies. A prudent approach to coordinate statewide efforts includes the development of an integrated statewide policy to examine barriers that impede private sector business efforts to produce alcohols from biomass. A multi-agency task force to promote research, development, commercialization, and marketing efforts for biomass-produced alcohols is desirable. The views and opinions contained in this document do not necessarily reflect those of the California Energy Commission, its staff, management, or the State of California.