Azo Dye Acid Research Articles

Flower-like MoS2/BiFeO3 doped silver orthophosphate catalyst for visible-light assisted treatment of refractory organic pollutants

The development of MoS2/BiFeO3 embedded silver orthophosphate ternary composite for the excellent photocatalytic abatement of refractory pollutants was established. The fabrication of a confounded heterojunction photocatalyst composite for the enhanced treatment of various dyes, pesticides and antibiotic drugs with extra stability and observable reproducibility are possible. The acid dye methyl orange, basic dyes such as methylene blue, rhodamine B and an azo dye acid red 18 were successfully degraded with above 90% degradation efficiency within a very short time period. These results highlighted that the degradation efficiency of the developed composite was 8 times higher than the pure Ag3PO4 catalyst. Also, the hazardous herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) was degraded and mineralized within 180 min, the most toxic insecticide acephate was degraded within 60 min and the antibiotic tetracycline was removed in 120 min with accountable mineralization. All the pesticides and antibiotic formed less toxic degraded products and the products were corroborated with high resolution mass spectrum (HRMS). The radical scavenger experiment reveals that the active species for photodegradation study was photogenerated holes. These are produced by the rapid transfer of electrons through Ag3PO4 due to its low recombination tendency. In short, the development of Ag3PO4 based ternary composite for the better visible light assisted catalytic degradation of refractory pollutants such as dyes, pesticides and pharmaceutical drugs were carried out with excellent efficiency.

Haematological Parameters and Histopathological Alterations in the Gills of Fish, Catla catla Exposed to Azo Dye Acid Red -97

Haematological and histopathological parameters have been recognized as valuable tools for monitoring fish health. This study was conducted to evaluate the chronic toxicity of Acid Red 97 textile dyes on haematological and histopathological alterations using Catla catla as animal model. Fish were exposed to two Sublethal concentrations (1/100th and 1/50th of LC50 = 85mg/l) 0.85 mg/l and 1.7 mg/l of AR 97 for a period of (10, 20 and 30) days. Haematological parameters were observed that with increase of exposure time, total erythrocyte (RBC), haemoglobin (Hb), and packed cell volume (PCV) values decreased but leucocytes (WBC), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) values increased. It is believed that observed depression in packed cell volume and haemoglobin values coupled with decreased and deformed erythrocytes are obvious signs of anemia. Resulted changes in erythrocytes and leukocytes after exposing to AR 97 are due to malfunction in hemopoiesis and decrease in non-specific immune system. Histopathological changes observed in the gills of Catla catla were swelling, aneurysm, fusion of lamellae, oedema in primary lamellae, shortened and severe erosions of secondary lamella and lifting epithelial layer and high mucus secretion. Hence, it was concluded that azo dye AR 97 has potential to cause toxicity in fish.

Co-enhanced activated sludge system by static magnetic field and two halotolerant yeasts for azo dye treatment.

The effect of static magnetic field (SMF) on azo dye Acid Red B (ARB) decolorization by the co-culture of activated sludge (AS) and two halotolerant yeasts Candida tropicalis A1 and Pichia occidentalis A2 was investigated. Microbial community structure of the co-cultures before and after treatment with SMFs of different intensity was analyzed through high-throughput sequencing and quantitative real-time polymerase chain reaction. The results showed that ARB decolorization efficiency by the defined co-culture was 1.25-fold to 1.51-fold elevated by 24.6-305.0mT SMF. The best ARB decolorization and chemical oxygen demand (COD) removal performances by the co-culture were both achieved with 95.0mT SMF. By contrast, biomass multiplication and sedimentation property of AS systems were not significantly influenced by SMF. Higher activities of intracellular key enzymes were determined (with 95.0mT SMF) as responsible for better decolorization and COD removal performances. Bacteria belonging to Prolixibacter, Corynebacterium, Pelagibacterium, Demequina, and Sphingobacterium which might be responsible for azo dye decolorization and aromatic compounds biodegradation were significantly enriched only in presence of SMF. Fungal genera Candida and Pichia were also significantly enriched by 41.4-305.0mT SMF, which might be responsible for higher treatment efficiency. PRACTITIONER POINTS: Dye degradation was enhanced by combination of static magnetic field and yeasts. Improvement of enzyme activity was responsible for better treatment performance. Putative azo-degrading-related bacteria and fungi were selectively enriched. High relative abundance of Candida and Pichia ensured high decolorization effects. Potentially effective improvement of bioprocesses for treating hypersaline wastewater.

A facile synthesis and study of photocatalytic properties of magnetic CaFe2O4-CeO2 nanocomposites applicable for separation of toxic azo dyes

At the first step calcium ferrite nanostructures were synthesized via a facile precipitation method in the presence of green and compatible capping agent such as starch, poly vinyl pyrrolidone and glucose in solvent of water. Then cerium oxide nanoparticles and CaFe2O4-CeO2 nanocomposites was made by a fast chemical procedure. The effect of temperature in nanoparticles and nanocomposites concentration and precipitating agent on the morphology and particle size of the products was investigated. The prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy. Also the crystalline size of nanoparticles was calculated by Debye-Scherrer formula. Vibrating sample magnetometer (VSM) shows the ferromagnetic property of the ferrite nanostructures. The photocatalytic behaviour of CaFe2O4-CeO2 nanocomposites was evaluated using the degradation of three azo dyes (acid black, acid violet and acid blue) under ultraviolet light irradiation. The results introduce a nanocomposite with applicable magnetic and photocatalytic performance.

Quaternary‐Ammonium‐Based Gels with Varied Alkyl Chains for the Efficient Removal of Toxic Acid Orange 7

AbstractWe report the design and synthesis of thiol‐norbornene based ingenious gels with pendent quaternary ammonium substituents on the norbornene backbone that are conducive to remove toxic anionic azo dye acid orange 7 (AO7) from wastewater. Three different alkyl side chains on the dangling quaternary ammonium moiety were chosen prudently and their performance towards removal of azo dye was scrutinised. The characterisation of all the precursor monomers and the ensuing gels were accomplished by 1H, 13C NMR and Mass spectrometry. The influence of extent of crosslinking on the solvent uptake ability was investigated and the swelling nature of the gels were correlated with the solubility parameter of different solvents. The surface morphology of the gels as visualised by FE‐SEM analysis, revealed macropores in the range 4–12 μm. The relationship between the composition of quaternary ammonium moiety on the gels and their viscoelastic properties was realised. The dye removal kinetics as observed from UV‐Vis spectra were best correlated with the pseudo‐second‐order model and the adsorption isotherm of dye removal process was best fitted with the Langmuir isotherm model with high correlation coefficient. The material was found to be fairly recyclable up to 10th cycles with loss of only 8% efficiency. To the best of our knowledge, this is the first ever report on the removal of anionic dye based on thiol‐norbornene photo crosslinked network. We believe that this design and composition‐property relationship will enthuse the researchers to develop efficient chemical adsorbents based on environmentally benign systems.

Continuous treatment of an azo dye based on a combined ZVI/photo-Fenton setup. Process modelling by response surface methodology

The performance of a continuous system that sequentially couples a column filled with zero-valent iron with a photo-Fenton reactor was evaluated under mild acidic conditions. Studies were conducted to evaluate the better coupling strategy between each treatment module and to analyze the effects of several operational parameters on the system behaviour. The azo dye Acid Black 1 was chosen as model pollutant. Decolourization degrees and decreases of TOC values were used for the evaluation of the treatment performance under different conditions; whereas steady state concentrations of Fe(II), Fe(III) and H2O2 together with spectral features in the UV–vis region were analysed to elucidate mechanistic issues. The response surface methodology approach based on a central composite design was used to evaluate and model the effects of key factors on the decolourization degrees.Results show that the spatial separation between the ZVI and H2O2 may lead to substantial improvements of treatment efficiencies provided that configurations involving recirculation loops are avoided. Besides, a strict and continuous pH control during the oxidative stage is critical for obtaining a stable operation and acceptable decolourization efficiencies through the coupled system. The simple parameters developed from UV–vis spectra allowed monitoring the extent of reductive and oxidative transformation pathways. In addition, the statistical analysis shows that reactor pH and hydraulic residence time are the key factors influencing the system response, whereas initial pH and added oxidant concentration are much less significant. The conclusions drawn are relevant from a technological viewpoint since allow a rational design of cost-effective treatments.

An accomplished procedure of horseradish peroxidase immobilization for removal of acid yellow 11 in aqueous solutions.

Horseradish peroxidase (HRP) characteristics were improved by two techniques, Na-alginate entrapment and glutaraldehyde crosslinking prior to alginate entrapment, in order to enhance the stability, functionality and removal of dyes in waste water. Free, entrapped and crosslinked-entrapped enzymes were compared by activity assays, which indicated the optimum temperature is 25 °C and pH 4.0-5.0. Kinetics results showed that alginate entrapment and crosslinking prior to entrapment increased Vmax and did not cause any significant decrease in Km. The thermal resistance of the free enzyme was short-term, zero residual activity after 250 min, while the immobilized enzymes preserved more than 50% of their activity for 5 h at 60 °C. Immobilized HRP was resistant to methanol, ethanol, DMSO and THF. The storage stability of free HRP ended in 35 days whereas entrapped and crosslinked-entrapped HRPs had 87 and 92% residual activity at the 60th day, respectively. HRP was used in the decolorization of azo dye Acid yellow 11 and total decolorization (>99%) was obtained using crosslinked-entrapped HRP. Reusability studies presented the improvement that crosslinked-entrapped HRP reached 74% decolorization after 10 batches. The results demonstrated that the novel immobilized HRP can be used as an effective catalyst for dye degradation of industrial waste effluents.

Phytoremediation of azo dye methyl red by macroalgae Chara vulgaris L.: kinetic and equilibrium studies.

Phytoremediation is an innovative, eco-friendly, and solar-driven technique, which becomes a well-known alternative solution for remediation of hazardous dyes from wastewater. In present research work, potential of a submerged fresh water macroalgae Chara vulgaris L. (C. vulgaris) examined for removal of acidic azo dye methyl red (MR) in its solution form. A series of experiments were done with C. vulgaris to predict the effects of different parameters viz. contact time, initial dye concentration, amount of macroalgae, and pH. The increase in initial dye concentration directly impacts on the potential of macroalgae. The decolorization percentage declined with increase in initial dye concentration. The equilibrium condition was found to achieve after contact time of approximately 48h. The decolorization of MR dye was found to be favorable at pH5. The macroalgae was successfully utilized repeatedly with MR for eight cycles in batch experiments. The kinetics of phytoremediation of MR dye was studied with help of pseudo-first-order, pseudo-second-order, and Elovich kinetic models and the results were well suited to pseudo-second-order kinetic model with the correlation value R2 ≥ 0.99. In addition, the experimental data was also assessed by using Langmuir and Freundlich adsorption equilibrium isotherms. The results of phytoremediation data was found to be in favor of Freundlich equilibrium isotherm which having the correlation value R2 ≥ 0.977. The intraparticle diffusion model also studied to interpret the macroalgae phytoremediation mechanism for phytoremediation of MR. The surface interactions of C. vulgaris were investigated before and after the removal of dye with Fourier transform-infrared spectroscopy (FTIR) technique. On the basis of these studies, a hypothetical mechanism has also been proposed to depict the phytoremediation of acidic azo dye by C. vulgaris.

Design of magnetically assembled electrode (MAE) with Ti/PbO2 and heterogeneous auxiliary electrodes (AEs): The functionality of AEs for efficient electrochemical oxidation

Heterogeneous auxiliary electrodes (AEs, Fe3O4/Sb-SnO2 or Fe3O4/Pb3O4 granules) with different amount were loaded on foil Ti/PbO2 (main electrode, ME) and thereby formed series of so-called magnetically assembled electrode (MAE) for more efficient, flexible and versatile electrochemical oxidation (EO) treatment of organic wastewater. Diverse material characterizations and electrochemical characterizations were performed to investigate the nature of the AEs and the effects of AEs type and assembling amount on the electrochemical behaviors of the MAE, respectively. Azo dye Acid red G (ARG) and lignosulphonate (lignin) were selected as the target pollutants to examine the effects of AEs type and assembling amount on the EO performance of MAE. Results show that both two types of AEs could increase the electrochemical roughness and the active sites, but with different optimum amount. Compared with 2D Ti/PbO2, a series of MAEs exhibited about 18%-30% higher efficiency in ARG degradation, among which the MAE with higher Fe3O4/Pb3O4 AEs amount had better performance. However, in breaking lignin macromolecule structure into smaller molecules, the MAE with higher Fe3O4/Sb-SnO2 AEs amount was better. The different synergisms between the two heterogeneous AEs and the ME in EO were proposed, and the relationship of the chemical composition, structure and electrocatalytic activity of the MAEs were further revealed. Finally, stability experiment results showed that the MAEs were safe and reliable.

Adsorption behavior and mechanism of acid orange 7 and methylene blue on self-assembled three-dimensional MgAl layered double hydroxide: Experimental and DFT investigation

The removal of toxic ionic dyes is an urgent issue in the water pollution control field. Herein, the self-assembled three-dimensional MgAl layered double hydroxide (3D-MA-LDH) have been synthesized via the soft-template synthesis employing sodium dodecyl sulfate (SDS) as soft template and can be successfully applied in the anionic azo dye Acid Orange 7 (AO7) and cationic heteroaromatic compound methylene blue (MB) removal. The maximum removal capacities were 485.6 and 58.3 mg·g−1 for AO7 and MB, respectively. The removal behavior for AO7 and MB fitted the Langmuir and Freundlich model, respectively, and revealed a diffusion process contained chemical adsorption. X-ray diffraction, Fourier transform spectroscopy, and X-ray photoelectron spectroscopy demonstrated that anion exchange dominated the AO7 removal, while MB was adsorbed via hydrophobic interaction between MB and DS. Density functional theory further confirmed the interaction, wherein the bonding distance was 1.622 Å between AO7 and 3D-MA-LDH’s layer. MB showed strong affinity toward DS with no dependence of bond connection to be stably anchored on the 3D-MA-LDH. In addition, the recyclability experiments exibited that 3D-MA-LDH could be stably reused for at least five times. This work provided a new approach for cleaning ionic dyes and broadened the application field of 3D- LDHs.

Degradation of azo dye Acid Red 14 (AR14) from aqueous solution using H2 O2 /nZVI and S2 O8 2- /nZVI processes in the presence of UV irradiation.

Azo dyes are mostly toxic and carcinogenic and cause harm to humans and the environment. This study was conducted to investigate the degradation of azo dye acid red 14 (AR14) from aqueous solution using hydrogen peroxide (H2 O2) /nano zerovalent iron (nZVI) and persulfate (S2 O8 2- )/nZVI processes in the presence of ultraviolet (UV) irradiation. This experimental study was carried out in a laboratory-scale batch photoreactor with a useful volume of 1 L. The nZVI was synthesized by the sodium borohydride (NaBH4 ) reduction method. In these processes, the effects of parameters including initial pH, H2 O2 concentration, S2 O8 2- concentration, nZVI dose, concentration of AR14 dye, and reaction time were studied. The results showed that decolorization increased by increasing the nZVI dosage, H2 O2 and S2 O4 2- concentrations, and reaction time, or decreasing dye concentration and pH. However, a too high oxidant concentration (H2 O2 and S2 O4 2- ) could inhibit the degradation. The experimental conditions for degradation of AR14 by UV/S2 O8 2- /nZVI and UV/H2 O2 /nZVI processes were as follows: [H2 O2 ]=10mM, [S2 O8 2- ]=8mM, AB14 dye=100mg/L, pH=3, and nZVI dose=0.05g. Under these conditions, the highest removal efficiencies of AR14, chemical oxygen demand (COD), and total organic carbon (TOC) for the UV/S2 O8 2- /nZVI process were 93.94%, 86.5%, and 81.6%, respectively, while these values were 89.3%, 79.57%, and 72.9% for the UV/H2 O2 /nZVI, respectively. Also, the average oxidation state (AOS) was decreased from 2.93 to 2.14 in the effluent of the UV/S2 O8 2- /nZVI process and from 2.93 to 2.2 for the UV/H2 O2 /nZVI process. The results showed that the ratio of biochemical oxygen demand (BOD5 ) to COD in the effluents of the UV/S2 O8 2 /nZVI and UV/H2 O2 /nZVI processes after 90min was 0.63 and 0.74, respectively. These findings suggest biodegradability improvement. PRACTITIONER POINTS: Photocatalytic degradation of azo dye Acid Red 14 (AR14) was achieved using H2 O2 /nZVI and S2 O8 2- /nZVI processes in the presence of UV irradiation. Effects of operating parameters on photocatalytic degradation AR14 dye were evaluated in the UV/H2 O2 /nZVI and UV/S2 O8 2- /nZVI processes. Biodegradability and mineralization studies of AR14 dye photocatalytic degradation were performed for the UV/H2 O2 /nZVI and UV/S2 O8 2- /nZVI processes.

Degradation of AO7 with Magnetic Fe3O4-CuO Heterogeneous Catalyzed Sodium Percarbonate System

Magnetically recyclable Fe3O4-CuO was synthesized by a one-step hydrothermal method and characterized by scanning electron microscopy coupled with energy dispersive spectrometer (SEM-EDS) and X-ray diffraction (XRD). The degradation of azo dye acid orange 7 (AO7) by percarbonate (SPC) activated with Fe3O4-CuO was studied. The effects of Fe3O4-CuO catalyst loading, SPC concentration, pH value, and common chloride ions on AO7 degradation in the Fe3O4-CuO/SPC system were evaluated. The main reaction mechanism of AO7 degradation was analyzed. The results show that Fe3O4-CuO could effectively activate SPC to degrade AO7 and the reaction was accelerated with the increase of Fe3O4-CuO dosage. The increase of SPC dosage was favorable for the degradation of AO7, but excessive SPC dosage inhibited the degradation of AO7. Common ions (e.g., Cl-) in dye wastewater could promote the degradation of AO7, and the degradation rate increased with increasing concentration of Cl-. The reaction mainly occurred on the surface of the catalyst, and·OH was identified as the main active species for the degradation of AO7. The catalyst Fe3O4-CuO showed excellent stability owing to the high catalytic activity remaining after 4 cycles of repeated use. The Fe3O4-CuO/SPC system achieved a high mineralization rate in the process of decolorization of AO7.

Synthesis, Characterization, and Dyeing Performance of UV Protective Mono Azo Acid Dyes Based on 4-Hydroxybenzophenone

A key element in reducing human UV exposure is making proper UV protective goods with good ultraviolet protection factor (UPF) protection. The current research is focused on the synthesis of UV-protective functional dyes containing benzophenone-based UV absorbers and its application on wool and silk fabrics. Novel mono azo acid dyes were synthesized by the coupling of diazonium salt solutions of different aromatic amines with 4-hydroxybenzophenone, and these were applied on wool and silk. The fabrics dyed with the synthesized dyes showed less than 5% UVA and UVB transmission, indicating good protection against UV radiation. Dyed fabric also gave good to excellent washing, rubbing, and light fastness, and UV protection properties, even after ten washing cycles.

New Dyes with Antimicrobial Properties

Issues with the application of new acidic azo-dyes to the dyeing and antimicrobial finishing of wool fabric are discussed. The dyes impart excellent operating properties to the textiles and allow hazardous environmental impacts to be reduced.

Novel quantification of formation trend and reaction efficiency of hydroxyl radicals for investigating photocatalytic mechanism of Fe-doped TiO2 during UV and visible light-induced degradation of acid orange 7

A detailed mechanistic investigation of the hydroxyl radical (•OH) formation and organic pollutant degradation over transition metal-doped and undoped TiO2 photocatalysts was performed by the quantitative measurement of •OH and the identification of intermediate products under various experimental conditions. The Fe-doped TiO2 as a typical subject was prepared, characterized and used to degrade an azo dye Acid Orange 7 (AO7). It is indicated that the enhanced photocatalytic activity of Fe-doped TiO2 for AO7 degradation was attributed to the increase in surface area, the facilitated charge transfer via Fe-dopant, and a red shift of absorbable wavelength, maintaining a great formation of •OH under visible irradiation. The oxidation of H2O by holes was estimated as the major pathway of •OH formation rather than the reduction of dissolved O2 by electrons, and their formation trends reached to approximately 75% and 25%, respectively. Meanwhile the synergistic effect of Fe-dopant produced nearly 10% of extra •OH by visible light photoactivation. The intermediate products and pathways of AO7 degradation varied greatly with different photocatalysts and conditions of the process, involving several reaction mechanisms such as the azo bond cleaving, naphthalene oxidation, desulfonation, and hydroxylated products generation. Through the quantification of •OH-reacted efficiency we proposed, a stoichiometry of •OH affecting overall reaction mechanisms in the TiO2-assisted photodegradation of AO7 was further established. This study can provide new insights on how to better clarify the variation regularity of organic pollutant degradation from different treatments of the •OH-based advanced oxidation processes.

Soybean Peroxidase Catalyzed Decoloration of Acid Azo Dyes.

Background.Some industrial manufacturing processes generate and release dyes as water pollutants, many of which are toxic and hazardous materials. There is a need for milder, greener methods for dye treatment.Objectives.The objective of the present study was to investigate and optimize azo dye decoloration by a crude soybean peroxidase (SBP), based on two dyes that have widespread industrial use, but that differ greatly in structural complexity, Acid Black 2 and Acid Orange 7, and to investigate the effects of specific parameters on the removal process.Methods.Batch reactors were used to remove 95% of the dyes' color and to produce substantial precipitates.Results.The optimum pH for enzymatic decoloration of Acid Black 2 was in the acidic region, pH 4.4, and that of Acid Orange 7 occurred under neutral conditions, pH 6.9. The minimum enzyme activity needed for sufficient removal was 1.2 U/mL for both dyes at 0.5 mM. The minimum molar hydrogen peroxide/substrate ratio was 3 for Acid Orange 7 and 2.5 for Acid Black 2 to achieve approximately 95% removal. First-order fitting of progress curve data collected under the respective optimum conditions gave half-lives of 23.9 and 28.9 minutes for Acid Orange 7 and Acid Black 2, respectively.Conclusions.The feasibility of SBP-catalyzed treatment of industrial dyes Acid Black 2 and/or Acid Orange 7, or dyes that resemble them, as they might occur in industrial effluents, was successfully demonstrated.Competing Interests.The authors declare no competing financial interests

Application of Photo-Fenton System (UV/ H2O2/ Fe2+) for Efficient Decolorization of Azo-Dye Acid Yellow 17 in Aqueous Solution

Herein we report, the robustness of UV/H2O2/Fe2+ system for efficient decolorization of azo-dye Acid Yellow (AY17) solution. It has been found that 88% AY17 decolorized by UV/H2O2/Fe2+ system in 25 minutes under the following optimized conditions; [dye] = 0.14 mM, [H2O2] =1.0 mM, [Fe2+ ] = 0.09 mM, stirring velocity =100 rpm, and pH = 3.0. The decolorization of AY17 by UV/H2O2/Fe2+ system exhibits second-order reaction kinetics. Thermodynamic parameters, activation enthalpy, rH*, (13.76 kJ/mol1), and entropy rS*, (0.034686 J/K) of the dye decolorization were also determined. It was ascertained that electrolytes such as HCO3−, CO32−, Cl−, and SO42− decrease the decolorization efficiency by scavenging the hydroxyl radical generation in the dye solution. Finally, the AY17 decolorization in the tape water sample by UV/H2O2/Fe2+ system was also examined.

A modular functionalized anode for efficient electrochemical oxidation of wastewater: Inseparable synergy between OER anode and its magnetic auxiliary electrodes

Oxygen evolution reaction (OER) anodes, (e.g., IrO2) are well-known inefficient catalysts for electrochemical oxidation (EO) of refractory organics in wastewater due to the high energy consumption via OER. However, in this study this kind of anode participated in a very effective EO process via a specific modular anode architecture. Traces of magnetic Fe3O4/Sb-SnO2 particles as auxiliary electrodes (AEs) were attracted on the surface of the two-dimensional (2D) Ti/IrO2-Ta2O5 by a NdFeB magnet, and thereby constituted a new magnetically assembled electrode (MAE). MAE could be renewed by recycling its AEs. The electrochemical properties as well as the EO performances of the MAE could be regulated by adjusting the loading amount of AEs. Results showed that even a small amount of AEs could increase surface roughness and offer massive effective active sites. When removing color of azo dye Acid Red G, the optimal MAE exhibited ∼1100 % and ∼500 % higher efficiencies than 2D Ti/IrO2-Ta2O5 and 2D Ti/Sb-SnO2, respectively. The superiority of the MAE was also applicable in degrading phenol. The synergy between Ti/IrO2-Ta2O5 and magnetic Sb-SnO2 particles was therefore discussed.

Synergistic photocatalytic performance of chemically modified amino phthalocyanine-GPTMS/TiO2 for the degradation of Acid Black 1

A novel functional material, Zinc (II) tetra-[α-(p-amino)benzyloxyl]phthalocyanine (ZnPc) upon covalent integration with glycidoxypropyltrimethoxy silane modified TiO2 (GPTMS/TiO2) is prepared here for the first time in order to improve the visible photocatalytic activity of TiO2. The photocatalytic property of obtained ZnPc-GPTMS/TiO2 hybrid was investigated by carrying out the photodegradation of di-anionic azo dye Acid Black 1 (AB1) in aqueous solution under visible light irradiation. The results revealed that the ZnPc-GPTMS/TiO2 hybrid photocatalyst greatly enhanced the photodegradation efficiency compared to that of the pure TiO2. Particularly, 0.2 wt% ZnPc-GPTMS/TiO2 photocatalyst showed the highest photocatalytic activity with a degradation ratio of 95.4% of AB 1 after 120 min irradiation. The synergistic effect between ZnPc and TiO2 was responsible for the enhanced photocatalytic activity of the ZnPc-GPTMS/TiO2 hybrid, due to the efficient charge separation with electron injection from ZnPc to TiO2. The photocatalytic mechanism was proposed preliminarily.

Effect of microwave on the synthesis of polyacrylamide-g-chitosan gel for azo dye removal

Effective dye removal is of crucial importance for the well-being of the environment and human health, and hydrogels are top-players for this goal. In this work, hydrogels of polyacrylamide grafted onto chitosan, cross-linked with N,N′-methylenebisacrylamide, were synthesized by conventional (CM) and microwave-assisted methods (MWM). The products were characterized by Fourier transform infrared spectroscopy, elemental analysis, scanning electron microscopy and swelling capacity. The developed hydrogels were evaluated as an adsorbent for the azo dye Acid Blue 113. MWM provided higher yield of the product with reduced reaction time when compared to the CM. The dye removal efficiency by MWM was slightly lower than that observed by CM, but MWM showed a much higher maximum adsorption capacity than the conventional one. The adsorption behavior of conventional and MW hydrogels followed the Langmuir and Freundlich models, respectively. The MW hydrogel presented the best characteristics to be used as an adsorbent of the AB 113 dye.