The aim of this study was to evaluate and compare the efficiency of two types of vertical downflow wetlands (VDFWs) (with the presence of ligninolytic fungus Trametes versicolor and planted with Iris sibirica) for the treatment of tequila vinasses (TVs) as a secondary treatment; control systems with only a filter medium were also included. The systems operated with a 7-day run/resting mode of operation. Various water quality parameters were analyzed in both the influent and the effluents, namely total suspended solids (TSS), chemical oxygen demand (COD), biological oxygen demand (BOD5), total organic carbon (TOC), pH, electrical conductivity (EC), true color and turbidity, total phosphorus (TP), total nitrogen (TN), etc. The two types of VDFWs as well as the control treatment were effective in reducing the different pollutants (p < 0.05); however, planted systems showed a tendency toward higher efficiencies. With an influent concentration of 49,000 mg L−1 and an organic loading rate of 4942 g COD m−2d−1, the COD reduction was around 40% in the planted systems, while in the other two, the reduction was 35%. Furthermore, TSS removals were 36, 20 and 16% in the VDFWs with vegetation, ligninolytic fungus and control systems, respectively. These results suggest that the fungus Trametes versicolor did not develop the desirable enzymatic expression for pollutant removal, probably as a result of the absence of aerobic conditions in the systems. Therefore, more research is needed to achieve a better fungal performance in VDFWs.

Most diseases that affect human beings across the world are now treated with drugs of organic origin. However, some of these are associated with side effects, toxicity, and resistance phenomena. For the treatment of many illnesses, the development of new molecules with pharmacological potential is now an urgent matter. The biological activities of metal complexes have been reported to have antitumor, antimicrobial, anti-inflammatory, anti-infective and antiparasitic effects, amongst others. Metal complexes are effective because they possess unique properties. For example, the complex entity possesses the effective biological activity, then the formation of coordination bonds between the metal ions and ligands is controlled, metal ions provide it with extraordinary mechanisms of action because of characteristics such as d-orbitals, oxidation states, and specific orientations; metal complexes also exhibit good stability and good physicochemical properties such as water solubility. Platinum is a transition metal widely used in the design of drugs with antineoplastic activities; however, platinum is associated with side effects which have made it necessary to search for, and design, novel complexes based on other metals. Copper is a biometal which is found in living systems; it is now used in the design of metal complexes with biological activities that have demonstrated antitumoral, antimicrobial and anti-inflammatory effects, amongst others. In this review, we consider the open horizons of Cu(II)- and Pt(II)-based complexes, new trends in their design, their synthesis, their biological activities and their targets of action.

Fungal infections have become a significant public health concern due to their increasing recurrence and harmful effects on plants, animals, and humans. Opportunistic pathogens (among others from the genera Candida and Aspergillus) can be present in indoor air, becoming a risk for people with suppressed immune systems. Engineered nanomaterials are novel alternatives to traditional antifungal therapy. In this work, copper(I) iodide (CuI) and a copper-doped titanium dioxide-copper(I) iodide (TiO2-Cu2+/CuI) composite nanomaterials (NMs)-were synthesized and tested as antifungal agents. The materials were synthesized using sol-gel (TiO2-Cu2+) and co-precipitation (CuI) techniques. The resulting colloids were evaluated as antifungal agents against Candida parapsilosis and Aspergillus niger strains. The NMs were characterized by XRD, HRTEM, AFM, and DLS to evaluate their physicochemical properties. The NMs present a high size dispersion and different geometrical shapes of agglomerates. The antifungal capacity of the NMs by the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) was below 15 µg/mL against Candida parapsilosis and below 600 µg/mL against Aspergillus niger for both NMs. Holotomography microscopy showed that the NMs could penetrate cell membranes causing cell death through its rupture and reactive oxygen species (ROS) production. Cytotoxicity tests showed that NMs could be safe to use at low concentrations. The synthesized nanomaterials could be potential antifungal agents for biomedical or environmental applications.

A novel stochastic model is proposed to characterize the adsorption kinetics of pollutants including dyes (direct red 80 and direct blue 1), fluoride ions, and cadmium ions removed by calcium pectinate (Pec-Ca), aluminum xanthanate (Xant-Al), and reed leaves, respectively. The model is based on a transformation over time following the Ornstein-Uhlenbeck stochastic process, which explicitly includes the uncertainty involved in the adsorption process. The model includes stochastic versions of the pseudo-first-order (PFO), pseudo-second-order (PSO), and pseudo- n -order (PNO) models. It also allows the estimation of the adsorption parameters, including the maximum removal capacity ( q e ), the adsorption rate constant ( k n ), the reaction pseudoorder ( n ), and the variability sigma 2 . The model fitted produced R 2 values similar to those of the nonstochastic versions of the PFO, PSO, and PNO models; however, the obtained values for each parameter indicate that the stochastic model better reproduces the experimental data. The q e values of the Pec-Ca-dye, Xant-Al-fluoride, and reed leaf-Cd+2 systems ranged from 2.0 to 9.7, 0.41 to 1.9, and 0.04 and 0.29 mg/g, respectively, whereas the values of k n ranged from 0.051 to 0.286, 0.743 to 75.73, and 0.756 to 8.861 (mg/g)1-n /min, respectively. These results suggest a variability in the parameters q e and k n inherent to the natures of the adsorbate and adsorbent. The obtained n values ranged from 1.13 to 2.02 for the Pec-Ca-dye system, 1.0-3.5 for the Xant-Al-fluoride system, and 1.8-3.8 for the reed leaf-Cd+2 system. These ranges indicate the flexibility of the stochastic model to obtain fractional n values, resulting in high R 2 values. The variability in each system was evaluated based on sigma 2 . The developed model is the first to describe pollutant removal kinetics based on a stochastic differential equation.

In this work, the ability of pectin (Pec) to remove direct red 80 (DR80), Congo red (CR), methyl orange (MO), and methyl red (MR) was studied. The removal percentages under adequate pH and ionic strength conditions were as follows: DR80 (99.5%), CR (99.8%), MO (88.6%), and MR (68%), showing that this methodology is efficient to remove azo dyes. The proposed method included the addition of native Pec to the dye aqueous solution and the formation of a gel that occurred when a calcium salt solution was added. This gel retains the molecules adsorbed onto the molecular surface of Pec through hydrogen bonds and electrostatic and hydrophobic interactions. To our knowledge, it is the first time that the Zimm-Bragg model is used to describe the removal of azo dyes with native Pec. This model includes two parameters: Ku (nucleation constant), which is related to the tendency exerted by a dye molecule attached to the Pec to bind to other molecules present in the aqueous phase, and U (cooperativity parameter), which determines the aggregation capacity of the dye molecules already attached to the Pec. This model fits the experimental isotherms very well, suggesting that Pec binds single molecules and dye aggregates. The obtained results in the values of Ku ranged from 922 mol/kg (MR) to 1,157,462 mol/kg (CR), and U varied from 2.51 (MR) to 169.19 (MO). These results suggest that the use of Pec is a viable option to remove azo dyes from aqueous effluents and that the Zimm-Bragg model fits adequately the isotherms of dyes that have a high tendency to form aggregates.

Nejayote is the residual water from the nixtamalization process characterized by an alkaline pH (pH > 10) as well as high concentrations of dissolved and suspended organic matter (COD > 10 200 mg/L). As for the above mentioned, nejayote is considered within the more pollutants liquid effluents discharged into different water bodies. In this work, the effectiveness of sodium alginate and chitosan to reduce nejayote pollutants was tested. The application of alginate involved adsorption and gelation, which trapped suspended and dissolved material, and the use of chitosan implied an adsorption-precipitation phenomena. These polymers were used separately and sequentially. In the independent treatments, the alginate was more efficient than the chitosan, obtaining a COD removal of 61.43 ± 0.24 % and of 59.74 ± 0.36 % respectively. In sequential treatments, the removal efficiency of COD with alginate-chitosan was higher (70.19 ± 0.85 %) than that of the chitosan-alginate treatment (67.21 ± 0.24 %). On the other hand, the reduction in the amount of total solids allows that the effluent, after the processing, is within the maximum permissible limit established by the official Mexican standards NOM-002-SEMARNAT-1996 and NOM-001-SEMARNAT-1996.,This permits its discharge to urban or municipal sewerage systems and it can even be used for agricultural irrigation. The use of these biodegradable polymers is a viable option that has the potential to scale at the industrial level, contributing to the purification of discharges from the nixtamalization industry and to the benefit of the environment.

Nejayote is the residual water from the nixtamalization process characterized by an alkaline pH (pH > 10) as well as high concentrations of dissolved and suspended organic matter (COD > 10 200 mg/L). As for the above mentioned, nejayote is considered within the more pollutants liquid effluents discharged into different water bodies. In this work, the effectiveness of sodium alginate and chitosan to reduce nejayote pollutants was tested. The application of alginate involved adsorption and gelation, which trapped suspended and dissolved material, and the use of chitosan implied an adsorption-precipitation phenomena. These polymers were used separately and sequentially. In the independent treatments, the alginate was more efficient than the chitosan, obtaining a COD removal of 61.43 +/- 0.24 % and of 59.74 +/- 0.36 % respectively. In sequential treatments, the removal efficiency of COD with alginate-chitosan was higher (70.19 +/- 0.85 %) than that of the chitosan-alginate treatment (67.21 +/- 0.24 %). On the other hand, the reduction in the amount of total solids allows that the effluent, after the processing, is within the maximum permissible limit established by the official Mexican standards NOM-002-SEMARNAT-1996 and NOM-001-SEMARNAT-1996.,This permits its discharge to urban or municipal sewerage systems and it can even be used for agricultural irrigation. The use of these biodegradable polymers is a viable option that has the potential to scale at the industrial level, contributing to the purification of discharges from the nixtamalization industry and to the benefit of the environment.

In this article, visible light active, copper doped TiO2 nanoparticles are discussed as potential candidates for the tertiary treatment of industrial effluents. Our aim was to develop sustainable photocatalytic materials that exhibit excellent activity and biocompatibility. The photocatalysts were prepared using a two-step procedure: solgel synthesis followed by microwave hydrothermal treatment. Copper (Cu) was chosen as doping agent because it has been previously reported that Cu is a good doping element that improves the photocatalytic performance of TiO2. The incorporation of Cu into the TiO2 matrix was demonstrated by X ray photoelectron spectroscopy and a bandgap reduction down to 2.86 eV was achieved at relatively low doping levels (nominal 2.0%). A moderate photocatalytic activity was observed for the degradation of diclofenac and for the removal of dissolved organic matter contained in an industrial effluent. The removal efficiency of the nanoparticles increased linearly with the amount of copper doping. For instance after 7 h of illumination, diclofenac degradation efficiencies of 21.41, 28.95 and 33.26% were observed for TiO(2)eCu (1.0, 1.5 and 2.0%) respectively. Meanwhile, disinfection of the effluents was attained within five hours of treatment under visible light, in our irradiation conditions. Hydrogen peroxide improved the photocatalytic activity of the nanoparticles since the release of Cu2+ ions give rise to a combined degradation mechanism: photocatalysis + photo-Fenton. The lixiviation of Cu2+ ions was demonstrated by atomic absorption spectroscopy. Moreover, The Cu doped TiO2 nanostructures exhibited excellent antibacterial properties against both gram negative and positive bacteria and do not exert any cytotoxicity to human blood cells. The biocompatibility of the Cu doped TiO2 nanoparticles combined with their photocatalytic activity under room light illumination suits them as excellent candidates for the development of sustainable environmental remediation technologies.

Los colorantes azo representan entre 60 y 75 % de los colorantes producidos actualmente.Se utilizan ampliamente en la industria cosmética, del papel, optoelectrónica, textil, etc. Desafortunadamente una vez utilizados, debido a su alta resistencia a tratamientos convencionales de aguas residuales, contaminan los cuerpos de agua donde son descargados.En este reporte se utiliza alginato de sodio (ALG) para remover los colorantes azo rojo directo 80 (RD80), rojo congo (Rcongo) y rojo de metilo (Rmetilo).Estudios de espectroscopía UV-visible, FTIR y Raman ayudaron a elucidar los tautómeros involucrados en su remoción.Los porcentajes de remoción fueron: RD80 (99.9 % a pH = 12 y fuerza iónica= 0.1 M), Rcongo (99.7 % a pH = 12 y fuerza iónica = 0.1 M) y Rmetilo (14.9 % a pH = 7 y fuerza iónica = 0.1 M).El modelo de Zimm-Bragg describe adecuadamente las isotermas experimentales, sugiriendo la importancia de la agregación de los colorantes en su eficiencia de remoción.Adicionalmente, se comparó la eficiencia de remoción de siete colorantes azo y se encontró que moléculas con peso molecular elevado, con alta planaridad y carga positiva mostraron las mayores eficiencias de remoción.Lo anterior permite predecir cualitativamente a partir de las estructuras de colorantes azo, cuál de ellos será removido más eficientemente con el ALG.

The azo dyes represent between 60-75 %of the total of dyes produced nowadays. They are widely used in cosmetic industry, paper, optoelectronic, textile, etc. Unfortunately, due to their high resistance to the conventional treatments applied to wastewaters, they pollute the water bodies where are discharged. In this report, the sodium alginate (ALG) is evaluated for the removal of the azo dyes, Direct red 80 (DR80), Congo red (Rcongo) and Methyl red (Rmetilo). UV-visible, I. Ilk and Raman spectroscopic studies helped to elucidate the formation of tautomers, species responsible for their removal. The removal percentages were: DR80 (99.9 %at pH = 12 and ionic strength = 0.1 M), Rcongo (99.7 % at pH = 12 and ionic strength = 0.1 M), and Rmetilo (14.9 %at pH = 7 and ionic strength = 0.1 M). The Zimm-Bragg model described adequately the experimental isotherms, suggesting the importance of dye's aggregation in their removal efficiency. Additionally, the removal efficiency of seven azo dyes was compared and it was found that the highest removal efficiencies are achieved when dye molecules exhibit high molecular weight, planarity and are positively charged. This allows us to predict in a qualitative way, from the azo dye structures, which of them will be removed more efficiently with ALG.

The interaction among Xanthan (XANT) and three azo dyes: Direct blue 1 (DB1), Direct red 81 (DR81), and Direct black 22 (DB22) was studied. The Xanthan-dye-Al product was formed after the addition of AlCl3 to a Xanthan-Dye adduct containing solution. It was proposed that polyhydroxyoxoaluminum clusters named CAL-13 and CAL-30 react with this adduct producing a Xanthanate aluminum network, XANT-Al, and as a consequence a decrease in dye concentration in an aqueous medium was observed. The removal efficiencies obtained were the following: DB1 (99 %), DB22 (99 %) and DR81 (94 %), demonstrating that this dye removal method is very efficient. The Zimm-Bragg model adequately described the experimental data and the order observed in the Ku (nucleation) and U (aggregation) parameters from this model was the following: DB1>DB22> DR81. Evidence suggests that physicochemical properties of dyes such as charge, molecular weight, aggregation ability and the capacity of XANT-Al to trap dye molecules are involved in the high removal values. Moreover, the dye binding mechanisms include: electrostatic, hydrogen bonding and hydrophobic interactions that determine the magnitude of the parameters Ku and U. These findings suggest that the XANT polymer is a good option to remove azo dyes from an aqueous medium.

In this work, we report the synthesis, characterization and photocatalytic evaluation of visible light active iron-nitrogen co-doped titanium dioxide (Fe3+-TiO2−xNx) nanostructured catalyst. Fe3+-TiO2−xNx was synthesized using two different chemical approaches: sol-gel (SG) and microwave (MW) methods. The materials were fully characterized using several techniques (SEM, UV–Vis diffuse reflectance DRS, X-ray diffraction XRD, and X-ray photoelectron spectroscopy XPS). The photocatalytic activity of the nanostructured materials synthesized by both methods was evaluated for the degradation of amoxicillin (AMX), streptomycin (STR) and diclofenac (DCF) in aqueous solution. Higher degradation efficiencies were encountered for the materials synthesized by the SG method, for instance, degradation efficiencies values of 58.61% (SG) and 46.12% (MW) were observed for AMX after 240 min of photocatalytic treatment under visible light at pH 3.5. With STR the following results removal efficiencies were obtained: 49.67% (SG) and 39.90% (MW) at pH 8. It was observed the increasing of degradation efficiencies values at longer treatment periods, i.e., after 300 min of photocatalytic treatment under visible light, AMX had a degradation efficiency value of 69.15% (MW) at pH 3.5, DCF 72.3% (MW) at pH 5, and STR 58.49% (MW) at pH 8.

The interaction of Alginic acid with three direct dyes (Direct blue 1, Direct red 81, and Direct black 22) was studied. It was found that as a result of this interaction formation of adducts after addition of calcium ion, facilitates their removal from aqueous solution. Our results suggest a relationship among physico-chemical properties of each dye and its removal efficiency. The main mechanisms involved in dye removal are electrostatic interactions, hydrogen bonding and hydrophobic interactions.

The residual effluent from the corn tortilla industry, referred to as Nejayote in Mexico, causes serious pollution problems because of its high chemical oxygen demand (COD). However, as this effluent contains valuable corn phytochemicals, such as ferulic acid and its derivatives, it also represents an opportunity to produce high-added-value biocompounds. In this work, we addressed environmental and biosynthetic approaches by applying laccase oxidative treatment in the presence of chitosan to reduce the environmental impact of the effluents from the tortilla industry. A central composite design pattern was used to understand the relationship between several variables (pH, temperature, reaction time, and enzyme quantity) and two responses (removal of ferulic acid derivatives and COD decrease). The optimum conditions for maximizing both responses were pH 6, 35 degrees C, 24 h, and 0.3025 nmoles laccase, which resulted in 70 and 78% decreases in phenolics and COD, respectively. UV-vis, fluorescence and FTIR analyses revealed enzymatic grafting of chitosan with phenolics from the effluent. Grafted chitosan presented a higher capacity to scavenge DPPH radicals (EC50 1.9 mg/mL) than neat chitosan (EC50 2.5 mg/mL) and higher viscosity values. The obtained results indicate that a process involving a single enzymatic step could be adequate to decrease the effluent COD and to generate polymers with potential applications in the food and pharmaceutical industries. (C) 2014 Elsevier Ltd. All rights reserved.

The goal of this research is to find a more effective treatment for tequila vinasses (TVs) with potential industrial application in order to comply with the Mexican environmental regulations. TVs are characterized by their high content of solids, high values of biochemical oxygen demand (BODs), chemical oxygen demand (COD), low pH and intense colour; thus, disposal of untreated TVs severely impacts the environment. Physicochemical and biological treatments, and a combination of both, were probed on the remediation of TVs. The use of alginate for the physicochemical treatment of TVs reduced BOD5 and COD values by 70.6% and 14.2%, respectively. Twenty white-rot fungi (WRF) strains were tested in TV-based solid media. Pleurotus ostreatus 7992 and Trametes trogii 8154 were selected due to their ability to grow on TV-based solid media. Ligninolytic enzymes' production was observed in liquid cultures of both fungi. Using the selected WRF for TVs' bioremediation, both COD and BOD5 were reduced by 88.7% and 89.7%, respectively. Applying sequential physicochemical and biological treatments, BOD5 and COD were reduced by 91.6% and 93.1%, respectively. Results showed that alginate and selected WRF have potential for the industrial treatment of TVs.