Journal of Chemical Technology and Biotechnology

Biosorption may be simply defined asthe removal of substances from solution by biological material. Such substances can be organic and inorganic, and in gaseous, soluble or insoluble forms. Biosorption is a physico‐chemical process and includes such mechanisms as absorption, adsorption, ion exchange, surface complexation and precipitation. Biosorption is a property of both living and dead organisms (and their components) and has been heralded as a promising biotechnology for pollutant removal from solution, and/or pollutant recovery, for a number of years, because of its efficiency, simplicity, analogous operation to conventional ion exchange technology, and availability of biomass. Most biosorption studies have carried out on microbial systems, chiefly bacteria, microalgae and fungi, and with toxic metals and radionuclides, including actinides like uranium and thorium. However, practically all biological material has an affinity for metal species and a considerable amount of other research exists with macroalgae (seaweeds) as well as plant and animal biomass, waste organic sludges, and many other wastes or derived bio‐products. While most biosorption research concerns metals and related substances, including radionuclides, the term is now applied to particulates and all manner of organic substances as well. However, despite continuing dramatic increases in published research on biosorption, there has been little or no exploitation in an industrial context. This article critically reviews aspects of biosorption research regarding the benefits, disadvantages, and future potential of biosorption as an industrial process, the rationale, scope and scientific value of biosorption research, and the significance of biosorption in other waste treatment processes and in the environment. Copyright © 2008 Society of Chemical Industry

This review summarizes recent applications of ionic liquids (ILs) as ‘green’ solvents in extractions of a variety of substances, including metal ions, organic and bio‐molecules, organosulfur from fuels, and gases. ILs could also be used along with another ‘green’ technology, supercritical fluid extraction (SFE), for a more effective separation of products from ILs. In addition to their environmentally‐benign feature, ILs have other favorable properties over organic solvents used for extraction, such as adjustable hydrophobicity, polarity and selectivity. Copyright © 2005 Society of Chemical Industry

Polycyclic aromatic hydrocarbons (PAHs) are a class of organic compounds that have accumulated in the natural environment mainly as a result of anthropogenic activities such as the combustion of fossil fuels. Interest has surrounded the occurrence and distribution of PAHs for many decades due to their potentially harmful effects to human health. This concern has prompted researchers to address ways to detoxify/remove these organic compounds from the natural environment. Bioremediation is one approach that has been used to remediate contaminated land and waters, and promotes the natural attenuation of the contaminants using the in situ microbial community of the site. This review discusses the variety of fungi and bacteria that are capable of these transformations, describes the major aerobic and anaerobic breakdown pathways, and highlights some of the bioremediation technologies that are currently available. Copyright © 2005 Society of Chemical Industry

Increased and accelerated global economic activities over the past century have led to interlinked problems that require urgent attention. The current patterns of production and consumption have raised serious concerns. In this context, greater emphasis has been put on the concept of sustainable economic systems that rely on technologies based on and supporting renewable sources of energy and materials. Average UK households produce around 3.2 million tonnes of packaging waste annually whereas 150 million tonnes of packaging waste is generated annually by industries in the UK. Hence, the development of biologically derived biodegradable polymers is one important element of the new economic development. Key among the biodegradable biopolymers is a class known as polyhydroxyalkanoates. Polyhydroxyalkanoates (PHAs) are a family of polyhydroxyesters of 3‐, 4‐, 5‐ and 6‐hydroxyalkanoic acids, produced by a variety of bacterial species under nutrient‐limiting conditions with excess carbon. These water‐insoluble storage polymers are biodegradable, exhibit thermoplastic properties and can be produced from renewable carbon sources. Thus, there has been considerable interest in the commercial exploitation of these biodegradable polyesters. In this review various applications of polyhydroxyalkanoates are discussed, covering areas such as medicine, agriculture, tissue engineering, nanocomposites, polymer blends and chiral synthesis. Overall this review shows that polyhydroxyalkanoates are a promising class of new emerging biopolymers. Copyright © 2007 Society of Chemical Industry

Mặc dù có một số công nghệ tách bốc hơi có khả năng về mặt kỹ thuật trong việc loại bỏ các sản phẩm dễ bay hơi từ nước lên men, chưng cất vẫn là công nghệ chiếm ưu thế. Điều này đặc biệt đúng đối với việc thu hồi nhiên liệu sinh học như ethanol. Trong bài báo này, tình trạng của công nghệ tách màng nổi lên, được gọi là công nghệ bốc hơi nước cho ứng dụng này, đã được xem xét. Nhiều vấn đề và ưu tiên nghiên cứu có thể ảnh hưởng đến khả năng cạnh tranh của công nghệ bốc hơi nước để thu hồi nhiên liệu sinh học từ các hệ thống lên men được xác định và thảo luận. Chúng bao gồm: tăng cường hiệu suất sử dụng năng lượng; giảm chi phí vốn cho các hệ thống bốc hơi nước; các thử nghiệm dài hạn với nước lên men thực tế; tối ưu hóa tích hợp công nghệ bốc hơi nước với thiết bị lên men; sự cộng hưởng khi thực hiện cả việc thu hồi rượu và khử nước dung môi bằng công nghệ bốc hơi nước với công nghệ ngưng tụ phân đoạn đông lạnh; và phân tích kinh tế cập nhật của công nghệ bốc hơi nước ở các quy mô sản xuất nhiên liệu sinh học khác nhau. Công nghệ bốc hơi nước hiện đang khả dụng để thu hồi nhiên liệu sinh học trong một số tình huống, nhưng việc ứng dụng rộng rãi hơn sẽ chỉ có thể khi có tiến bộ trong những vấn đề này. Được xuất bản vào năm 2005 cho SCI bởi John Wiley & Sons, Ltd.

The adsorption of Escherichia coli on different activated carbons has been studied. The activated carbon samples used have been characterized, determining their surface area, pore size distribution, elemental analysis, mineral matter analysis and pH of the point of zero charge. The adsorption capacity of these carbons increased with their hydrophobicity and macropore volume. The number of bacteria adsorbed on the demineralized activated carbon in a solution of pH value equal to the iso‐electric point of the carbon was negligible. However, in the presence of cations the proportions of bacterial cells adsorbed were 87.8% (Fe³⁺), 54.7% (Ca²⁺) and 24.8% (Mg²⁺) respectively. This increase in adsorption capacity in the presence of electrolytes has been explained on the basis of both the reduction in electrostatic free energy and the increase in cell surface hydrophobicity due to the metal bound by some compounds of the cell membrane. When the solution pH was intermediate between the pH values of the point of zero charge of the carbon and bacteria the number of bacteria adsorbed increased due to the attractive interactions between the carbon and bacteria. The adsorption of bacteria on activated carbons decreased the porosity and increased the negative charge density of the latter. Depending on the experimental conditions used, the presence of bacteria can enhance the capacity of activated carbons to adsorb lead.

© 2001 Society of Chemical Industry

Furfural is a natural precursor to furan‐based chemicals and has the potential to become a major renewable platform chemical for the production of biochemicals and biofuels. However, current industrial furfural production relies on relatively old and inefficient strategies that have hindered its capacity, and low production yields have strongly diminished its competitiveness with petroleum‐based alternatives in the global market. This mini‐review provides a critical analysis of past and current progress to enhance furfural production from lignocellulosic biomass. First, important chemical and fuel products derived from the catalytic conversion of furfural are outlined. We then discuss the importance of developing integrated production strategies to co‐produce furfural with other valuable chemicals. Furfural formation and loss chemistries are explored to understand effective methods to improve furfural yields from pentosans. Finally, selected relevant commercial and academic technologies that promise to improve lignocellulosic furfural production are discussed. © 2013 Society of Chemical Industry

BACKGROUND: Biomass is the only renewable feedstock containing carbon, and therefore the only alternative to fossil‐derived crude oil derivatives. However, the main problems concerning the application of biomass for biofuels and bio‐based chemicals are related to transport and handling, the limited scale of the conversion process and the competition with the food industry. To overcome such problems, an integral processing route for the conversion of (non‐feed) biomass (residues) to transportation fuels is proposed. It includes a pretreatment process by fast pyrolysis, followed by upgrading to produce a crude‐oil‐like product, and finally co‐refining in traditional refineries.

RESULTS: This paper contributes to the understanding of pyrolysis oil upgrading. The processes include a thermal treatment step and/or direct hydroprocessing. At temperatures up to 250 °C (in the presence of H₂ and catalyst) parallel reactions take place including re‐polymerization (water production), decarboxylation (limited CO₂ production) and hydrotreating. Water is produced in small quantities (approx. 10% extra), likely caused by repolymerization. This repolymerization takes place faster (order of minutes) than the hydrotreating reactions (order of tens of minutes, hours).

CONCLUSIONS: In hydroprocessing of bio‐oils, a pathway is followed by which pyrolysis oils are further polymerized if H₂ and/or catalyst is absent, eventually to char components, or, with H₂/catalyst, to stabilized components that can be further upgraded. Results of the experiments suggest that specifically the cellulose‐derived fraction of the oil needs to be transformed first, preferably into alcohols in a ‘mild hydrogenation’ step. This subsequently allows further dehydration and hydrogenation. Copyright © 2010 Society of Chemical Industry

Fatty acids and their derivatives can be converted to renewable and carbon‐neutral fuel‐like hydrocarbons that are entirely fungible with fossil fuels. Typically, these hydrocarbon‐based biofuels are obtained through hydrotreating, a method which has the significant disadvantages of requiring problematic sulfided catalysts and high pressures of hydrogen. In recent years, decarboxylation/decarbonylation has been proposed as an alternative method, as this approach has the advantages of permitting the use of simpler catalysts and requiring less hydrogen than hydrotreating. In this contribution, the deoxygenation of fatty acids and their derivatives to fuel‐like hydrocarbons via decarboxylation/decarbonylation is critically reviewed. The main aspects discussed include the influence of the feed, catalyst, reactor system and reaction conditions on the decarboxylation/decarbonylation reaction, as well as the reaction mechanism and catalyst deactivation/regeneration. Copyright © 2012 Society of Chemical Industry