Acid red G dye removal from aqueous solutions by porous ceramsite produced from solid wastes: Batch and fixed-bed studies

A novel porous ceramsite was made of municipal sludge, coal fly ash, and river sediment by sintering process, and the performance of batch and fixed-bed column systems containing this material in the removal of acid red G (ARG) dye from aqueous solutions was assessed in this study. The results of orthogonal test showed that sintering temperature was the most important determinant in the preparation of porous ceramsite, and it possesses developed pore structure and high specific surface area. Batch experiment results indicated that the adsorption process of ARG dye toward porous ceramsite was a spontaneous exothermic reaction, which could be better described with Freundlich–Langmuir isotherm model (R2 > 0.992) and basically followed the pseudo-first-order kinetic equation (R2 > 0.993). Column experiment results showed that when the porous ceramsite was used as packing material, its adsorption capacity was roughly improved by 3.5 times compared with that in batch system, and the breakthrough behavior was simulated well with Yoon–Nelson model, with R2 > 0.954. This study suggested that the novelty man-made porous ceramsite obtained from solid wastes might be processed as a certain cost-effective treatment material fit for the dye removal in aqueous solutions.

Retraction: Ni/Co/Ti layered double hydroxide for highly efficient photocatalytic degradation of Rhodamine B and Acid Red G: a comparative study

Retraction of ‘Ni/Co/Ti layered double hydroxide for highly efficient photocatalytic degradation of Rhodamine B and Acid Red G: a comparative study’ by Priyadarshi Roy Chowdhury and Krishna G. Bhattacharyya, Photochem. Photobiol. Sci., 2017, 16, 835–839.

A 2.5D Electrode System Constructed of Magnetic Sb–SnO2 Particles and a PbO2 Electrode and Its Electrocatalysis Application on Acid Red G Degradation

A novel electrode consisting of a Ti/PbO2 shell and Fe3O4/Sb–SnO2 particles was developed for electrochemical oxidation treatment of wastewater. Scanning electron microscope (SEM), X-ray diffraction (XRD), the current limiting method, toxicity experiments, and high-performance liquid chromatography were adopted to characterize its morphology, crystal structure, electrochemical properties, the toxicity of the wastewater, and hydroxyl radicals. Acid Red G (ARG), a typical azo dye, was additionally used to test the oxidation ability of the electrode. Results indicated that the 2.5D electrode could significantly improve the mass transfer coefficient and •OH content of the 2D electrode, thereby enhancing the decolorization, degradation, and mineralization effect of ARG, and reducing the toxicity of the wastewater. The experiments revealed that, at higher current density, lower dye concentration and higher temperature, the electrochemical oxidation of ARG favored. Under the condition of 50 mA/cm2, 25 °C, and 100 ppm, the ARG, Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) removal efficiency reached 100%, 65.89%, and 52.52%, respectively, and the energy consumption and the current efficiency were 1.06 kWh/g COD, 8.29%, and energy consumption for TOC and mineralization current efficiency were 3.81 kWh/g COD, 9.01%. Besides, the Fe3O4/Sb–SnO2 particles after electrolysis for 50 h still had remarkable stability. These results indicated that the ARG solution could be adequately removed on the 2.5D electrode, providing an effective method for wastewater treatment.

Toxicity Assessment of Biologically Degraded Product of Textile Dye Acid Red G

Azo dyes are of environmental concern due to their recalcitrant nature. Several azo dyes and their decolorized and degraded products exert toxic and mutagenic effects on the flora and fauna. The toxic properties of these azo dyes are due to nature and position of the substitution with respect to the aromatic rings and amino nitrogen atoms. Several studies have thus far been emphasized on biodegradation of azo dye pollutants, though role of their biodegraded product is rarely studied. Given a lack of this understanding, we have analyzed the effects of degraded products of a di-azo textile dye Acid Red G by newly isolated bacterial species, Pseudomonas aeruginosa PFK10 and Brevibacillus choshinensis PFK11. The genotoxicity and cytotoxicity of Acid Red G and their degraded products were tested on HeLa cell line and Human lymphocyte cell, respectively. The data of MTT assay has been shown that activity of degraded products of the Acid Red G were comparable to their parent dye. But chromosome aberration assay and sister chromatid exchange assay did not show any significant changes in chromosomes as compared to positive control mitomicine.

PREPARACIÓN DE FILTROS DE ADSORCIÓN A BASE DE ARCILLAS MODIFICADAS

PREPARACIÓN DE FILTROS DE ADSORCIÓN A BASE DE ARCILLAS MODIFICADAS PREPARATION OF FILTERS ADSORPTION-BASED MODIFIED CLAYS María del Rosario Sun Kou, José Inga, Abel Gutarra DOI: https://doi.org/10.33017/RevECIPeru2007.0005/ RESUMEN La cantidad de contaminantes textiles (colorantes, surfactantes, fenoles entre otros) se ha incrementado en los últimos años en el Perú debido al aumento en los volúmenes de exportación, La adsorción es uno de los métodos más ampliamente usados para minimizar el grado de contaminación en los efluentes industriales, esto a motivado el desarrollo de materiales abundantes y de bajo costo que puedan ser utilizados como adsorbentes. Para este trabajo se ha empleado bentonitas peruanas, sódicas (LI-01 y LI-03) y cálcicas (HU-01 y HU-02), modificadas por termoactivación con HCl y H2SO4. Estos materiales fueron probados en la adsorción de diferentes colorantes: Rojo 80, Rhodamine B, rojo ácido G, azul de metileno. Comparada con la arcilla natural, la muestra termoactivada LI-03 incrementó su poder de adsorción en 13 veces, mientras la muestra HU-01 el incremento fue de 11 veces. El proceso de adsorción se produjo a pH entre 3 y 4 y cuando fue adicionado electrolitos a la solución coloreada.El mejor método encontrado para la preparación de los filtros de adsorción a base de arcillas termoactivadas fue el de la esponja polimérica con tratamientos térmicos entre 500 a 980°C. Los filtros preparados adsorbieron el 100% del colorante Rhodamine B y del azul de metileno. La adsorción se logró en menor grado con los colorantes rojo 80 y rojo ácido G. Palabras claves: adsorción, filtros de adsorción, arcillas termoactivadas, colorantes textiles. ABSTRACT During the last years in Perú the amount of textile contamination (dyes, surfactants, phenols among others) has increased due to the increase in export volumes.Adsorption is one of the methods most often used to minimize the grade of contamination in industrial effluents, and it has encouraged the development of abundant materials wich are low cost and so they could be used as adsorbents. For this work has been used peruvian bentonites, sodium (LI-01 and LI-03) and calcium (HU-01 and HU-02), modified by thermo-activation with HCl and H2SO4. These materials were tested in the adsorption of several dyes: Red 80, Rhodamine B, Acid Red G, methylene blue. A sample of thermo-activated LI-03 increased its power of adsorption thirteen times compared with the natural clays, on the other hand in the case of HU-01 increase was eleven times. The adsorption process is produced in pH range of 3 - 4 when electrolytes were added into dye solution.The best method found for the preparation of filters of adsorption from thermo-activated clays was the polymer sponge with thermic treatment in the range of 500 - 980ºC. Prepared filters adsorbed 100% of dyes: Rhodamine B and Methylene Blue. The adsorption got in low degree with Red dye 80 and Acid Red G. Keywords: Adsorption, filters of adsorption, thermo-activated clays, textile dyes.

Synergetic effects of graphene–CoPc/silk fibroin three-dimensional porous composites as catalysts for acid red G degradation

The disposal of dye wastewater is one of the hotspots of scientific research, and graphene–CoTAPc–SF composites exhibit more effective catalytic abilities.