MO Dye Research Articles

Plant-based synthesis of cerium oxide nanoparticles using Rheum turkestanicum extract and evaluation of their cytotoxicity and photocatalytic properties

ABSTRACT Bio-synthesis of cerium (IV) oxide nanoparticles (CeO2-NPs) has been performed through a sol-gel method that involved the utilization of Rheum Turkestanicum plant extract as the stabilizing agent. The obtained nanoparticles have been identified throughout FT-IR, UV-Vis, XRD, FESEM/EDX/PSA, and TGA/DTA techniques. The XRD pattern has been presented the cubic fluorite structure of CeO2-NPs, which had indicated the particle size about 30 nm. The UV-Vis spectrum of nanoparticles has presented a strong adsorption band. The FESEM/PSA images have exhibited the spherical shape of CeO2-NPs. Furthermore, the photocatalytic activity of CeO2-NPs has been investigated by performing the decolorization of MB, RhB, and MO dyes under UVA light, which are associated with sewage water pollutants. The results of MTT assay has reported that the cytotoxicity effect of CeO2-NPs on PC12 cell lines had not been dependent on concentration, as well as an indication of the lack of any significant toxicity by the nanoparticles on cancer cells.

Fabrication of SiO2 modified biobased hydrolyzed hollow polymer particles and their applications as a removal of methyl orange dye and bisphenol-A

A special type of SiO2 grafted biobased hollow polymeric particles was fabricated from biomass trans-anethole (ANE) monomers. The SiO2 NPs were prepared through Stober method and then modified with APTES to generate amino functional groups. The (ANE) monomer and maleic anhydride (MAH) were copolymerized through precipitation polymerization to obtain hollow polymer particles, which were then functionalized with carboxyl groups via the hydrolyzation process. Finally, the biobased hydrolyzed hollow particles (BHHPs) were grafted with the amino-modified SiO2 NPs to obtain SiO2-BHHPs. The SiO2-BHHPs were investigated through SEM, TEM, FT-IR, EDX and XPS techniques and used as a bioadsorbent. The maximum adsorption capacity toward methyl orange dye (MO) and bisphenol-A (BPA) reached up to 701 and 411 mg/g, with pH = 2 respectively. The adsorption isotherm and kinetic results indicated that the MO dye and BPA adsorption was best fitted with Langmuir and pseudo-second order models. Meanwhile, the adsorption ability of the prepared particles toward MO dye was checked with the different pH range from 2 to 12. The regeneration performance revealed that the SiO2-BHHPs can be easily recycled and reused. At last, the SiO2-BHHPs based materials may find significant applications as multifunctional adsorbents and can be used further for the separation of pollutants from wastewater.

Adsorption, kinetics and thermodynamics studies of methyl orange dye sequestration through chitosan composites films

Different films comprising pure chitosan (CS) and chitosan coated sodium zeolites composites films designated as CSZ1, CSZ2, CSZ3 and CSZ4 respectively are presented here for the sequestration of MO dye. The as-synthesized films were characterized by using FSESM, XPS XRD, and TGA analysis. The sequestration of methyl orange dye (MO) was studied under various adsorption parameters i.e. pH effect, reaction temperature, catalytic dosage, interaction period, and original dye concentration in batch experiments. The adsorption power of MO dye sequestration in the presence of CSZ3 was 287 mg g−1 higher than the fine CS (201 mg g−1), and lowest for CSZ4 (173 mg g−1). The experimental data is fitted in the pseudo-second order of chemical kinetics. The Freundlich and Langmuir adsorption models were used on behalf of the analysis of experimental data that revealed multilayered adsorption of MO dye. Kinetics, equilibrium and thermodynamic process were discussed in detailed, suggesting the endothermic and spontaneous process of the adsorption of MO dye on the exterior of films. The present work is general for the MO adsorption, however, it can be applied on large scale applications and can be easily adjustable in the water purification assemblies.

Polyaniline supported CdS/CeO2/Ag3PO4 nanocomposite: An “A-B” type tandem n-n heterojunctions with enhanced photocatalytic activity

In the present work, ternary composites of the form CdS/CeO2/Ag3PO4 with CdS:CeO2/Ag3PO4 molar ratios of (1:1, 2:1, 3:1 and 4:1) were synthesized by co-precipitation method. Polyaniline supported CdS/CeO2/Ag3PO4 nanocomposite was also synthesized by “in situ” chemical oxidative method. Physicochemical properties of the photocatalyst materials were determined using XRD, BET, SEM-EDX, TEM, UV/Vis, FTIR and PL techniques. Photocatalytic activities of the ternary CdS/CeO2/Ag3PO4 (1:1, 2:1, 3:1 and 4:1 molar ratios) nanocomposites were found to be higher than their single and binary counterparts. The effects of different operational parameters such as pH, initial dye concentration, photocatalyst load and scavengers in MeO dye degradation study confirmed the following optimum values: pH 4, initial dye concentration 10 ppm and photocatalyst load 0.15 g/L. The effects of different scavengers suggest that •O2- and •OH scavengers play major roles in the degradation of MeO. The supported photocatalyst exhibited a relatively higher efficiency (93.4%) on the photodegradation of MeO dye. In addition, it showed fairly well photocatalytic activity (70.7%), for the textile effluent collected from one of the local textile industries. Furthermore, the reusability of the supported photocatalyst was tested. About 80% of the catalyst efficiency was maintained after four successive runs exhibiting the potential application of this novel composite for degradation of MO dye from aquatics system.

PMO synthesized and functionalized by p-phenylenediamine as new nanofiller in PES-nanofiltration membrane matrix for efficient treatment of organic dye, heavy metal, and salts from wastewater

Highly ordered periodic mesoporous organosilica (PMO) with large-pores (9.3 nm) synthesized using novel and cost-effective route. The synthesized PMO was then functionalized by p-phenylenediamine (PPD) and incorporated in polyethersulfone (PES) nanofiltration membrane‌ with various dosage using phase inversion method. The prepared membranes were characterized with FT-IR/ATR, FE-SEM and EDX techniques. The overall porosity, the mean of pore radius, water contact angle, fouling, permeation, and rejection were computed. As a result, the hydrophilicity and the pure water flux of membranes were significantly enhanced after modification with PMO-PPD due to its high hydrophilic nature as nanofiller. Ultimately, the modified membrane with 0.25 wt% of PPD was found the ideal membrane with water contact angle of 54.2%, pure water flux of 33.7 L/m2 h, porosity of 74.1%, and mean pore radius of 4.96 nm. This membrane showed the maximum increase in water flux and superlative anti-fouling growth when compared to the other studied membranes. Moreover, among modified membranes with various quantity of PPD, the performance of the PES-PMO-PPD 0.25 wt% was the best for rejection of MO dye (96.7%), Pb(II) (93.1%), Na2SO4 (73.0%), MgSO4 (41.6%), and NaCl (33.7%).

Synthesis of 3D-MoS2 nanoflowers with tunable surface area for the application in photocatalysis and SERS based sensing

Nanostructured two-dimensional transition metal dichalcogenides (2D-TMDCs) have been attracting great attention in the field of environmental remediation and sensing due to their high surface area and layer dependent optical and structural properties. Surface area dependent performance of MoS2 nanostructures is one of the important aspects which need to be explored for various environmental applications. In this work, MoS2 nanoflowers with tunable surface area (5–20 m2/g) were prepared by the facile hydrothermal method and their surface area dependent SERS and photodegradation activity were explored. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) studies assure the growth of MoS2 nanoflowers by the assembly of 2D-MoS2 nanosheets. MoS2 nanoflowers exhibit excellent sunlight-induced photocatalytic activity towards the degradation of methylene blue, methyl orange, rhodamine 6G and oxytetracycline hydrochloride molecules. We report that a very low amount (0.025 mg) of MoS2 nanoflowers (20 m2/g) can tremendously decompose 10 μM of MB, MO and R6G dye molecules in just 12 min, 30 min and 45 min respectively and 0.5 mg/10 mL OTC-HCl molecule in 60 min under sunlight which has not been reported yet. MoS2 nanoflowers based substrates show the remarkable SERS based detection towards the rhodamine B (RhB) molecule. Tunability in the SERS for the account of different surface areas poses by the different MoS2 sample has been well explored. Charge transfer mechanism for ultrafast SERS detection and enhanced photodegradation activity has been proposed and explained precisely.

Application of Novel C-TiO2-CFA/PAN Photocatalytic Membranes in the Removal of Textile Dyes in Wastewater

The existence of dye effluent in environmental water bodies is becoming a growing concern to environmentalists and civilians due to negative health effects. In this study, a novel poly(acrylonitrile)-membrane-supported carbon-doped titanium dioxide–coal fly ash nanocomposite (C-TiO2-CFA/PAN) was prepared and evaluated in the removal of textiles dyes (methyl orange and golden yellow) in water. The C-TiO2-CFA nanocomposite was prepared via sol-gel synthesis and immobilized on PAN membrane prepared via phase inversion technique. The photocatalyst was characterized by FTIR, XRD, BET surface area analysis, SEM, EDX, and DRS. FTIR analysis confirmed the existence of the expected functional groups, and XRD revealed that the C-TiO2 was predominantly in the anatase phase, which exhibited the highest photocatalytic activity. The optimum C-TiO2-CFA photocatalyst load on the PAN membrane was 2% w/w, and it achieved degradation efficiencies of 99.86% and 99.20% for MO and GY dyes, respectively, at pH 3.5, using a dye concentration of 10 ppm, under sunlight irradiation, in 300 min. The novel 2% C-TiO2-CFA/PAN photocatalytic membrane proved to be very effective in the removal of textile dyes’ water. Three reusability cycles were carried out, and no significant changes were observed in the photocatalytic efficiencies. Immobilization on PAN membrane allowed easy recovery and reuse of the photocatalyst.

Constructing Ag2O nanoparticle modified TiO2 nanotube arrays for enhanced photocatalytic performances

Currently, the silver-based semiconductor modified TiO2 nanotube arrays (TiO2 NTA) for the improved photocatalytic treatment of industrial waste water have been a hot topic. The simple synthesis and environmental application of photocatalysts with excellent photocatalytic ability is still a big challenge. Herein, We reported the successive ionic layer adsorption and reaction (SILAR) preparation of Ag2O nanoparticles on TiO2 NTA surfaces. The different deposition cycles were performed to investigate the influence of Ag2O deposition amounts on the photoelectrochemical activity. Results revealed that the S-10 fabricated with 10 SILAR cycles had the impressive photocatalytic and photoelectric conversion performances. The visible light photovoltage and photocurrent of S-10 electrode were −0.20 V and 463.2 μA/cm2. Moreover, the photocatalytic degradation efficiencies of MO, RhB and MB dyes achieved 67.40%, 59.19% and 93.89%, respectively. Further increasing the irradiation time, the mineralization degree of organic dyes were improved up to 71.28%, 60.31%, and 92.58% after 6 h solar irradiation. Cr(VI) ions were also dramatically removed by photocatalysts. The remarkable photocatalytic performance of Ag2O/TiO2 NTA would exhibit attractive prospect in the industrial waste water purification.

Recycling of Agriculture Wastes for Efficient Removal of Methyl Orange Dye Using Batch Adsorption Unit

The main purpose of this study is to exam the ability of agriculture wastes without pretreatment such as date palm fibers (DPF), sawdust (SD), rice husk (RH) as low-cost adsorbents for removing of methyl orange dye (MO) from industrial wastewater. The operating parameters were designed under isothermal batch conditions to study the influence of pH (2-10), initial concentration of MO dye (100-500) mg/l, adsorbent dose (0.1-1) g/100 ml and contact time (10-150) min. The optimum conditions were pH = 2, the initial concentration of dye = 100 mg/l, the amount of adsorbent dose = 0.6 g/100ml and 120 min contact time. At these conditions, the maximum removal efficiency was 95%, 86% and 77% for DPF, SD, and RH, respectively. There are two advantages to this work, it can remove MO dye from wastewater and disposal of agricultural wastes. The equilibrium results were compared with the most common isotherm adsorption models, Langmuir and Freundlich models, to measure the conformity of results obtained. It was fitted with the two models with a high correlation coefficient (R2) for all adsorbents.

Synthesis and Investigation of Fe doped SnO2 Nanoparticles for Improved Photocatalytic Activity under Visible Light and Antibacterial performances

ABSTRACT Pristine and iron (Fe) doped tin oxide (SnO2) nanoparticles (NPs) were prepared by using a microwave aided co-precipitation method and the effect of doping on structural, optical and photocatalytic belongings have been investigated by XRD, FTIR, HR-SEM with EDX mapping, UV-Vis. DRS and Photoluminescence (PL) spectra respectively. XRD analysis has revealed a tetragonal SnO2 structure and the typical crystalline size was found to be between 28 nm and 17 nm. Photoluminescence spectra displayed a robust UV emission broadband peaking around 392.5 nm. The 4 % of Fe doped SnO2 NPs had higher photocatalytic action associated with the pristine and 2 % of Fe-SnO2, and maximum MO dye degradation efficiency of 87.2 % has been attained 200 min under visible light Moreover, the studies prove that antibacterial activities of produced Fe doped SnO2 NPs have a momentous performance against various gram-positive (G+) and gram-negative (G-) bacteria.

Effect of annealing temperature on structural, optical and visible light photocatalytic performance of CaTiO3 catalysts synthesized by simple sol-gel technique

This work, simple wet chemical route has been adapted to prepare calcium titanate (CaTiO3) catalyst nanopowders. The nature of crystalline structural, morphological, optical and textural properties of the products was monitored through XRD, SEM, TEM, Raman, UV, PL and BET analysis. Orthorhombic crystalline phase with clear spherical are found in the XRD and TEM results. There is no trace in the impurity of the products, which denotes that product purity nature. The optical band gap energies (3.03–2.82 eV) and rapid generation electron-hole with presence of light was identified through UV and PL results. Mesoporous nature (34.2 nm) with huge surface area (97.5 m2/g) was identified through BET analysis. The photocatalytic results exposed that the 900 °C annealed CaTiO3 catalyst shows fabulous degradation efficiency (88%), high apparent constant (0.0578 min−1) and long term stability towards MO dye under visible light illumination. The improved photocatalytic activity of CaTiO3 is due to the narrowing the band gap energy and prevent the recombination process of electron-hole pairs. The improved mechanism of the proposed photocatalyst was also discussed in detail.

Effective coupling of Cu (II) with BiOCl nanosheets for high performance electrochemical supercapacitor and enhanced photocatalytic applications

A facile solvothermal route is developed to prepare ultrathin Cu (II) modified BiOCl nanosheets for promising photocatalytic and electrochemical energy storage applications. The modification of BiOCl nanosheets with Cu (II) significantly enhanced the photocatalytic activity for degradation of methyl orange dye (MO) and electrochemical energy storage in symmetric supercapacitor. The amount of Cu (II) on BiOCl nanosheets was optimized by meticulously controlling the Cu (II) loading as 2, 4, 6 and 8 wt% to achieve the best possible photocatalytic activity. The crystalline nature, elemental composition, morphology and optical properties of prepared nanosheets are studied in detail using XRD, XPS, TEM and UV–vis spectroscopy analyses, respectively. The catalyst prepared with 6 wt% Cu (II) loading performed the best performance with 97% of MO degradation at 10 mg/L (0.03 mM) MO dye concentration within 50 min in visible light. The high activity was attributed to the increased surface area of the catalyst from 22 to 43 m2 g−1 upon Cu (II) over ultrathin BiOCl nanosheets. Also, the Cu (II) modification, permitting adsorptions of more number of active species and could help in restricting the recombination rate by allowing easy transit of excited electrons to Cu (II). Also, a highly stable performance is achieved when it was reused for five times. The BiOCl and Cu (II) modified BiOCl nanosheets with different Cu loading were studied for electrochemical supercapacitor application. The 6 wt% Cu (II)/BiOCl showed a high specific capacitance of 155 F/g with high specific capacitance retention of 101% after 5000 cycles.

Catalytic reduction of organic and hexavalent chromium pollutants with highly active bimetal CuBiOS oxysulfide catalyst under dark

Highly active CuBiOS bimetal oxysulfide catalysts were successfully prepared via a feasible method. The resulting CuBiOS powder catalysts were characterized by different techniques. The catalytic activities of the samples were also checked by the reduction of toxic organic of 4-NP, organic dyes (MO, MB, RhB), and chromium (Cr(VI)) in the presence of NaBH4 under dark condition. The results showed that CuBiOS catalyst prepared with 0.3 mL of N2H4 amounts had the highest catalytic activities towards the reduction of 4-NP, MO, MB, RhB, and Cr(VI). Complete reduction of 4-NP and Mb were achieved within 2 min. In the case of MO and RhB dyes, it took only 3 min to reduce above 99% by CuBiOS-2 catalyst. The Cr(VI) reduction was also achieved and 99.7% was completed within 20 min under dark condition. The possible mechanism for the reduction of 4-NP was proposed. Therefore, the bimetallic CuBiOS catalyst could have high potential and a candidate in the wastewater treatment technologies.

Construction of BiVO4 microspheres sensitized TiO2 NTAs for the enhanced photocatalytic mineralization of organic dyes

In the present work, BiVO4 microspheres were deposited on TiO2 NTAs via the solvothermal method using urea as the mineralizer. The binary heterojunction formation significantly enhanced the solar response region and intensity, and the electron transfer path was built at the interface of two semiconductors, which was the main reason for the enhanced photoelectrochemical and photocatalytic performances. The S-2 electrode prepared with urea concentration of 2 mol/L displayed the high visible light photocurrent of 73.76 μA/cm2 and photovoltage of −0.30 V. Furthermore, the S-2 photocatalyst also showed excellent photocatalytic decoloration ability of MO, RhB and MB dyes, and the corresponding decomposition efficiencies were 55.82%, 41.62% and 89.90% under solar irradiation. Except for the organic dyes, Cr(VI) ions also could be reduced into Cr(III), and the photocatalytic efficiency achieved 74.05% after 3 h solar irradiation. The active group and photocatalytic mechanism were proposed to illuminate the essential reason. The experimental results indicated that the novel BiVO4/TiO2 NTAs with binary heterojunction are attractive photocatalysts for the dyeing and printing water treatment.

Metal oxides nanomaterials for the photocatalytic mineralization of toxic water wastes under solar light illumination

Metal oxides based on Cu-Sr, Sr-Cd and Cd-Cu were synthesized by mild and cost effective co-precipitation method. XRD and SEM were utilized in order to investigate the phase structure, composition and morphology of as synthesized metal oxides. Crystallite size calculated through XRD was found to be 40.36, 49.97 and 82.62 nm for Cu-Sr, Sr-Cd and Cd-Cu metal oxides whereas, SEM indicated particle size ranged from (44–88)nm. Elemental contents, functional groups and thermal stability of these metal oxides were determined via XPS, FTIR and TGA. Band gap energies were measured as 1.57, 1.64 and 1.61 eV while, BET analysis indicated surface area ∼9.86, 1.99 and 49.78m2/g with total pore volume/average aperture size ∼0.0348 ml/g/1.0934 nm, 0.0127 ml/g/0.1101 nm and 0.1080 ml/g/0.9254 nm for Cu-Sr, Sr-Cd, and Cd-Cu metal oxides respectively. These metal oxides were used as photocatalysts for the degradation of MB and MO dyes under solar light irradiation showing higher catalytic activity with 86, 78 and 67 % degradation for MB dye, while 80, 50 and 69 % degradation was observed for MO dye within total time of 180 min. Effect of various operational parameters such as catalyst loading, pH, and various scavengers was evaluated in detail. Morever, in-situ investigations were also carried out in order to determine the active species and hence the mechanism for catalytic reactions. These results for dye detoxification and corresponding reaction mechanism suggested the synthesized metal oxides as promising candidates for real toxic water wastes cleanup applications.

Polysulfonamide coating layer polymerized by1,3-disulfonyl chloride and polyethylenimine to achieve acid resistant TFC membranes

In this work polysulfonamide membranes are presented that are prepared by the interfacial polymerization of polyethylenimine (PEI) and benzene-1,3-disulfonyl chloride (BDSC) on porous polyvinylidenefluorid support membrane. The thin film composite (TFC) polysulfonamide membranes show superior acid stability as compared to conventional polysulfonamide membranes that are derived from monomeric amine and benzene-1,3-disulfonyl chloride. The polysulfonamide membranes show exceptionally strong resistance towards nucleophilic attack induced by extreme acidic conditions. This is verified by the dyes rejection performance in 20%(w/v) H2SO4 and 2.5%(w/v) HNO3 aqueous solution at 70 ± 5 °C for 24 h. PEI-PSA and PEI/PIP-PSA membranes were considerably stable in two acids. In contrast, the durability of PEI/MPD-PSA was lower than the other two. The changes in CV and MO dye rejection were −3.15% and −2.19%, and −1.11%, −5.6% for PEI-PSA and PEI/PIP-PSA, respectively after H2SO4 soaking while they were −20% and −15.9% for PEI/MPD-PSA. Moreover, the changes in CV and MO dye rejection were −15.7% and −14.3%, and −7.8%, −5.7 % for PEI-PSA and PEI/PIP-PSA, respectively after HNO3 soaking while they were −17.7% and −10.2% for PEI/MPD-PSA.

Catalytical properties of the polyanilylin-MnO2 composite in organic dye decoloration reactions

This work is devoted to the study of the regularities of the oxidation reactions of the dye (methyl orange) using hydrogen peroxide in the presence of a heterogeneous catalyst (PAn–MnO 2 composite), which we synthesized to increase the speed of the specified chemical reaction. When added to the reaction mixture containing H 2 O 2 and organic dye, the catalyst, which is a composite of the conjugated polymer and the transition metal oxide, can generate hydroxyl radicals, which are powerful oxidizing agents. This allows for higher rates of the dye bleaching reaction to be achieved compared to those occurring when using H 2 O 2 without a catalyst. The polyaniline–MnO 2 composite was synthesized by the method of oxidative polycondensation of aniline under the action of MnO 2 , which was dispersed in 100 ml of 1.15 mol/l aqueous sulfuric acid, the reaction was carried out at a ratio of MnO 2 : An = 1:1. In the infrared spectrum of the polyaniline–MnO 2 composite, a wide range of absorption peaks between 500 and 800 cm -1 , which are related to the vibrations of Mn–O atoms in MnO 6 octahedra, are observed; the peaks at 1 300 and 1 243 cm -1 belong to the C–N valence vibrations for the benzoid form (secondary aromatic amine), and the peak at 1 142–1 153 cm –1 belongs to the quinoid form of the doped PAn, the peak at 800 cm -1 refers to the vibrations of atoms in the C–C and C–H groups of the benzoid form. An intermolecular interaction appears to occur between the polyaniline quinoid and benzoid groups and Mn–O, which are part of the composite. We have studied the catalytic properties of the composite (PAn–MnO 2 ) and the original manganese oxide in the decolorization reactions of the MO dye under the action of H 2 O 2 . It has been shown that in the presence of manganese oxide, the oxidation of MO occurs faster than during the action of the composite (PAN – MnO2). The catalytic reaction constant in the first case has a relatively higher numerical value (1.85 × 10 -4 s -1 and 0.23 × 10 -4 s -1 , respectively). Keywords: polyaniline, composite, MnO 2 , catalysis, methyl orange

RETRACTED: Narrow band gap reduced TiO2-B:Cu nanowire heterostructures for efficient visible light absorption, charge separation and photocatalytic degradation

Hydrothermally synthesized TiO2-B single-crystalline NWs were uniformly Cu-decorated via co-precipitation method to grow hybrid TiO2-B:Cu–NWs. Starting from commercial TiO2 NPs, systematic evolution of TiO2-B, R–TiO2-B and R–TiO2-B:Cu NW-structures in steps, identified a gradual narrowing of band gap from 3.23 to 2.20 eV. Generation of Ti3+ and oxygen vacancy (Ov) related defect states in TiO2 lattice facilitates enhancing absorption of visible light and also inhibit faster charge recombination via trapping of photogenerated charge carriers. Cu2O nanoparticles intimately attached with TiO2 NW surface enhance the charge carrier separation via interfacial charge transfer between Cu2O and TiO2, involving direct Z-scheme mechanism. Further, metallic copper, being present with an intermediate band gap, can promote electron tunneling across Cu-Cu2O-TiO2 ternary hetero-junctions and dissociate more efficiently the photoexcited electrons and holes from individual pairs and make those amply available for dye degradation reactions which proceed more efficiently in spite of the reduced surface area and porosity of the hetero-structured photocatalyst. Strongly reductive electrons (e−) in the CB of Cu2O produce highly reactive superoxide radicals (O2−) which dominantly contribute in dye degradation, while hydroxyl radicals (OH) produced via oxidation by holes (h+) in the VB of TiO2 also degrade the dye molecules in a relatively lesser significance. The R-TiO2-B:Cu0.2 NW catalyst degrades the MO dye very rapidly with a rate constant ~0.41 min−1 and an efficiency of dye degradation ~91%, and the MB dye even faster with a rate constant ~0.54 min−1 and an efficiency of dye degradation of ~96%, during 60 min of visible light exposure, which are significantly high as compared to the data available in the contemporary literature.

Synthesis and characterizations of BiOCl nanosheets with controlled particle growth for efficient organic dyes degradation

In this report, we considered the control of electron-hole separation, oxygen vacancy formation, particle size, and morphology together is supposed to boost the catalytic activity of the materials. Hence, BiOCl photocatalysts were synthesized by a systematic control of particle growth along reactive (001) plane using simple hydrolysis method in KCl saturated aqueous solution with simultaneous UV light treatment. The materials were characterized using different techniques and the photocatalytic activities were evaluated for degradation of different kinds of organic dyes. 20-BiOCl prepared with 20mmol KCl showed 99.9% RhB degradation within 10min of visible light irradiation. From kinetics data, 20-BiOCl showed 7 and 3 times higher rates on RhB dye degradation than untreated 20-BiOCl and unsaturated 5-BiOCl, respectively. Furthermore, 20-BiOCl catalyst also exhibited almost complete degradation of RhB, MO, and MB dyes under UV light irradiation. Supper oxide (O2.−) and hydroxyl (OH) radicals are identified as the main active species on the degradation of RhB dye under visible light irradiation. Both KCl saturation and UV light treatment during synthesis of BiOCl catalysts play a crucial role to the extraordinary photocatlytic activities.

Selective adsorption of anionic dyes from aqueous solution by a novel β-cyclodextrin-based polymer

Abstract β-cyclodextrin (β-CD) was firstly crosslinked by tetrafluoroterephthalonitrile and then modified by ethanolamine (EA) to form a novel β-cyclodextrin-based polymer (EA-CDP). The microstructure and the properties of the EA-CDP were characterized by SEM, MIP, 13C NMR, FTIR, water contact angle measurement, zeta potential measurement, and TGA. The resultant EA-CDP could effectively select the anionicmethyl orange (MO) dye from the mixed-dye aqueous solution of MO and cationic methylene blue (MB) dye. The absorption capacity of the EA-CDP for anionic dyes including MO and Congo red (CR) increased with the decreasing pH value. The pseudo-second-order kinetic was more ideal to describe the absorption behavior of EA-CDP for MO and CR than the pseudo-first-order model. According to the fitting result of the Langmuir equation, the maximum absorption capacity of the EA-CDP for MO and CR reached as high as 602 mg/g and 1085 mg/g, respectively. Such a high absorption capacity could be ascribed to the triple absorption effects of the EA-CDP for anionic dyes including porous network capture, inclusion complextion, and electrostatic attraction.