Anna Witek-Krowiak

Application of response surface methodology and artificial neural network methods in modelling and optimization of biosorption process

A review on the application of response surface methodology (RSM) and artificial neural networks (ANN) in biosorption modelling and optimization is presented. The theoretical background of the discussed methods with the application procedure is explained. The paper describes most frequently used experimental designs, concerning their limitations and typical applications. The paper also presents ways to determine the accuracy and the significance of model fitting for both methodologies described herein. Furthermore, recent references on biosorption modelling and optimization with the use of RSM and the ANN approach are shown. Special attention was paid to the selection of factors and responses, as well as to statistical analysis of the modelling results.

State of the art for the biosorption process--a review.

In recent years, biosorption process has become an economic and eco-friendly alternative treatment technology in the water and wastewater industry. In this light, a number of biosorbents were developed and are successfully employed for treating various pollutants including metals, dyes, phenols, fluoride, and pharmaceuticals in solutions (aqueous/oil). However, still there are few technical barriers in the biosorption process that impede its commercialization and thus to overcome these problems there has been a steadily growing interest in this research field. This resulted in large numbers of publications and patents each year. This review reports the state of the art in biosorption research. In this review, we provide a compendium of know-how in laboratory methodology, mathematical modeling of equilibrium and kinetics, identification of the biosorption mechanism. Various mathematical models of biosorption were discussed: the process in packed-bed column arrangement, as well as by suspended biomass. Particular attention was paid to patents in biosorption and pilot-scale systems. In addition, we provided future aspects in biosorption research.

Removal of microelemental Cr(III) and Cu(II) by using soybean meal waste – Unusual isotherms and insights of binding mechanism

In the present study soybean meal (SBM) waste has been used for the removal Cr(III) and Cu(II) from aqueous solutions. Effect of variable parameters including pH, contact time, biomass dose and initial concentration of metal ions were studied. Biosorption kinetics was very fast and the kinetics data were successfully modeled using nonlinear pseudo-second-order model. A series of isotherm experiments revealed that pH 5 favored Cr(III) and Cu(II) biosorption and the affinity order of SBM was Cu(II) > Cr(III). Biosorption mechanism was confirmed by the functional group blocking, FTIR and scanning electron microscopy/energy-dispersive X-ray results. The biosorption mechanism was due to (i) ion-exchange, (ii) chelation by carboxyl and hydroxyl groups present on the SBM surface, (iii) further precipitation of metal ions on the surface of biomass. Our results revealed that SBM could be employed as an effective and low-cost biosorbent for removal of Cr(III) and Cu(II) from contaminated effluents.

Biosorption of malachite green by eggshells: Mechanism identification and process optimization

In the present work, eggshells were used to remove a dye (malachite green) from wastewater. The study was focused on identification and describing the binding mechanism of the dye by eggshells in a biosorption process optimized by Response Surface Methodology based on the Box-Behnken Design. The mechanism of biosorption was determined by characterization of the biosorbent before and after biosorption using scanning electron microscopy, X-ray diffraction analysis, the Brunauer-Emmett-Teller isotherm method, Fourier transform infrared spectroscopy. The second-order polynomial equation and 3D response surface plots were used to quantitatively determine the relationships between dependent and independent variables. The obtained results suggested the mechanism of wastewater treatment that included physical adsorption, alkaline fading phenomenon and microprecipitation. The results of the present study showed that waste eggshells have the potential to be used as an inexpensive but effective biosorbent useful in wastewater treatment.

Modelling and optimization of chromiumIII biosorption on soybean meal

In this investigation a waste biological material, soybean meal, was applied as a biosorbent for heavy metal ions (CrIII). The diffusive Webber-Morris model and the pseudo-II-order model suitably described the kinetics of CrIII ions binding on soybean meal. The Langmuir-Freundlich equation was valid for the description of the isotherm. Inductively coupled plasma optical emission spectroscopy (ICP-OES), FTIR and scanning electron microscopy with an energy dispersive X-ray analytical system (SEM-EDX) were used in order to identify the mechanism of the metal ions binding. The analysis of the composition of the enriched soybean meal confirmed the contribution of ion exchange in the biosorption process. Three-variable-three-level Box-Behnken design was used to determine the optimal conditions for biosorption of CrIII on soybean meal. The optimal conditions for predicted maximum Cr3+ uptake (61.07 mg g−1) by soybean meal were estimated by Matlab and established as temperature of 38.04°C, initial metal concentration 500 mg L−1 and biosorbent dosage 1 g L−1.Graphical abstract

Biosorption of malachite green from aqueous solutions by pine sawdust: equilibrium, kinetics and the effect of process parameters

abstract The study offers the use of Scots Pine (Pinus silvestris) sawdust as a biosorbent for the removal of cationic dye, malachite green, from aqueous solutions. The effects of process parameters, such as contact time, sorbent concentration, initial dye concentration, pH, temperature, salinity and surfactant addition, on the biosorption process were determined. The experimental biosorption kinetics and equilibrium results were described by a range of mathematical models. The equilibrium data were best described by the Langmuir-Freundlich model, while the kinetics was best described by the pseudo-second-order model. The maximum sorption capacity of sawdust was 71.67 mg/g. An increase in pH values results in the rise of biosorption degree, mostly below pH 5. Addition of inorganic salts results in a drop in sorption capacity, but for concentrations higher than 0.5% w/w, the uptake increases along with an increase in salt concentration. The presence of an ionic surfactant (sodium dodecyl benzene sulphonate...

Advances in biosorption of microelements – the starting point for the production of new agrochemicals

Abstract This paper reports the advances in biosorption of trace elements to produce value-added products for agriculture. Innovative fertilizers and dietary feed supplements can be produced by biosorption, where micronutrients are bonded with biological material. The process is controlled by the equilibrium between functional groups and micronutrient ions (e.g., Cu(II), Mn(II), Fe(II), Zn(II)), yielding the products with controlled release properties. The latter assumes high bioavailability and low toxicity to plants and animals. This makes it possible to biofortify food of plant and animal (meat, milk, eggs) origin with microelements and produce a new generation of functional food, rich in microelements. Regulatory issues related with micronutrient dietary feed supplements and fertilizers were discussed. Special attention has been paid to micronutrient deficiencies in plant cultivation and animal nutrition and to the methods of overcoming this problem. The applicability of biosorption to supplement bioavailable form of nutritionally significant elements was discussed. Current developments of biosorption-based technologies for agriculture were presented.

Enrichment of soybean meal with microelements during the process of biosorption in a fixed-bed column.

The aim of the present investigation was to enrich the mineral content of soybean meal with essential chromium and copper metal ions by a biosorption technique in a fixed-bed column. The values of column parameters were determined at various process conditions: pH, temperature, flow rate, and concentration of the feed solution; mass and size of the particles of the bed to determine the breakthrough curves. Biosorption efficiency at optimal conditions (pH 5.0, temperature = 20 °C, Cr(3+) concentration = 200 mg/L, flow rate = 10 mL/min, and sorbent mass = 40 g) was 71.4%. Maximum uptake for Cr(III) and Cu(II) obtained in column was around 15.3 and 12.3 mg/g, respectively. The model constants obtained in this study can be used for design pilot plant systems. Soybean enriched with microelements by biosorption can be considered as biological carrier of microelements and therefore used as the component of livestock feed.

Concentration of natural aroma compounds from fruit juice hydrolates by pervaporation in laboratory and semi-technical scale. Part 1. Base study

The first article of a two-article series presents pervaporation (PV) of volatile aroma compounds from fruit juice hydrolates (plum, apple, blackcurrant and cherry). The purpose of this research was to evaluate the effectiveness of fruit juice hydrolates separation on a laboratory scale (inert gas flow pervaporation system) and semi-technical (vacuum pervaporation system) by means of pervaporation. To create precise matrices for hydrolates before and after pervaporation for each of the separated systems, solid phase microextraction (SPME) technique and the gas chromatography-mass spectrometry (GC-MS) was applied. Sensory analysis confirmed improvement of aroma note of concentrated permeates as compared to feed hydrolates solutions. The results indicated that pervaporation may be applied in condensing aromatic water or fruit juice hydrolate, which may significantly enhance product quality and lengthen shelf life.