José R. Álvarez

Bio: José R. Álvarez is an academic researcher from University of Oviedo. The author has contributed to research in topics: Membrane & Nanofiltration. The author has an hindex of 15, co-authored 26 publications receiving 607 citations.

Membrane-assisted processing of xylooligosaccharide-containing liquors.

Abstract: Liquors from rice husk autohydrolyis, containing xylooligosaccharides, other saccharides, and nonsaccharide compounds, were subjected to two selected processing schemes to increase the proportion of substituted xylooligosaccharides in refined liquors. Nanofiltration through a ceramic membrane with a molecular mass cutoff of 1000 Da allowed simultaneous concentration and purification; this latter derived from the preferential removal of monosaccharides and nonsaccharide compounds. When liquors were nanofiltered to achieve a volume reduction factor of 5 operating at a transmembrane pressure of 14 bar, 58.6% of the nonsaccharide components and 20.9-46.9% of monosaccharides were kept in retentate, in comparison with 92% of xylooligosaccharides and glucooligosaccharides. When nanofiltered liquors were subjected to double ion-exchange processing, a final product with a nonsaccharide content near 9 kg/100 kg of nonvolatile components was obtained at a yield of 10.90 kg/100 kg oven dry rice husks. Alternatively, when nanofiltered liquors were subjected to ethyl acetate extraction and further double ion-exchange processing, a purified product with a nonsaccharide content of 5.66 kg/100 kg of nonvolatile components was obtained at a yield of 9.94 kg/100 kg oven dry rice husks. The nonsaccharide components remaining in the final concentrate were mainly made up of phenolic and nitrogen-containing compounds.

Industrial Applications of Porous Ceramic Membranes (Pressure‐Driven Processes)

Abstract: Publisher Summary This chapter discusses the industrial applications of porous ceramics membranes. Pressure-driven membrane processes are among the most mature membrane technologies. They are used for liquid separations and are generally classified into four categories: reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF), andmicrofiltration (MF). Pressure-driven membrane processes at present have high industrial impact, with a market constantly growing. They are used in a wide range of separation processes and are considered among the best available technologies (BAT), in the European Union environmental recommendations because they present several advantages with respect to other separation processes. The main applications of RO are found in the desalination of brackish and seawater; the production of ultrapure water (electronic industry); concentration of food juice, sugars, and milk; and in the treatment of wastewater. The performance of the ceramic membrane-based systems depends on the separation and permeation properties of the membrane as well as its mechanical integrity. These properties depend on the selective top layer and on the support system on which the active separation layer is coated. Therefore, pore size, porosity, surface roughness, and mechanical properties—all are important parameters.

A review of pervaporation for product recovery from biomass fermentation processes

Abstract: Although several separation technologies are technically capable of removing volatile products from fermentation broths, distillation remains the dominant technology. This is especially true for the recovery of biofuels such as ethanol. In this paper, the status of an emerging membrane-based technology, called pervaporation, for this application is reviewed. Several issues and research priorities which will impact the ability of pervaporation to be competitive for biofuel recovery from fermentation systems are identified and discussed. They include: increased energy efficiency; reduction of capital cost for pervaporation systems; longer term trials with actual fermentation broths; optimized integration of pervaporation with fermentor; synergy of performing both alcohol recovery and solvent dehydration by pervaporation with dephlegmation fractional condensation technology; and updated economic analyses of pervaporation at various biofuel production scales. Pervaporation is currently viable for biofuel recovery in a number of situations, but more widespread application will be possible when progress has been made on these issues. Published in 2005 for SCI by John Wiley & Sons, Ltd.

Synthetic membranes for water purification : status and future

Abstract: Membrane technology offers the best options to "drought proof" mankind on an increasingly thirsty planet by purifying seawater or used (waste) water. Although desalination by reverse osmosis (RO) and wastewater treatment by membrane bioreactors are well established the various membrane technologies still need to be significantly improved in terms of separation properties, energy demand and costs. We can now define the ideal characteristics of membranes and advances in material science and novel chemistries are leading to increasingly effective membranes. However developments in membranes must be matched by improved device design and membrane engineering. It is likely that limitations in fluid mechanics and mass transfer will define the upper bounds of membrane performance. Nevertheless major advances and growth over the next 20 years can be anticipated with RO remaining as the key to desalination and reclamation, with other membrane processes growing in support and in niche areas.

Hydrothermal processing, as an alternative for upgrading agriculture residues and marine biomass according to the biorefinery concept: A review

Abstract: The concept of a biorefinery that integrates processes and technologies for biomass conversion demands efficient utilization of all components. Hydrothermal processing is a potential clean technology to convert raw materials such as lignocellulosic materials and aquatic biomass into bioenergy and high added-value chemicals. In this technology, water at high temperatures and pressures is applied for hydrolysis, extraction and structural modification of materials. This review is focused on providing an updated overview on the fundamentals, modelling, separation and applications of the main components of lignocellulosic materials and conversion of aquatic biomass (macro- and micro- algae) into value-added products.