Catalytic aqueous-phase reforming (APR) produces higher quality hydrogen (with less carbon monoxide) and carbon dioxide from weak solutions of bio-carbohydrates in a single reactor at low temperatures. It provides a good opportunity for the effective valorisation of biomass-derived products. It is advantageous than steam reforming because it saves energy by avoiding vaporization of the biofeed and lowers cost by precluding an extra water gas shift reactor. As evident from the numerous published works during the past decade, there is growing academic and industrial interest in the APR process. This review updates recent literature on APR of many biomass surrogates such as glycerol, ethylene glycol, sorbitol, ethanol and glucose. Most works focused on the development of efficient catalysts for selective hydrogen production and they were deliberated comprehensively. Key insights into improved catalysts and reaction conditions were highlighted. New inferences on the thermodynamic, kinetic and reactor engineering aspects of the APR process were analysed too. This thorough appraisal of the current literature, which is hitherto missing, will surely contribute to the development of the next generation of catalysts and reactors for commercial applications of the APR process.
Maria Carolina de Albuquerque Wanderleya
José Manoel Wanderley Duarte Netoa
José Luiz de Lima Filhoa
Carolina de Albuquerque Limab
José António Couto Teixeirac
Ana Lúcia Figueiredo Portod
Specific proteases capable of degrading native triple helical or denatured collagen have been required for many years and have a large spectrum of applications. There are few complete reports that fully uncover production, characterization and purification of fungi collagenases. In this review, authors searched through four scientific on line data bases using the following keywords (collagenolytic OR collagenase) AND (fungi OR fungus OR fungal) AND (production OR synthesis OR synthesize) AND (characterization). Scientific criteria were adopted in this review to classify found articles by score (from 0 to 10). After exclusion criteria, 21 articles were selected. None obtained the maximum of 10 points defined by the methodology, which indicates a deficiency in studies dealing simultaneously with production, characterization and purification of collagenase by fungi. Among microorganisms studied the non-pathogenic fungi Penicillium aurantiogriseum and Rhizoctonia solani stood out in volumetric and specific collagenase activity. The only article found that made sequencing of a true collagenase showed 100% homology with several metalloproteinases fungi. A clear gap in literature about collagenase production by fungi was verified, which prevents further development in the area and increases the need for further studies, particularly full characterization of fungal collagenases with high specificity to collagen.
Ioannis Anastopoulos
Vasileios A. Anagnostopoulos
Amit Bhatnagar
Athanasios C. Mitropoulos
George Z. Kyzas
Water pollution is still a serious problem for the entire world. Adsorption technology is a promising process which is based on the fabrication of novel, cheap, non-dangerous and highly sorptive materials for application in wastewater purification processes. Nanomaterials are functional groups which find use in many important fields such as medicine, food processing and agriculture. This review collects information from published works about the use of carbon nanotubes as efficient and promising adsorbents in chromium removal from (real or synthesised) wastewater. For this purpose, isotherm (Langmuir, Freundlich, etc.), kinetic (pseudo-first-, second-order, etc.), thermodynamic (free-energy Gibbs, enthalpy, entropy) and desorption–regeneration studies were discussed in detail. Moreover, significant factors such as pH, agitation time, temperature, adsorbent dosage and initial dye concentration are also reported extensively. The maximum monolayer adsorption capacities of Cr(III) and Cr(VI) ions were 0.39–238.09 and 1.26–370.3 mg/g, respectively. The absolute values of ΔG0 and ΔH0 ranged 0.237–48.62 and 0.16–58.43 kJ/mol, respectively.
van Dun, Kim; Bodranghien, Florian; Manto, Mario; Mariën, Peter
Transcranial magnetic and electric stimulation of the brain are novel and highly promising techniques currently employed in both research and clinical practice. Improving or rehabilitating brain functions by modulating excitability with these noninvasive tools is an exciting new area in neuroscience. Since the cerebellum is closely connected with the cerebral regions subserving motor, associative, and affective functions, the cerebello-thalamo-cortical pathways are an interesting target for these new techniques. Targeting the cerebellum represents a novel way to modulate the excitability of remote cortical regions and their functions. This review brings together the studies that have applied cerebellar stimulation, magnetic and electric, and presents an overview of the current knowledge and unsolved issues. Some recommendations for future research are implemented as well.
Contamination of natural waters with arsenic, which is both toxic and carcinogenic, is widespread. Among various technologies that have been employed for arsenic removal from water, such as coagulation, filtration, membrane separation, ion exchange, etc., adsorption offers many advantages including simple and stable operation, easy handling of waste, absence of added reagents, compact facilities, and generally lower operation cost, but the need for technological innovation for water purification is gaining attention worldwide. Nanotechnology is considered to play a crucial role in providing clean and affordable water to meet human demands. This review presents an overview of nanoparticles and nanobased adsorbents and its efficiencies in arsenic removal from water. The paper highlights the application of nanomaterials and their properties, mechanisms, and advantages over conventional adsorbents for arsenic removal from contaminated water. =20