José Coca

Recovery of phenol from aqueous solutions using hollow fibre contactors

The purpose of this study is to characterise recovery of phenol from an aqueous solution using a hydrophobic polypropylene membrane contactor. The effects of temperature and hydrodynamics on the overall mass transfer coefficient were determined. Integration of the extraction and stripping stages was also carried out thereby allowing removal of more than 99% of the original phenol, while the organic phase is simultaneously regenerated.

A new integrated membrane process for producing clarified apple juice and apple juice aroma concentrate

An integrated membrane process for producing apple juice and apple juice aroma concentrates is proposed. The process involves the following operations: an integrated membrane reactor to clarify the raw juice; reverse osmosis (RO) to preconcentrate the juice up to 25°Brix; pervaporation (PV) to recover and concentrate aroma compounds, and a final evaporation step to concentrate apple juice up to 72°Brix. These operations were tested in laboratory and pilot plant units. Promising results were obtained with the membrane operations involved. In order to have an economic process assessment, the pilot plant units were assembled into an integrated unit and operated with raw apple juice. The products were more clear and brilliant than apple juice produced by conventional methods. The integrated membrane process also seemed to be more advantageous on the basis of economics than the conventional one.

Design and construction of a modular pilot plant for the treatment of oil-containing wastewaters☆

A modular pilot size plant involving coagulation/flocculation, centrifugation, ultrafiltration and sorption processes has been designed and constructed. The pilot plant can be used for the treatment of different water-based coolants and oily wastewaters, generated in metalworking processes and steel cold rolling operations. Different treatments are considered depending on the nature of the oily waste emulsion. The main advantage of the plant is its versatility, allowing the combination of several of the aforementioned treatments. It is a feasible waste management alternative with potential savings as a result of a better control of the elimination of oily wastes and water reuse, with the result of environmental and economic benefits.

Salicylic acid production by electrodialysis with bipolar membranes

Abstract Production of salicylic acid from sodium salicylate was carried out by electrodialysis (ED) using bipolar membranes (BPM). The process feasibility was tested using a laboratory ED-cell with a membrane area of 40 cm 2 . The performances of two commercial bipolar membranes (Tokuyama Soda and Stantech membranes) are compared. Current efficiencies for salicylic acid and caustic soda production are close for both bioolar membranes (80–90%), but differences are observed with respect to energy consumption which are related to the electrical characteristics of the membranes.

Solvent extraction of molybdenum and tungsten by Alamine 336 and DEHPA

Equilibrium data at 25°C have been obtained for the extraction of molybdenum and tungsten with Alamine 336 and DEHPA (di-2-ethylhexylphosphoric acid), and molybdenum-tungsten solutions with DEHPA from sulfuric acid solutions. The extractant (10% by volume) was dissolved in kerosene, and 2-ethylhexanol (2% by volume) was used as modifier. Extraction data are reported for initial concentration of molybdenum between 1 and 10 g 1−1 and tungsten between 5 and 10 g 1−1 as a function of initial pH, organic/aqueous phase volume ratio and tungsten/molybdenum ratio. Alamine 336 extracts both molybdenum (pH° 1–2) and tungsten (pH° 3) with a high yield, while DEHPA selectively extracts molybdenum at pH° 3. Optimal selectivity for the extraction of molybdenum in the presence of tungsten is achieved at pH° 3 and organic phase/aqueous phase volume ratio 12.

Ultrafiltration of a Waste Emulsified Cutting Oil using Organic Membranes

The influence of operating conditions on permeate flux was investigated using organic ultrafiltration membranes to treat a synthetic cutting-oil emulsion containing 0.05 to 0.8 wt. % oil. A commercial cutting oil, Alba-Kool, and four organic ultrafiltration membranes, two made of polysulfone (PM10 and PM30) and the other two of regenerated cellulose (YM10 andYM30), with cut-off sizes of 10 000 or 30 000 Dalton, were used.All experiments were performed in a commercially available stirred ultrafiltration cell. Within the range of operating conditions studied, it was found that the highest fluxes wereobtained at the following conditions: crossflow velocity (rotation speed) of 375 rpm, temperature of 40 °C andtransmembrane pressure of 0.1–0.15 MPa. Oil rejections between99 and 99.9% were obtained. Complete membrane regeneration wasachieved with a 2 vol. % aqueous solution of a commercial cleaning agent (Derquim+, Panreac).

A comparative study of reverse osmosis and freeze concentration for the removal of valeric acid from wastewaters

Abstract The recovery of valeric (n-pentanoic) acid from a synthetic aqueous solution simulating a wastewater stream in nylon manufacturing has been carried out using freeze concentration and reverse osmosis as separation processes. The concentration of valeric acid in aqueous solutions was in the range of 0.5–25 g/L. Reverse osmosis was carried out at 20 and 40°C and at a transmembrane pressure in the range of 1.3 to 6.0 MPa. The feed flow rate was 2 m/s in all the experiments. Although no membrane fouling was observed under the experimental conditions tested, a strong interaction of the acid with the membrane was noticeable. Rejections of the order of 90% were observed at 20°C, while values below even 50% were found at 40°C. The optimum performance for freeze concentration was determined, the best conditions being −10°C of subcooling temperature and 1012 kg/hm of feed flow. A model based on the heat transfer balance allows to predict the rate of ice crystallization. An economic analysis reveals that although freeze concentration consumes as much as five times the energy of reverse osmosis, which is compensated by the high costs of membrane replacement in reverse osmosis.

Liquid-liquid extraction of lactic acid with Alamine 336

The extraction of lactic acid from aqueous solutions by Alamine 336 dissolved in toluene was studied. Experiments were performed in the temperature range of 25-60°C and for two amine concentrations of 20 and 40% (v/v) in toluene. The extent to which the organic phase (amine+toluene) may be loaded with lactic acid is expressed as a loading ratio, Z. Z values are independent of the amine concentration and, hence, the extracted complex contains only one molecule of amine. Z decreases with increasing temperature. Experimental results indicate that the system presents overloading, i.e. Z>1. The extraction equilibrium may be interpreted as a result of consecutive formation of three acid-amine species with stoichiometries of 1:1, 2:1 and 3:1.

Treatment of a waste oil-in-water emulsion from a copper-rolling process by ultrafiltration and vacuum evaporation.

A process is proposed for the treatment of a waste oil-in-water (O/W) emulsion generated in an industrial copper-rolling operation. The use of demulsifier agents improves the subsequent treatment by techniques such as ultrafiltration (UF) or evaporation. The effluent COD is reduced up to 50% when the O/W emulsion is treated by UF using a flat 30 nm TiO(2) ceramic membrane (ΔP = 0.1 MPa) and up to 70% when it is treated by vacuum evaporation, after an emulsion destabilization pretreatment in both cases. Increases in the UF permeate flux and in the evaporation rate are observed when a chemical demulsifier is used in the pretreatment step. A combined process consisting of destabilization/settling, UF, and vacuum evaporation can yield a very high-quality aqueous effluent that could be used for process cooling or emulsion reformulation.

Recovery of Gallium From Coal Fly Ash By a Dual Reactive Extraction Process

The extraction of gallium from coal fly ash by leaching and extraction with commercial extractants Amberlite LA-2 and LIX 54N dissolved in kerosene was studied. Leaching of gallium and other metals from the fly ash was carried out with 6 M hydrochloric acid. The leaching liquor is first contacted with Amberlite LA-2 which extracts the gallium and iron. The iron is then precipitated with sodium hydroxide, while gallium remains in solution. Gallium is extracted selectively from the base solution with LIX 54; the resulting stripped solution contains 83% of the gallium present in the leaching liquor. A flow diagram for this dual-extraction process is proposed.