Pastor-Villegas J.,University of Extremadura |
Meneses Rodriguez J.M.,University of Extremadura |
Meneses Rodriguez J.M.,French National Center for Scientific Research |
Pastor-Valle J.F.,University of Extremadura |
And 3 more authors.
Journal of Analytical and Applied Pyrolysis | Year: 2010
We have studied the chemical composition, the surface chemistry and the pore structure of holm-oak chars and eucalyptus chars prepared at final heating temperature in the range of 250-1000 °C from two commercial wood charcoals. Our study also includes adsorption-desorption of water vapour at 25 °C on the resulting chars. The samples were characterised by chemical analyses, Fourier transform infrared spectroscopy, adsorption (carbon dioxide, 273 K), mercury porosimetry and scanning electron microscopy. The Dubinin-Serpinsky equation (DS-2) and the Dubinin-Astakhov (DA) equation were applied to analyse the water adsorption data. The final heating temperature affects the chemical composition, the surface chemistry and the pore structure of each char series differently; the differences are of less significance at the highest temperature. The adsorption-desorption of water vapour at 25 °C reflects well the changes produced in the chars; the adsorption occurs in the micropores, and in the non-micropore structure at relative pressures higher than 0.95. The shape of the adsorption isotherms is largely dependent on the microporosity; it changes gradually from type II to type V for the chars with poorly developed microporosity (holm-oak chars), and it is more of type V for the chars with highly developed microporosity (eucalyptus chars). The DS-2 equation fails if type V is less defined, while the DA equation is always applicable and provides micropore volumes close to those determined at p/p0 = 0.95. Hysteresis is always observed; chemisorption occurs: the desorption line begins at saturation pressure and in general tends to meet near zero relative pressures. © 2010 Elsevier B.V. All rights reserved.
De Torres-Socias E.,CIEMAT |
Fernandez-Calderero I.,CIEMAT |
Oller I.,CIEMAT |
Oller I.,University of Almeria |
And 4 more authors.
Chemical Engineering Journal | Year: 2013
Remediation of cork boiling wastewater was studied as an example of complex industrial wastewater treatment by applying a protocol based on a combination of advanced technologies and chemical-biological assays. Solar photo-Fenton and ozone (alone or in combination with hydrogen peroxide at different pH conditions), at pilot plant scale have been used as chemical oxidation step. Additionally, the effect of a physic-chemical pre-treatment using different flocculants (FeSO4 and FeCl3) was evaluated. Although physic-chemical pre-treatment with Fe3+ provided good removals of COD, DOC and TSS, it was found that it did not enhance solar photo-Fenton post-treatment. On the contrary, ozone-based process was improved after physic-chemical pre-treatment with Fe3+, attaining higher degradation efficiencies with lower ozone consumptions for the combination with O3 at initial pH 7. Toxicity and biodegradability assays were performed to evaluate possible variations along the oxidation processes. After solar photo-Fenton treatment, toxicity and biodegradability remained constant at their initial values. Then, Zahn-Wellens test was carried out to study long term biodegradability and possible biomass adaptation to the partially photo-treated effluent. Decrease in toxicity values and short term biodegradability enhancement were observed for cork boiling wastewater treated by ozonation systems. © 2013 Elsevier B.V.
De Torres-Socias E.,CIEMAT |
Cabrera-Reina A.,University of Almeria |
Trinidad M.J.,Instituto del Corcho |
Yuste F.J.,Instituto del Corcho |
And 4 more authors.
Environmental Science and Pollution Research | Year: 2014
Solar photo-Fenton process has been extensively reported to be highly efficient in the remediation of complex industrial wastewater containing several families of pollutants such as pharmaceuticals, dyes, pesticides, derivatives of wine, etc. Moreover, solar photo-Fenton mathematical modelling regarded as a powerful tool for scaling-up and process control purposes is hindered by the complexity and variability of its reaction mechanism which depends on the particular wastewater under study. In this work, non-biodegradable cork boiling wastewater has been selected as a case study for solar photo-Fenton dynamic modelling by using MATLAB® software. First of all physic-chemical pretreatment was applied attaining chemical oxygen demand (COD) reductions between 43 and 70 % and total suspended solid (TSS) reductions between 23 % and 59 %. After solar photo-Fenton treatment, COD decreased between 45 and 90 % after consumptions of H2O2 varying around 1.9 and 2.4 g/L. Individual calibration of the semi-empirical model by using experimental results made it possible to perfectly predict hydrogen peroxide variations throughout the treatment. It must be highlighted that slight deviations between predictions and experimental data must be attributed to important changes in wastewater characteristics. © 2014 Springer-Verlag Berlin Heidelberg.