Dye Acid Red Research Articles

Structural, Thermal, Magnetic and Electrical Properties of Polyaniline/CoFe2O4 Nano-composites with Special Reference to the Dye Removal Capability

CoFe2O4 nanoparticles were synthesized using environmentally friend sucrose auto-combustion method. PANI/CoFe2O4 nano-composites were prepared via in situ polymerization of aniline in the presence of various ferrite ratios. The structure, thermal, and electro-magnetic properties of the nano-composites were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), thermo-gravimetric analysis (TG), vibrating sample magnetometer (VSM), ac-conductivity and dielectric measurements. The structural properties exhibited the existence of the two phases and indicated core–shell structure. This core–shell was confirmed further through thermal and electrical properties measurements. The different PANI properties such as thermal stability, magnetic and the dielectric were obviously improved by ferrite incorporation whereas its conductivity remained unaffected. The nano-composites (10 and 30%) were investigated for the efficient removal of acid red dye (AR) from wastewater. In this category, the effect of various parameters including pH, contact time, temperature and mass on the removal capacity were investigated. The adsorption kinetics indicated that the adsorption followed the pseudo-second-order equation model through spontaneous endothermic adsorption process. The incorporation of ferrite within PANI increases the magnetic sensitivity of the nano-composite, which will facilitate the ease of separation of dispersed nano-composite from aqueous solutions using simple magnet after dye removing process. Generally, the moderate magnetic sensitivity, cost effective synthesis besides the acceptable obtained adsorption capability of the entire nano-composites could enhance their future use in the remediation applications.

Synthesis of biphasic nanomaterials based on ZnO and SnO2: Application towards photocatalytic degradation of acid red dye

Zn2SnO4/SnO2 and ZnO/SnO2 biphasic nanocatalysts have been synthesized by a facile solvothermal method using ethylene glycol (EG) as solvent in three different ways maintaining the pH of the solution at either 3 or 9 followed by calcination at 700 °C. The nanocatalysts are characterized by different techniques to investigate their structure, composition, morphology and optical properties. The XRD results indicate the formation of pristine biphasic composites. The UV-absorbance and photoluminescence spectra confirms the formation of biphasic composites as well as presence of large number of defects in the prepared nanocatalysts. The biphasic nanocomposites possess better photocatalytic activity towards the degradation of Acid Red-183 (AR-183) dye than pristine SnO2 and ZnO nanoparticles. This is mainly due to better charge separation, minimal recombination rate of charge carriers and defect-riched structures of nanocatalysts.

Degradation of Acid Red 8 Dye Using Photo-Fenton Reaction Mediated by Titanium Modified Catalysts

Catalysts prepared by co-precipitation of iron and titanium were evaluated in heterogeneous photo-Fenton degradation of the azo dye Acid Red 8 under blacklight irradiation. Materials with different titanium contents (0 < Ti/Fe < 0.6) were characterized using X-ray diffractometry, scanning electron microscopy, X-ray fluorescence spectroscopy, specific surface area and X-ray photoelectron spectroscopy. Hematite was identified as main phase in materials with lowest Ti content, while titanomaghemite was predominant at high Ti content. Highest degradation was obtained using titanium free catalyst due to iron leaching, which promoted a homogeneous reaction. Addition of Ti led to a heterogeneous process with a maximum when Ti/Fe = 0.40 achieving 0.76 mol of dye mineralized per mol of soluble iron after 90 min, using 10 mmol L-1 H2O2 at pH 5.6, value at least three times higher than that observed for catalysts with lower Ti content. The results indicate that Ti stabilizes the catalyst and increases its heterogeneous activity in photo-Fenton process.

Adsorption of Acid Red dye from aqueous solution using quaternized chitosan microspheres

In this study, quaternized chitosan microspheres (QCMS) were prepared and their adsorption performance of Acid Red 18 from aqueous solution was studied. Equilibrium was attained within 120 minutes and maximum removal of 94.06% was achieved. Langmuir and Freundlich isotherm models have been investigated. The maximum capacity obtained from the Langmuir model is 142.15 mg.g(-1). Pseudo-first order and pseudo-second order kinetic models have been used for experimental data. The kinetic process was described by a pseudo-second-order rate equation very well. The calculated thermodynamic parameters (Delta H degrees = -12.67 kJ.mol(-1); Delta G degrees = -4.67 to -5.61 kJ.mol(-1) and Delta S degrees = -24.78 K-1.mol(-1)) showed that the adsorption of Acid Red 18 is feasible, spontaneous and endothermic in nature. The results of the present study indicated that the QCMS could be considered as a potential adsorbent for Acid Red 18 in aqueous solutions.

Removal of Acid Red dye from aqueous solution using zero-valent copper and zero-valent zinc nanoparticles

Removal of Acid Red dye from aqueous solution using zero-valent copper and zero-valent zinc nanoparticles

Facile synthesis of coral-like hierarchical polyaniline micro/nanostructures with enhanced supercapacitance and adsorption performance

We presented a newly facile approach to scalable synthesize three-dimensional (3D) coral-like polyaniline (CL-PANI) hierarchical micro/nanostructures. The CL-PANI composed of well-defined nanowires with ca.20 nm was self-assembled by in situ conventional chemical polymerization with a different charging sequence. Electron microscopy, UV-Vis spectroscopy, X-ray diffraction, and nitrogen adsorption-desorption studies showed that CL-PANI possessed unique mesoporous structure and highly crystallinity which could promote rapid ion diffusion and charge transfer. Electrochemical experimental results showed that the as-prepared CL-PANI electrode had a superior electrochemical capacitance performance with a relatively high specific capacitance of 817 F g−1 at a current density of 0.5 A g−1 and a great rate capability of 67% specific capacitance retaining from 0.5 to 20 A g−1. Meanwhile, CL-PANI exhibited an enhanced adsorption performance of azo dye Acid Red G (ARG) from aqueous solution with a Langmuir maximum adsorption of 310.2 mg g−1 at pH 2.0, 298 K. This study offers a simple and cost effective path for scalable synthesis of PANI materials for supercapacitor and adsorption application.

Application of TiO2-nanotubes/PbO2 as an anode for the electrochemical elimination of Acid Red 1 dye

In this study, galvanostatic electrolysis, through the use of the platinum supported on Ti (Ti/Pt) and Ti/TiO2-nanotubes/PbO2 anodes, was conducted in an electrochemical cell with 0.2 L of solution containing 100 mg dm−3 of the textile dye Acid Red 1 (AR1) using Na2SO4 as supporting electrolyte, applying 7.5 and 60 mA cm−2. From the voltammetric curves, it was possible to understand that Ti/TiO2-nanotubes/PbO2 electrode has high oxygen evolution overpotential than Ti/Pt anode. A direct electron transfer reaction is attained between the dye molecules and Ti/Pt surface, at lower currents. Conversely, the AR1 oxidation involves water decomposition intermediates, mainly ·OH radicals at Ti/TiO2-nanotubes/PbO2 anode. The electrolytic process was monitored by the UV–visible spectrometry and the chemical oxygen demand (COD). Results clearly show that Ti/TiO2-nanotubes/PbO2 anode performs better than Ti/TiO2 in removing ARI due to the electrosynthesis of strong oxidants on its surface (·OH and persulfates), achieving a higher oxidation rate, higher current efficiency, and less energy consumption than Ti/Pt electrode.

Biosorption of Acid Red P-2BX by lichens as low-cost biosorbents

ABSTRACTThe aim of this study is to examine the dye biosorption properties of lichen species called Cladonia convoluta and Evernia prunastri. Since lichens are extensively found in the environment, their suitability as a cheap adsorbent has been investigated in this study. The optimal parameters for textile dye biosorption were also determined. The dried lichen biomass showed better dye biosorption capacity than ash lichen biomass. C. convoluta had better dye biosorption capacity than E. prunastri. Dye biosorption rate was found as 71.41% at optimal conditions. This study concluded that C. convoluta was a successful and cheap biosorbent for treatment of water contaminated by Acid Red P-2BX dye.

Highly crystalline polyaniline nanofibers coating with low-cost biomass for easy separation and high efficient removal of anionic dye ARG from aqueous solution

The separation of nanostructured absorbents from the aqueous solution has been the challenge for their practical application due to their small colloidal size. Here, highly polyaniline nanofibers, prepared via a simple polymerization method at room temperature using ferric chloride (FeCl3) as an oxidant, were coated on the alkali-pretreated cost-efficient and reusable biomass, i.e, sawdust (PANI-NFs/SD). The obatined PANI-NFs/SD was demonstrated to exhibit easy separation characteristic from SD and highly effective adsorption performance from PANI-NFs. It was characterized via FT-IR spectroscopy, scanning electron microscopy, thermogravimetric analysis, X-ray diffraction and Zeta potential measurements. The adsorption of anionic azo dye Acid Red G (ARG) onto PANI-NFs/SD from aqueous solution was carried out at different solution pH, initial dye concentration, adsorbent dosage and temperature. The calculated thermodynamic parameters suggested the feasible, spontaneous and endothermic nature of ARG adsorption onto PANI-NFs/SD. The fitted data showed that the adsorption process followed pseudo-second-order kinetics model and Freundlich isotherm model. The maximum experimental adsorption capacity for ARG at pH 2.0 was found to be 212.97 mg g−1 at 308 K. Moreover, the regeneration experiment revealed that PANI-NFs/SD was an effective reusable adsorbent without obvious loss of its original capacity after 29 sequential adsorption-desorption cycles. Mechanism studies indicated that the excellent effective adsorption performance of PANI-NFs/SD was associated with highly doping chemistry of PANI-NFs with high crystallinity.

In situ growth of cube-like AgCl on montmorillonite as an efficient photocatalyst for dye (Acid Red 18) degradation

AgCl was incorporated with clay montmorillonite to improve the individual catalytic or adsorption performance. A green method was proposed to synthesize AgCl/montmorillonite composite by intercalating silver-ammonia complexes into the interlayers of montmorillonite followed by reacting with HCl vapor to in situ form AgCl particles on montmorillonite. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscope, energy dispersive X-ray spectroscopy, transmission electron microscope, Brunauer–Emmett–Teller analysis, X-ray photoelectron spectra, and UV–vis diffuse reflectance spectrum. It was shown that AgCl not only intercalated into the interlamination of montmorillonite but also anchored on its exterior surfaces. AgCl on clay surface was cube-like particles, which were dominated by the higher activity of {1 0 0} planes. The photocatalytic activity of AgCl/montmorillonite (AgCl-Mt) composites were evaluated by degradation of azo dye Acid Red 18 (AR18) under UV-irradiation. AgCl in AgCl-Mt composites had an optimum amount. When 3CEC of silver-ammonia was used to prepare [Ag(NH3)2]+-exchanged Mt, the obtained 3AgCl-Mt had the best activity. The degradation of 50 mL AR18 at pH 6 with 1 g L−1 of catalyst only needed 10 min. The low pH and dye concentration, and high catalyst loading favored the removal of dye. Moreover, the superoxide radicals and holes were found to be major reactive species responsible for the photocatalytic degradation of AR18. PL revealed that besides reducing the aggregation of AgCl and tailoring morphology of AgCl, montmorillonite also suppressed the combination of photogenerated electron-hole pairs, and thus enhanced the photocatalytic activity and stability. This study may offer an efficient approach for fabricating silver-halide-based composite photocatalysts for environmental cleanup.

Catalytic performance of quinone and graphene-modified polyurethane foam on the decolorization of azo dye Acid Red 18 by Shewanella sp. RQs-106

Quinone-modified graphene powder is not reusable in bio-treatment systems, and the roles of quinone and graphene during extracellular electron-transfer processes remain unclear. In this study, we prepared anthraquinone-2-sulfonate and reduced graphene-oxide-modified polyurethane foam (AQS-rGO-PUF) and found that AQS-rGO-PUF exhibited higher catalytic performance on Acid Red 18 (AR 18) bio-decolorization compared with AQS-PUF and rGO-PUF. We observed a significant synergistic effect between AQS and rGO in AQS-rGO-PUF-mediated system in the presence of 50 μM AQS and 1.63 mg/L rGO. The synergistic effect was mainly attributed to electron transfer from AQS to rGO either directly or via flavins secreted by strain RQs-106, and ultimately to AR 18, accounting for ∼33.47% of AR 18 removal during AQS-rGO-PUF-mediated decolorization. Additionally, AQS-rGO-PUF exhibited good mechanical properties and maintained its macroporous structure. Furthermore, after eight rounds of experiments using AQS-rGO-PUF, the bio-decolorization efficiency of AR 18 retained >98.18% of its original value. These results indicate that the combination of AQS-rGO-PUF and Shewanella strains show potential efficacy for enhancing the treatment of azo-dye-containing wastewater.

Nanocomposite-Based Aminated Polyethersulfone and Carboxylate Activated Carbon for Environmental Application. A Real Sample Analysis

Aminated polyethersulfone (PES–NH2) has been synthesized and used with carboxylated activated carbon (AC–COOH) as an adsorbent using two different methods: in situ and ex situ techniques. The chemical modification of polyethersulfone (PES) to introduce –NH2 functions was used to overcome the hydrophobicity of PES which maximizes its use in water treatment applications whereas applying AC–COOH to this polymer provides a promising effective method as an adsorbent-separation technique to remove dye pollutants from wastewater. The structure and characterization of aminated polyethersulfone with carboxylated activated carbon (PES–NH2–AC–COOH) were identified using proton nuclear magnetic resonance (1H-NMR), Fourier transform infrared (FT-IR spectroscopy), X-ray diffraction (XRD), thermal analysis (TA), and a scanning electron microscopy (SEM). The performance of PES–NH2 in situ and ex situ with AC–COOH was tested for the adsorption of cationic (methylene blue) and anionic (acid red 1) dyes from an aquatic environment. The results of the study showed a better thermal stability for the PES–NH2 with 20% AC–COOH with both in situ and ex situ techniques as well as an excellent adsorption performance in comparison with the bare PES–NH2. The resultant polymers displayed significantly high adsorption rates for the acid red dye (60% and 68%) and methylene blue dye (61% and 88%) by PES–NH2 with AC–COOH using in situ and ex situ techniques, respectively, in comparison with the control (PES–NH2) which showed lower adsorption rates for both dyes (21% for acid red and 33% for methylene blue). Lastly, the study experimental measurements found the most suitable model to describe the kinetic behavior of the acid red dye adsorption by our developed polymer (by PES–NH2 with AC–COOH) to be the pseudo-second-order kinetic model.

Testing the Ability of Using Cement Kilns Waste for Removing Acid Dyes Wastewater by Adsorption

This investigation deals with the use of cement kiln dusts waste (CKD) as adsorbent for removal two kind of acid dyes from simulated wastewater. cement kiln dusts waste prepared by dried at 60C°. The effect of pH: 2-12, contact time: 20- 180 min, sorbent weight: 0.5- 4.0 g were considered. The optimal pH value for acid dyes adsorption was found to be 2.5 for acid red dyes(ARD)and 6.5 for acid blue dyes (ABD). The equilibrium data were analyzed using Langmuir and Freundlich isotherm models. Freundlich model was found to fit the equilibrium data very well with high-correlation coefficient (R2). The adsorption kinetics was found to follow pseudo-second-order rate kinetic model, with a good correlation (R2 > 0.95 and 0.94) for acid red dyes(ARD) and acid blue dyes (ABD). respectively. The results showed that the cement kiln dusts waste was found to be an attractive low cost adsorbent for the treatment of wastewater.

Beading of Co1-xZnxFe2O4 nanoparticles on MWCNTs. synthesis characterization, effect of Zn-substitution and dye removal capability

Multi-walled carbon nanotubes (MWCNTs) coated with magnetic Co1-xZnxFe2O4 nanoparticles (x = 0.0–1.0) were prepared via novel gelatin method. The synthesized nano-composites were characterized using X-ray diffraction, Fourier transform infrared (FT-IR) and transmission electron microscopy (TEM) to clarify the nano-composites formation and discuss the coating mechanism. The effect of the ferrite presence along with Zn-substitution on thermal stability, magnetic and conductivity characteristics was investigated and discussed. The addition of CoFe2O4 obviously decreases stability through catalyzing MWCNTs oxidative decomposition while increasing Zn-content inhibit it. The changes in the magnetization values by Zn addition was discussed in the view of changing cation distribution. All the investigated nano-composites exhibited metallic conduction characteristic of MWCNTs without any indication for any changes with Zn-substitution. The magnetic sensitivity along with high surface area exhibited by the entire nano-composites enhanced their use in adsorption removal of acid red (AR) toxic dye from aqueous solutions. In this category, the nano-composites with x = 0.0, 0.4 and 0.8 were examined to study the efficiency of the adsorption process and to investigate the effect of Zn-content on the adsorption. The effect of various parameters including pH, contact time, temperature and mass on the removal efficiency was also studied. In addition, the kinetic as well as the thermodynamic parameters were investigated and discussed.

Photocatalytic Degradation of Azo Dye Acid Red 14 from Aqueous Solutions Using MWCNTs Nanocatalyst

Photocatalytic Degradation of Azo Dye Acid Red 14 from Aqueous Solutions Using MWCNTs Nanocatalyst

Removal of Acid Red 18 (Azo-Dye) from Aqueous Solution by Adsorption onto Activated Charcoal Prepared from Almond Shell

One of the most important environmental pollutants is azo dyes in textile wastewater. In this study, the removal of azo dye Acid Red 18 (AR 18) with initial concentration of 25-100 mg L−1 in aqueous solution by the adsorption process onto activated charcoal prepared from almond shell (AC-AS) was investigated. The effects of initial pH (2-12), contact time (15-120 min), adsorbent (0.2-2 g L-1) and initial concentration of AR 18 (25-100 mg L-1) on the removal efficiency of AR 18 solution were investigated. All experiments were performed on a synthetic wastewater. The efficiency of dye removal and Freundlich and Langmuir adsorption isotherms were compared as a function of decolorization and adsorption and kinetic behavior of AR 18. The maximum removal efficiency of AR 18 (i.e., 90.83%) was occurring with pH 2, contact time of 60 min, initial dye concentration of 75 mg L-1 and the adsorbent dose of 0.8 g L-1. The removal of AR 18 followed the Frundlich isotherm model (r2&gt;0.994). Fitting of obtaining data onto kinetic models showed the pseudo second-order reaction kinetics with respect to the dye concentration. This investigation revealed adsorption onto activated charcoal prepared from almond shell presents good efficiency for solution decolorization.

A novel continuous electroflotation cell design for industrial effluent treatment

The performance of a continuous flow electroflotation (EF) unit designed for industrial effluents treatment was investigated. The employment of synthetic wastewater composed of some heavy metal ions (Cr3+, Cu2+ and Pb2+), soluble dyes (Acid Red 1 and Basic Violet 3), and ultrafine particles (copper metal and copper oxide) was set for studying the cell parameters. The affecting parameters of the EF unit which are current density and type and ionic strength (conductivity) and feed flow rate were studied. The continuous flow EF unit was employed for the treatment of different industrial effluents which was supplied by Textile, Tannery and Wood factories. For synthetic wastewater, the removal efficiency of industrial effluents increased with increasing current density and ionic strength. DC current causes passivation of the anode, thus AC current was preferred. The lower feed flow rate increased the removal efficiency but consumed more power. The removal efficiency was achieved up to 95% at 25 °C, 5 V and an AC current intensity of 1 A with a feed flow rate of 50 ml/min (3 l/h). The energy consumption was 1.67 kWh/m3. For different industrial effluents, the removal efficiency approached up to 90%, at 25 °C, 5 V and an AC current intensity of about 1 A and a 30 ml/min feed flow rate. The energy consumption was about 3 kWh/m3. The removal efficiency could be increased up to about 99% by a further cleaning step with total energy consumption of about 6 kWh/m3.

Immobilized Nanoparticles on Polymeric Carriers for Removal of Reactive Textile Dyes in Aqueous Media

In the waste water treatment, especially in the removal of textile dyes from aqueous media, it is known that photocatalytic oxidation technique has tremendous advantages compared to conventional techniques, such as quick oxidation, prevention of polycyclic end products, and oxidation of organic species even at µg/L concentrations. Heterogeneous photocatalysis consisting semiconductor oxides such as TiO 2 has been effectively implemented in aqueous media. However, problems such as catalyst separation and catalyst recovery are encountered when powder catalysts are used. Meanwhile, the fixation of oxides by any method reduces the catalytic effıciency. In this study, nanoparticles (10-100 nm) as heterogeneous catalysts were synthesized and then immobilized onto cross-linked polymer carriers that are able to swell in aqueous media in order to increase photocatalytic activity to the highest level. It has been seen that the removal of textile dyes is possible by means of nanoparticles immobilized onto cross-linked polymer carriers. The performance of photocatalyst was evaluated in the removal of reactive textile dye (Acid Red 14) from aqueous media.

Improved dye entrapment–liberation performance at electrochemically synthesised polypyrrole–reduced graphene oxide nanocomposite films

In this work, we have reported the application of electropolymerised polypyrrole–reduced graphene oxide (Ppy–RGO) nanocomposite films as an effective tool for entrapping and liberating the model dye Acid Red 1, and thereby proposed this as an ecofriendly treatment for dye-containing textile effluents. Initially, a polypyrrole–graphene oxide (Ppy–GO) nanocomposite film was anodically synthesised by an in situ electropolymerisation of pyrrole and GO. The Ppy–GO film was then electrochemically reduced to form a Ppy–RGO nanocomposite film. The synthesised nanocomposite films were characterised by spectroscopy, microscopy, surface analysis and thermogravimetry. Brunauer, Emmett and Teller surface area analysis showed a 7.4-fold increase in surface area of Ppy–RGO films compared to that of $${\text{NO}}_{3}^{ - }$$ -polypyrrole films. In addition, based on tensile strength, Ppy–RGO films were demonstrated to be 12.7-folds mechanically stronger than $${\text{NO}}_{3}^{ - }$$ –Ppy films. When Acid Red 1 was entrapped in these films, an entrapment efficiency of as high as 95% for Acid Red 1 was achieved at Ppy–RGO films, which is significantly higher than 56% achieved at Ppy films. Similarly, while liberating the entrapped Acid Red 1 from the Ppy–RGO nanocomposite films, a liberation efficiency of 73% was estimated compared to 36% from the Ppy films.

Interaction between azo dye Acid Red 14 and pepsin by multispectral methods and docking studies.

The interaction of synthetic azo dye Acid Red 14 with pepsin was studied by fluorescence spectroscopy, UV-vis spectroscopy, circular dichroism and molecular docking. Results from the fluorescence spectroscopy show that Acid Red 14 has a strong capability to quench the intrinsic fluorescence of pepsin with static quenching. Binding constant, number of the binding sites and thermodynamic parameters were measured at different temperatures. The result indicates that Acid Red 14 interact with pepsin spontaneously by hydrogen bonding and van der Waals interactions. Three-dimensional fluorescence spectra and circular dichroism spectra reveal that Acid Red 14 could slightly change the structure of pepsin. The hydrogen bond is formed between Acid Red 14 and Tyr-189 and Thr-218 residues of pepsin. Furthermore, the binding between Acid Red 14 and pepsin inhibits pepsin activity. The study can provide a way to analyze the biological safety of Acid Red 14 on digestive proteases or other proteins.