The ability of vegetable wastes such as grape stalks and exhausted coffee to remove metals ions from synthetic aqueous solutions has been demonstrated in various studies performed by our research group [Villaescusa et al. 2004; Valderrama et al. 2010]. In this work, the performance of these wastes to remove nickel ions from an exhausted electroplating bath of a metal finishing industry from Barcelona (Spain) has been investigated.
The experiments were carried out at room temperature in packed bed flow-up columns of 250 mm of length and 25 mm internal diameter using grape stalk (GS) and exhausted coffee wastes (EC) particle size 0.5-1.0 mm and 0.8-1.0 mm, respectively. In all experiments nickel concentration was kept constant about 5500 mg dm-3 and pH, flow rate, and bed height were varied in order to predict nickel ions transport in the column. Breakthrough curves were successfully described by Bed depth service time (BDST), Thomas and Yoon Nelson models [Zhe et al. 2013]. Desorption studies were performed by using 0.1 mol dm-3 HCl as elution solution at the same flow-rate used for sorption experiments.
The results obtained demonstrated that, in the studied experimental conditions, variation of initial pH, flow rate and bed height did not lead to significant differences on sorption capacity. The sorbent sorption capacity was higher for GS (20 mg•g-1) than for EC (12 mg•g-1) and metal recovery from the column was close to 50% and 10% for GS and EC, respectively.
During the last years our research group has been studying the use of industrial vegetable wastes as grape stalks and exhausted coffee to remove metals ions such as Ni(II), Cu(II), Pb(II), Zn(II), Cd(II) or Cr(VI) and Cr(III) in aqueous solution from the point of view to use these wastes as biosorbents in a low cost alternative to activated carbon for wastewater treatment. The optimal experimental conditions for the removal of each of these metal ions in synthetic solutions by using both biosorbents were determined in previous studies . In this work, the performance of grape stalks and exhausted coffee for the removal of nickel ions from an exhausted electroplating bath of a metal finishing industry from Barcelona (Spain) has been investigated.
Batch and column experiments were carried out at room temperature by using grape stalk wastes (particle size 0.8-1.0 mm), meanwhile in the case of exhausted coffee, two different particle size ranges were used, 0.25-0.50 mm and 0.50-1.00 mm for batch and column experiments, respectively.
Kinetics and equilibrium studies were carried out in batch mode to determine the equilibrium contact time and to obtain the sorption capacity of sorbents. The data in both studies have been treated by using different models. Column experiments were designed to establish the optimal condition for the treatment of the industrial wastewater. The experiments were performed in packed bed up flow columns of different internal diameter and bed depth in order to predict the transport and sorption parameters. In all column experiments the flow rate was around 11 mL h-1. From perspective of process modelling, the dynamic behavior was described in terms of breakthrough curves. The bed depth service time (BDST), Thomas and Yoon Nelson models were used to analyze the experimental data and to determine model parameters.
Batch results show that about 1hour was the time needed to reach equilibrium when using grape stalks and around 15 h when using exhausted coffee. In the case of exhausted coffee, the pH solution decreased during the sorption process from initial pH 5,5 to lower pH than the corresponding pHpzc (point zero charge). To avoid this, pH solution was controlled to a constant pH 5,5 and the equilibrium were achieved in 1h.
Kinetic data of both sorption processes fit pseudo-second order model, indicating that chemisorption could be rate limiting in the sorption step.
Equilibrium data of nickel sorption onto grape stalks and exhausted coffee fit adequately Langmuir model, indicating monolayer coverage. Results showed that maximum sorption capacity of grape stalks (4,8 10-2 mmol/g; 2,84 mg/g) is slightly higher than exhausted coffee (2,9 10-2 mmol/g; 1,70 mg/g). The maximum nickel sorption capacity of both sorbents was reduced to 50% compared to maximum sorption capacity determined using synthetic Ni(II) solutions. Thus, grape stalks and exhausted coffee performance for the removal of Ni(II) from the studied industrial wastewater are negatively affected by the presence of other compounds in the industrial wastewater.
In column experiments, the best results were obtained by using 2.8 cm internal diameter columns and bed depth 6 cm and 8 cm for grape stalks and exhausted coffee, respectively. Breakthrough curves were successfully modelled by the proposed columns models. The results obtained demonstrated that grape stalks sorption capacity was higher than exhausted coffee but this one presented a higher sorption rate.
Our research groups have been working in the developing of sustainable and cheap technology based on vegetable wastes as sorbents for the removal of metal ions from industrial wastewater. Specifically, grape stalk wastes, generated in the wine production, resulted to be an efficient sorbent for the removal of hexavalent chromium and divalent heavy metal ions. Conventionally, analytical methods as FAAS, ICP-OES and FIA with potentiometric detection (FIP) have been used in the monitoring of metal biosorption processes. However, the limitations of these methods when working with real samples, specifically on multiparametric or speciation analysis, have led us to consider the use of electronic tongues (ET) based on arrays of multiple sensors showing cross-selectivity, and simultaneous analysis based on bivariate analysis and spectrophotometric detection. Thus, two different approaches have been developed.
First, a new methodology for the simultaneous and automated monitoring of biosorption processes based on flow-injection potentiometry (FIP) and electronic tongue detection (ET) is presented. A fixed-bed column filled with grape stalks is used as the biosorption setup to remove the metal mixtures from the influent solution. The monitoring system consists in a computer controlled-FIP prototype with the ET based on an array of up to 9 flow-through ion-selective and generic response electrodes, plus an artificial neural network (ANN) response model. Electrodes with cross-response to Cu2+, Cd2+, Zn2+, Pb2+ and Ca2+ are used, and a dynamic treatment of the kinetic components of the FIP transient peak signals is incorporated, in which selected coefficients obtained from the Fourier transform are used to feed the ANN model.
Real-time monitoring of single, binary and ternary mixtures is achieved satisfactorily using the reported system, obtaining the corresponding breakthrough curves. Analytical performance is verified against conventional spectroscopic techniques, with good concordance of the obtained breakthrough curves with relative error values below 7%.
The second approach is based on sequential injection analysis (SIA) and spectrophotometric detection for the monitoring of Cr(VI) and Cr(III). Thus, the analysis is performed in two steps: first, Cr(VI) is directly measured and, in a second step, Cr(III) is oxidized to Cr(VI) and total chromium is then determined. For quantification, a calibration technique by bivariate analysis based on Multiple Linear Regression (MLR) has been used, with reproducibilities higher than 95%.
In this communication, a new methodology for the simultaneous and automated monitoring of biosorption processes of multimetal mixtures of polluting heavy metals on vegetable wastes based on flow-injection potentiometry (FIP) and electronic tongue detection (ET) is presented. A fixed-bed column filled with grape stalks from wine industry wastes is used as the biosorption setup to remove the metal mixtures from the influent solution. The monitoring system consists in a computer controlled-FIP prototype with the ET based on an array of 9 flow-through ion-selective electrodes and electrodes with generic response to divalent ions placed in series, plus an artificial neural network response model. The cross-response to Cu2+, Cd2+, Zn2+, Pb2+ and Ca2+ (as target ions) is used, and only when dynamic treatment of the kinetic components of the transient signal is incorporated, a correct operation of the system is achieved. For this purpose, the FIA peaks are transformed via use of Fourier treatment, and selected coefficients are used to feed an artificial neural network response model...
In this communication, a new methodology for the simultaneous and automated monitoring of biosorption processes of multimetal mixtures of polluting heavy metals on vegetable wastes based on flow-injection potentiometry (FIP) and electronic tongue detection (ET) is presented. A fixed-bed column filled with grape stalks from wine industry wastes is used as the biosorption setup to remove the metal mixtures from the influent solution. The monitoring system consists in a computer controlled-FIP prototype with the ET based on an array of 9 flow-through ion-selective electrodes and electrodes with generic response to divalent ions placed in series, plus an artificial neural network response model. The cross-response to Cu2+, Cd2+, Zn2+, Pb2+ and Ca2+ (as target ions) is used, and only when dynamic treatment of the kinetic components of the transient signal is incorporated, a correct operation of the system is achieved. For this purpose, the FIA peaks are transformed via use of Fourier treatment, and selected coefficients are used to feed an artificial neural network response model. Real-time monitoring of different binary (Cu2+/ Pb2+), (Cu2+/ Zn2+) and ternary mixtures (Cu2+/ Pb2+/ Zn2+), (Cu2+/ Zn2+/ Cd2+), simultaneous to the release of Ca2+ in the effluent solution, are achieved satisfactorily using the reported system, obtaining the corresponding breakthrough curves, and showing the ion-exchange mechanism among the different metals. Analytical performance is verified against conventional spectroscopic techniques, with good concordance of the obtained breakthrough curves and modeled adsorption parameters.
de la Torre, F.; Florido, A.; Fiol, N.; Poch, J.; Olivella, M.À; Villaescusa, I. International Conference on Flow Injection Analysis p. 130-131 Data de presentació: 2013-09-16 Presentació treball a congrés
An automated flow injection potentiometric (FIP) system with electronic tongue detection (ET) is used for the monitoring of biosorption processes of heavy metals on vegetable wastes. Grape stalk wastes are used as biosorbent to remove Cu2+ ions in a fixed-bed column configuration. The ET is formed by a 5-sensor array with Cu2+ and Ca2+-selective electrodes and electrodes with generic response to heavy-metals, plus an artificial neural network response model of the sensor's cross-response. The real-time monitoring of both the Cu2+ and the cation exchanged and released (Ca2+) in the effluent solution is performed by using flow-injection potentiometric electronic tongue system. The coupling of the electronic tongue with automation features of the flow-injection system allows us to accurately characterize the Cu2+ ion-biosorption process, through obtaining its breakthrough curves, and the profile of the Ca2+ ion release. In parallel, fractions of the extract solution are analysed by spectroscopic techniques in order to validate the results obtained with the reported methodology. The sorption performance of grape stalks is also evaluated by means of well-established sorption models.
'The shortage of drinking water in many regions on the planet constitutes a real problem and hazard. The use of seawater, brackish water and wastewater for human consumption is not a new concept. In spite of the success of membrane technology in water reclamation, membrane separation systems suffer from a serious problem: membrane fouling. The main downside is an inevitabe increase in operation and maintenance costs as well as an adverse effect on the lifespan of the membrane (harsh cleaning treatment). LbLBRANE is an ambitious project ensuring competent input right from the membrane concept down to lab-scale production and optimisation before scaling-up in pilot plants for end users. LbLBRANE applies novel nanotechnology tools, namely the layer-by-layer (LbL) technology to develop a versatile and generic procedure for the fast fabrication of low-cost, stable, chemical-resistant polyelectrolyte membranes. The LbL technology is the way to go for a bottom-up nano-engineered membrane whereby the modification is performed stepwise in a controlled manner - the thickness can be finely tuned by the number of layers deposited, the architecture of the film can be compartmentalised by incorporating functional species (polyelectrolyte as well as nanoparticles with specific functions, such as antibacterial properties) and the morphology of the film can be modulated via the pH, charge density and type of polyelectrolyte pairs to create pore size (hence permeability) tailored according to the specific need of the membranes. Our concern is focused towards high performance, regenerable membranes which could be cleaned in-situ and hybrid membranes with extremely high flux with high permselectivity and mechanical robustness. The ultimate aim is towards implementation of LbL on large industrial scale, from module design and construction to end user, especially for water reuse and metal/acid recovery.'
Wilson, D.; Florido, A.; Valderrama, C.; Fernandez de Labastida, M.; Alegret, S.; del Valle, M. International Symposium on Olfaction and Electronic Nose p. 98-99 DOI: 10.1063/1.3626320 Data de presentació: 2011-05-04 Presentació treball a congrés
Florido, A.; Vernet, J.; Fernandez de Labastida, M.; Valderrama, C.; Wilson, D.; del Valle, M. Ibero-American Congress on Sensors p. 671-675 Data de presentació: 2010-11-09 Presentació treball a congrés
Miralles, N.; Valderrama, C.; Casas, I.; Martinez, M.; Florido, A. Journal of chemical and engineering data Vol. 55, num. 9, p. 3548-3554 DOI: 10.1021/je100200w Data de publicació: 2010-09 Article en revista
Grape stalk wastes generated in the wine production process were used for the removal of cadmium and
lead ions from aqueous solutions. The experimental breakthrough curves (BTC) were obtained from fixedbed
columns. Experiments were carried out to evaluate the influence of both inlet metal concentration and
sorbent particle size. The experimental data were fitted to the Thomas model, a well-established fixed-bed
sorption model. The theoretical sorption capacities obtained by the Thomas model were in good agreement
with the breakthrough capacities determined from the sorption data. The CXTFIT code was used to determine
the transport and sorption parameters of the convective-dispersive equation (CDE) and the two-site
deterministic nonequilibrium (TSM/CDE) model by adjusting the models to the experimental breakthrough
curves. The results showed that sorption capacities as well as both transport and sorption parameters were
affected by the initial metal concentration as well as by the sorbent particle size.
Florido, A.; Valderrama, C.; Nualart, S.; Velazco Molina, L.; Arias de Fuente, O.; del Valle, M. Analytica chimica acta Vol. 668, num. 1, p. 26-34 DOI: 10.1016/j.aca.2010.01.019 Data de publicació: 2010-05-23 Article en revista
Valderrama, C.; Arévalo, J.; Casas, I.; Martinez, M.; Miralles, N.; Florido, A. Journal of hazardous materials Vol. 174, num. 1-3, p. 144-150 DOI: 10.1016/j.jhazmat.2009.09.028 Data de publicació: 2010-02 Article en revista
Florido, A.; Valderrama, C.; Arévalo, J.; Casas, I.; Martinez, M.; Miralles, N. Chemical engineering journal Vol. 156, num. 2, p. 298-304 DOI: 10.1016/j.cej.2009.10.020 Data de publicació: 2010-01 Article en revista
Jiménez, C.; Moreno, L.; Haro, C.; Muñoz, X.; Florido, A.; Rivas, P.; Fernández, A.; Martín, P.; Bratov, A.; Domínguez, C. Sensors and actuators B. Chemical Vol. 91, num. 1-3, p. 103-108 Data de publicació: 2003-06 Article en revista