Recently, photocatalysis has attracted all-embracing attention as a sustainable and green approach owing to its promising applications in the deterioration of contaminants along with the transformation of solar energy into chemical energy An efficient visible-light harnessing Copper tungstate photocatalyst has hooked excellent performance because of its peculiar features, including eco-friendliness, low cost, optimum band edge potentials, as well as stability under oxidative and acidic conditions However, any review depicting the correlation between different morphologies, properties, and performance of CuWO4 is still absent Therefore, this review highlighted the energy applications of CuWO4 photocatalyst, focusing on its morphological dimensions and strategies for photocatalytic performance enhancement Various fabrication methods, such as hydrothermal, electrodeposition, spray-pyrolysis, co-precipitation, sonochemistry, and solid-state synthesis, are also discussed Controllable synthesis of distinct morphological nanostructures with the effect of parameters like temperature, pH, solvent, reaction time, and concentration of precursors has been briefly summarized Nano-structured CuWO4 was explored to show high photocatalytic activity than pristine CuWO4 Moreover, different revamp strategies, including doping of parent photocatalyst, loading of co-catalyst on photocatalyst surface, and heterojunction construction, are assumed for the efficient space charge isolation of photo charge carriers suppressing the rapid recombination of photo-generated electron-hole pairs for dynamic photocatalytic activity The applications of CuWO4, including photocatalytic water reduction for H2 generation, photodegradation of dyes and antibiotics, and photoelectrochemical water splitting, have been highlighted Finally, a brief, conclusive remark regarding present studies and unresolved challenges of nano-structured CuWO4 are put forth for future perspectives

Performance improvement strategies of CuWO4 photocatalyst for hydrogen generation and pollutant degradation

The production of the edible mushroom Agaricus bisporus occurs on a world scale, where tons are constantly produced. At the same time, this production generates a large amount of waste that needs to be adequately conditioned. Therefore, mushroom residues were used to develop activated carbon for the removal of 2,4-D—the developed adsorbent showed a microporous structure with several spaces on the surface. The FTIR analysis showed that the activated carbon has functional groups such as aromatic rings, carboxylate, hydroxyl. It was found that the optimum adsorption of the 2,4-D occurs at pH 4 and adsorbent dosage of 0.4 g L-1; The equilibrium data were better fitted to the Freundlich model. However, for calculating the thermodynamic parameters, it was considered the Langmuir equilibrium constant (KL). The value of Langmuir Qmax was 241.7 mg g-1 at 298 K. The thermodynamic behavior indicated a spontaneous and favorable, and exothermic. The magnitude of the adsorption enthalpy is in agreement with physical adsorption. System equilibrium was attained before 30 min regardless of 2,4-D concentration. The kinetic curves showed good statistical adjustment to the linear driving force (LDF) model, with capacity values close to the experimental ones (qexp = 194.6 mg g-1; qpred = 187.3 mg g-1), at 100 mg L-1 of 2,4-D. The adsorbent removed up to 70% of the simulated effluent when using the Jacui river as the sample. Regeneration studies showed that the activated carbon could be used up to 9 times without losing significant efficiency. Last, the process cost production was estimated to be 2.39 USD kg-1 of activated carbon. Therefore, it can be concluded that activated carbon developed from edible mushroom residues is a promising alternative as an adsorbent for the treatment of actual effluents containing 2,4-D herbicide.

Preparation of activated carbon from the residues of the mushroom (Agaricus bisporus) production chain for the adsorption of the 2,4-dichlorophenoxyacetic herbicide

A versatile microfluidic paper chip platform based on MIPs for rapid ratiometric sensing of dual fluorescence signals

Dichlorophenoxyacetic acid (2,4-D) is an herbicide widely used in extensive agriculture, toxic to humans and other animals, in addition to causing contamination of water resources. The 2.4-D is resistant to conventional degradation processes, in this context, heterogeneous photocatalysis is presented as a promising alternative in the degradation of this type of micropollutant. This work aims to synthesize, characterize and evaluate the catalytic activity of Fe3O4@WO3/SBA-15 in the photodegradation of (2.4-D) under ultraviolet irradiation. The nanomaterials were obtained by the co-precipitation, solvothermal and hydrothermal methods. The XRD patterns showed that the insertion of Fe3O4@WO3 in SBA-15 (5, 10 and 20 %) did not destroy the support mesoporous structure as well as indicated Fe3O4 and WO3 chrystillen phases. The core-shell morphology was confirmed by micrographs (FESEM, TEM and HRTEM) as well as the average size of the particles of WO3 = 35.8 nm and Fe3O4 = 13.3 nm. The energetic gap of nanomaterials were (WO3 = 2.6, Fe3O4 = 2.8, Fe3O4@WO3 = 1.9, Fe3O4@WO3/SBA-15 (5 %). = 2.7, Fe3O4@WO3/SBA-15 (10 %) = 1.7 and Fe3O4 @ WO3/SBA-15 (20 %) = 1.8). The Fe3O4@WO3/SBA-15 (X%) samples showed magnetic properties and photocatalict efficience for 2,4 D photodegradation under UV irradiation. The Fe3O4@WO3/SBA-15 (5 %) sample has promoted 90.73 % of degradation of the herbicede, at 240 min.

Synthesis, characterization and catalytic activity of Fe3O4@WO3/SBA-15 on photodegradation of the acid dichlorophenoxyacetic (2,4-D) under UV irradiation

Application of water treatment sludge as a low-cost and eco-friendly catalyst in the biodiesel production via fatty acids esterification: Process optimization

Titanium dioxide nanoparticles (nTiO2) were used in heterogeneous photocatalysis for remediation of herbicide Tordon 2,4-D. These nTiO2 was synthesized by the sol-gel method followed by thermal treatment at 450 °C for 2 h. The structural characterization by X-ray diffraction and Rietveld refinement confirm that the mixture of phases is 21.28 % of anatase (tetragonal) and 78.12 % of brookite (orthorhombic). All vibrational modes characteristic of anatase and brookite in the interval from 85 to 1100 cm−1 were confirmed using the Raman spectroscopy. The composition of nTiO2 was studied using the X-ray spectroscopy analysis (XPS), where TiO2 and traces of Ti2O3 were confirmed. The nTiO2 exhibit strong absorption in the region of 427 nm with direct optical bandgap (Egap) calculated equal to 2.90 eV. For all catalytic tests with nTiO2 as a catalyst there where high photocatalytic performance. Also, the total degradation for molecules of 2,4-D herbicide in aqueous solution was obtained at 45 °C for 40 min under UVc radiation. The toxicity tests with Allium cepa bulbs show that the solutions collected after the photocatalytic treatment with nTiO2 nanoparticles was similar when compared with the negative control (distilled water) results. Moreover, the positive control (Tordon 2,4-D solution) and residue after the photolysis test exhibited high toxicity, inhibiting the growth and development of bulbs and roots.

Heterogeneous photocatalysis of Tordon 2,4-D herbicide using the phase mixture of TiO2

Os catalisadores acidos normalmente empregados na sintese de biodiesel apresentam diversas desvantagens, tais como corrosao e difi culdade de reutilizacao. Assim, este trabalho teve como objetivo a sintese e caracterizacao do catalisador solido acido SO42−/TiO2/metacaulim pelo metodo de impregnacao, onde o TiO2 foi preparado pelo metodo sol-gel e diretamente suportado no metacaulim do Amazonas com posterior sulfatacao. O catalisador obtido (STMK) foi caracterizado pelas tecnicas de fl uorescencia (FRX) e espectroscopia de infravermelho (FTIRATR). A atividade catalitica do STMK foi avaliada pela esterifi cacao do acido oleico com metanol, apresentando conversao superior a 96% nas seguintes condicoes reacionais: razao molar metanol:acido 20:1, 105°C, 5% m/m de catalisador em relacao a massa do acido e 1 h de reacao. O alto potencial do STMK como catalisador para a producao de biodiesel foi demonstrado.

Uso de caulim do amazonas para a obtenção de catalisador sólido ácido (so42-/tio2/mk) com aplicação na síntese de biodiesel por esterificação

In this work were produced and characterized activated coal-based composite of oily sludge residues and synthetic iron oxide at different temperatures contaminants removal of contaminants in aqueous solution. The composites showed different compositions of coal, metallic iron and iron oxides (hematite, magnetite/maghemite and wustite) with fairly magnetic behavior. The estimated surface area of these materials by the indirect method of adsorption of methylene blue showed a decrease from the activated coal (273 m 2 g -1 ) for the composite prepared at 800 C (191 m g). The results adsorption of methylene blue, Cd 2+ and Pb 2+ by adsorbent materials in general, fitted to the Langmuir isotherm. Also, the data showed good correlation with the isotherms of Freundlich and Sips. The maximum amount absorbed for methylene blue (141.5 mg g -1 ) with activated coal, for the Cd 2+ (503.4 mg g -1 ) with composite at 600 C and for the Pb (464.4 mg g) with composite at 800 C, were probably due to the materials constitution, since the magnetic materials have a higher adsorption capacities for the Cd 2+ and Pb 2+ , while non-magnetic material (as a activated coal) showed a higher adsorption for methylene blue.

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Activated Coal-Based Composites of Oily Sludge and Iron Oxides for the Removal of Contaminants in Aqueous Solution

Neste trabalho foram produzidos e caracterizados compositos a base de carvao ativado de residuos de borra oleosa e oxido de ferro sintetico, em diferentes temperaturas visando remocao de contaminantes em meio aquoso Os compositos apresentaram composicoes variadas de carvao, ferro metalico e oxidos de ferro (hematita, magnetita/maghemita e wustita) com moderado comportamento magnetico A area superficial desses materiais, estimada pelo metodo indireto de adsorcao de azul metileno, mostrou uma diminuicao a partir do carvao ativado (273 m 2  g -1 ) para o composito preparado a 800 o C (191 m 2  g -1 ) Os dados de adsorcao do azul de metileno, Cd 2+ e Pb 2+ pelos materiais adsorventes, no geral, apresentaram tendencia para isoterma de Langmuir As de Freundlich e Sips tambem mostraram boa correlacao As quantidades maximas absorvidas de 141,5 mg g -1 de azul de metileno para carvao ativado, 503,4 mg g -1 de Cd 2+ para o composito a 600  o C e 464,4  mg g -1 de Pb 2+ para o composito a 800  o C, possivelmente estao relacionadas com a constituicao dos materiais, pois os materiais magneticos refletiram maiores capacidades de adsorcao para o Cd 2+ e Pb 2+ , enquanto que o material nao magnetico (carvao ativado) teve maior adsorcao para o azul de metileno DOI: 105935/1984-683520150131

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Francisco Alexandre F. Mariano

Papers

Heterogeneous photocatalysis of Tordon 2,4-D herbicide using the phase mixture of TiO2

Uso de caulim do amazonas para a obtenção de catalisador sólido ácido (so42-/tio2/mk) com aplicação na síntese de biodiesel por esterificação

Activated Coal-Based Composites of Oily Sludge and Iron Oxides for the Removal of Contaminants in Aqueous Solution

Compósitos à Base de Carvão Ativado de Borra Oleosa e Óxidos de Ferro para Remoção de Contaminantes em Meio Aquoso