Blue Removal Research Articles

Reusable Halophilic Bacteria Attached Cellulose Acetate Nanofiber Webs for Removal of Cr (VI) and Reactive Dye

Hexavalent Chromium (Cr (VI)) and Reactive Blue (RB) removal efficiencies of halotolerant Citricoccus sp. were examined for different parameters such as initial pH, contact time, temperature static/shaking, NaCl concentration, and different pollutant concentrations. In this research, Citricoccus sp. attached cellulose acetate (CA) nanofiber webs (NfW) were produced by electrospinning method to improve the removal yield even further. The Cr (VI) removal yield was calculated as 11.39 ± 0.002% for the pristine CA-NfW, whereas it was 39.19 ± 0.43% for bacteria attached CA-NfW. Therefore, the Cr (VI) removal capacities of bacteria attached CA-NfW were significantly higher than that of pristine CA-NfW. In addition, reusability tests revealed that bacteria attached CA-NfW can be used at least three successive times in decolorization and Cr (VI) removal steps. The decolorization rate of the RB and Cr (VI) removal yield was found to be 31.5 ± 0.2% and 5.63 ± 0.30%, respectively. These results are promising and therefore suggest that bacteria attached CA-NfW could be applicable for the removal of wastewater containing Cr (VI) and reactive dye due to their versatility and reusability.

Preparation and Characterization of Eco-friendly Nanocomposite for Methylene Blue Dye Removal from Industrial Wastewater

Preparation and Characterization of Eco-friendly Nanocomposite for Methylene Blue Dye Removal from Industrial Wastewater

Role of Point of Zero Charge in the Adsorption of Cationic Textile Dye on Standard Biochars from Aqueous Solutions: Selection Criteria and Performance Assessment

The point of zero charge (PZC) is an inherent electrokinetic property of biochars (BC). It influences the adsorption process under certain pH conditions. Herein, we report the method of determination of the PZC values of ten standard BCs. We used the salt addition method to select the BCs with suitable properties for methylene blue (MB) removal from aqueous solutions. The standard BCs were obtained by pyrolyzing five different biomasses at two distinct temperatures (550°C and 700°C). The BCs derived from rice husk (pHPZC at 7.22 and 7.64 for RH550 and RH700, respectively) and softwood pellets (pHPZC at 6.57 and 6.78 for SWP500 and SWP700, respectively) were selected for their compatibility with cationic dyes such as MB. Results from adsorption experiments indicated the potential use of the RH biochar as an adsorbent for the removal of MB from aqueous solutions. The removal efficiencies were 68.83% and 71.97% for RH550 and RH700, respectively. Considerably low values were obtained for SWP550 and SWP700 (21.61% and 22.84%, respectively). Equilibrium was achieved at 2 h for RH550 and 1 h for RH700, and the adsorption kinetics for the RH BCs could be described by a pseudo-second order equation. The results revealed that even when produced under comparable conditions, BCs obtained from different feedstocks exhibited different cationic dye removing abilities. BCs optimized for the removal of cationic or anionic dyes can be easily engineered by appropriately matching the feedstock with the processing conditions.

Equilibrium and kinetics of sorption and resorption of acid and basic dyes using the pulp of carob pods

Being an abundant product in Algeria, pulp of carob pods (PCP) was used in this study as a biosorbent for Methylene blue (MB) and Congo red (CR) removal from aqueous media in batch mode in two successive steps. Once the first dye is adsorbed, the biosorbent is used as is to adsorb the second dye in order to study the interactions between them. Characterization of PCP by FTIR spectroscopy, Scanning Electron Microscopy (SEM), EDX, and point of zero charge showed that the principal functional groups present at the surface are oxygenated with a pHpzc value of the 7.2. Contact time of 60 min was amply sufficient to reach equilibrium for both dyes onto PCP and recuperated biosorbents. pH effect on the biosorption onto PCP shows a behavioral divergence between both dyes. Maximum biosorption uptake of CR was observed at pH value of 6.38 while pH variation has no remarkable influence on MB biosorption and the initial pH solution of 5.75 was taken for subsequent biosorption experiments. The adsorption isotherms obtained are in good agreement with the models of Langmuir and Freundlich and the kinetics are well described by the pseudo-second-order model.

Peracetic Acid Activated with Electro-Fe2+ Process for Dye Removal in Water

An electro-Fe2+-activated peracetic acid (EC/Fe2+/PAA) process was established for organic dye removal in water. The operation factors such as the PAA dosage, Fe2+ amount, current density, and pH were investigated on methylene blue (MB) removal for the synergistic EC/Fe2+/PAA system. Efficient MB decolorization (98.97% and 0.06992 min−1) was achieved within 30 min under 5.4 mmol L−1 PAA, 30 μmol L−1 Fe2+, 15 mA cm−2 current intensity, and pH 2.9. Masking tests affirmed that the dominating radicals were hydroxyl radicals (OH), organic radicals (CH3CO2·, CH3CO3·), and singlet oxygen (1O2), which were generated from the activated PAA by the synergetic effect of EC and Fe2+. The influence of inorganic ions and natural organic matter on the MB removal was determined. Moreover, the efficacy of the EC/Fe2+/PAA was confirmed by decontaminating other organic pollutants, such as antibiotic tetracycline and metronidazole. The studied synergy process offers a novel, advanced oxidation method for PAA activation and organic wastewater treatment.

Methylene Blue Cationic Dye Removal using AA-Am Hydrogel as An Efficient Adsorbent

Methylene Blue Cationic Dye Removal using AA-Am Hydrogel as An Efficient Adsorbent

Investigation of adsorption performances of green walnut hulls for the removal of methylene blue

Investigation of adsorption performances of green walnut hulls for the removal of methylene blue

Carbonized propagation synthesis of porous CQDs–SrTiO3/graphene and its photocatalytic performance for removal of methylene blue

Photocatalytic removal of methylene blue by the CQDs–SrTiO3/graphene material (CSG-5) under simulated visible light.

Comparative Study on Removal Efficiency of Methylene Blue from Wastewater by using Nano-Scaled Sugarcane Bagasse Ash and Jema Silica Sand

The widely available and easily accessible natural resources are very important to remove organic dyes from wastewater. Here in this work, Methyele Blue (MB) removal efficiency of Jemma Silica Sand (JSS) and Sugar Cane Bagasse ash (SCBA) from aqueous solutions was investigated. The XRD patterns revealed that both JSS and SCBA are crystalline, but the crystalline size of JSS is 56.27 nm and that of SCBA is 70.90 nm. In addition to the percentage of silicon dioxide in JSS was 98% and in that of SCBA was 71.5% as confirmed by XRF results. The morphology and elemental composition of the two materials were revealed by SEM and EDX. The MB removal efficiency of SCBA (~99.14%) is greater than that of JSS (~93.75) because of its higher porosities nature. The adsorption of MB by SCBA follows the Freundlich isotherm model and pseudo-second-order kinetic model indicating chemisorption. Therefore, SCBA is promising absorbent for removing MB from wastewater because of its efficient, cost-effectiveness, and environmentally friendly nature.

Optimization and biosynthesis of calcined chicken eggshell doped titanium dioxide photocatalyst based nanoparticles for wastewater treatment

This study presents, biosynthesis of calcinated eggshell (CES) doped with Titanium dioxide (TiO2,) photocatalyst for photodegradation of methylene blue from synthetic wastewater. The influence of three independent variables for improving photodegradation efficiency was investigated and optimized using response surface methodology of Box–Behnken Design on the removal of methylene blue using the calcined chicken eggshells (CES) doped with titanium dioxide. The experimental result showed that 95.8% degradation efficiency of methylene blue by prepared photocatalyst at a contact time of 180 min, initial concentration of methylene blue of 10 ppm, and calcined eggshells (CES) doped with titanium dioxide dose of 2.5 g/L. The synthesized photocatalyst was characterized by Fourier-transform infrared spectroscopy, UV-spectrometer, and X-ray diffractometer and UV–vis Spectroscopy for determined their functional group, structure, and bandgap energy respectively. Their results depict the calcined eggshell doped with titanium dioxide photocatalyst is a promising option for the degradation of methylene blue from industrial wastewater under the stated condition.HighlightsAnalysis of chicken eggshell wastes are being used as photocatalyst source to calcinated eggshell doped TiO2, i.e., ‘Waste to photocatalyst’ for production of viable sustainable products to bio photocatalyst from wastewater to fulfill the need of an expensive metal-doped catalyst.Photocatalytic degradation of Methylene Blue experiment has been done.The highest degradation efficiency of 95.8% methylene blue was obtained at a contact time of 180 min, 10 ppm of initial concentration of methylene blue, and a dopant dose of 2.5 g/L by using prepared photocatalyst.

Adsorption Of Methylene Blue By Imperata Cylindrica: Reaction Optimization By Response Surface Methodology (RSM)

Imperata Cylindrica (IC) is a solid waste that is readily available throughout the year known as one of the most important weed in the world and frequently causes major disposal issues. As a result, using IC as a low-cost adsorbent is beneficial from both, economic and environmental standpoint to remove colors from wastewater of textile industry. This work studies the reaction optimization of methylene blue (MB) removal using IC by response surface methodology (RSM). The RSM experiments were designed with 4 independent variables (initial adsorbent dosage, initial pH, initial dye concentration, and initial temperature) and 1 response variable (percent removal of MB). According to the pareto figure, the initial pH demonstrated the greatest impact on the percent removal of MB. The RSM data predicted the optimum condition of MB removal up to 86.61% using IC, by utilizing adsorbent dosage of 1.458 g/L, at 42 oC, initial pH of 6.8 and MB concentration of 235 ppm. The chacterization analysis revealed the physicochemical properties of IC in the adsoprtion process.

Rapid Removal of Methylene Blue in Water Using Polymer-Based Biochar Nanocomposite-Coated Filters

In this study, the effectiveness of novel nanocomposite-coated filters consisting of biochar (BC) functionalized with sodium alginate (SA) and poly (vinyl alcohol) (PVA) was investigated for methylene (MB) blue removal. The filters were fabricated via a dip-coating method and SEM and FTIR spectroscopy confirmed the successful coating of the filters. The impact of the nanocomposite formulation and the operating parameters (initial pH and MB concentration) on the performance of the coated filters were studied. A nanocomposite composition consisting of 1.0 wt.% SA, 2.0 wt.% PVA, and 1000 ppm BC were found to be optimum, reaching as high as 96.51% MB removal. The fabricated filters were determined to be robust over a wide range of pH and initial MB concentrations. The Sips isotherm model proved to be the best-fit model for MB adsorption, where chemisorption dominates at low MB concentrations, while physisorption dominates at high MB concentrations. The filters have a maximum sorption capacity of 54.5198 mg g-1 and showed good reusability. Overall, our synthesized SA/PVA/BC-coated filters can be used to effectively remove dyes in wastewater over a wide range of operating conditions.

Luminescent, sorptive and antibacterial potential of bismuth-organic framework

Metal organic frameworks are formed by the three-dimensional linkage of metal cores and organic linkers. In this work, bismuth-based metal organic framework (Bi-MOF) has been synthesized by using 5-hydroxyisophthalic acid (H2HIA) as linker via hydrothermal method. The said MOF was structurally characterized by UV/Vis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), 1H NMR, energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA) and X-ray diffraction technique. This MOF showed highly porous structure with surface area 1096 m2/g as determined by BET analysis. A model batch adsorption experiment was performed to evaluate the efficiency of methylene blue (MB) dye removal from aqueous media. It was found that monolayer adsorption capacity calculated from the Langmuir isotherm was 0.6240 mg/g. Bi-MOF was also screened for its antibacterial and luminescent behavior.
 
 KEY WORDS: Bismuth, Metal-organic Frameworks, Luminescence, Sorption
 
 Bull. Chem. Soc. Ethiop. 2021, 35(1), 119-128.
 DOI: https://dx.doi.org/10.4314/bcse.v35i1.10

Optimization of Swiss blue dye removal by cotton boll activated carbon: response surface methodological approach

Cotton boll activated carbon (CBAC) was employed for Swiss blue (SB) decolorization from simulated wastewater. Adsorption data conformed better with Langmuir adsorption isotherm with highest adsorption capability of 52.631 mg g−1. Swiss blue adsorption onto CBAC was thermodynamically spontaneous and can be ascribed to follow the pseudo second order (PSO) kinetic model. An experimental matrix based on Box–Behnken design (BBD) of response surface methodology (RSM) was used to design the batch experiments for investigating the adsorption of SB onto CBAC considering four operating factors, viz. initial pH (2–12), contact time (15–150 min), SB concentration (125–375 mg L–1) and CBAC dose (0.2–1 g/100 mL). RSM-BBD worked successfully to model the process, optimize the factors, and predict SB removal.

Enhancing methylene blue sorption on spotted golden thistle stalks by soft chemical pretreatments

Soft chemical treatments of dried stalks of the spotted golden thistle yielded novel sorbents; both the stiff nature and mass of the raw material were preserved. For minimal environment impact, the solution concentrations of the tested reagents were optimized at ambient temperature. The sorbents obtained were tested for the removal of methylene blue. The approach used kinetics and equilibrium studies. NaOH (0.1 mol L−1) treatment was efficient and afforded two new materials with seriously improved sorption features: the equilibrium time was reduced from 17–19 h to 10–12 h whilst, maximal sorption capacity increases from 65 to 100 and 112 mg g−1 i.e., enhancements of 54 and 72%. The Avrami model followed by the pseudo second-order model, best fitted the kinetic data. The isotherms were of Hmx type and were satisfactorily fitted to the Redlich-Peterson model. The Langmuir, Tóth, and Sips models were suitable to describe the H type isotherms relating to limited data ranges. Microanalysis, scanning electron microscopy (SEM), SEM coupled to energy dispersive X-ray, and attenuated total reflectance infrared spectroscopy showed an increase of the lignocellulosic content and the strengthening of the interactions between the dye and the sorbent. However, zeta potential measurements showed that the charge of the surface became almost inexistent after the pretreatment.

Effect of synthesis method of LaNiO3 type materials with perovskite structure on their features and in the methylene blue dye removal from aqueous media

Oxides with perovskite structure are the target of important studies, as they are versatile materials that have shown magnetic, electrical, optical, catalytic, adsorptive applications, among others, and are also easily synthesized. These applications are potentially influenced by the synthesis method, and in this sense, several methods have been used to prepare these materials, in order to optimize their characteristics and properties. The methods: modified protein using gelatin as a complexing agent, mechanosynthesis and combustion method in the heating plate and microwave were used to prepare LaNiO3 type materials with perovskite structure used in the present work. The materials obtained were characterized by physical-chemical techniques (X-ray diffraction, nitrogen adsorption at 77 K and determination of the point of zero charge) and evaluated as an adsorbent for the removal of methylene blue dye in aqueous medium. All materials showed potential for removing the dye from the medium, with emphasis on the material obtained by mechanosynthesis, which presented higher methylene blue dye discoloration efficiency, due its smaller crystallite size and larger surface area. After the dye removal tests, the perovskite structure was preserved and the adsorbent was reused after being subjected to calcination at 900 °C for 2 hours when simultaneous degradation of the previously adsorbed dye occurred. The reused materials still had a high potential for dye removal.

Fe-doped carbon aerogels from sodium alginate for the removal of methylene blue

In this article, Fe-doped carbon aerogels from sodium alginate were used for the removal of methylene blue (MB) in water. Under acidic condition, the sample carbonized at 700 °C (T700) undergoes Fe-C micro-electrolysis to produce highly chemically active Fe2+ and [H] to degrade MB. Under neutral or alkaline conditions, Fe2+ produced by Fe-C micro-electrolysis become Fe(OH)3, which can effectively adsorb MB. In addition, when T700 combines with H2O2 to form Fenton system, the MB removal efficiency was significantly improved. The Fe-doped carbon aerogels can be used in wastewater treatment and when combine the materials with H2O2 can greatly improve the MB removal efficiency.

Dyes adsorption properties of KOH-activated resorcinol-formaldehyde carbon gels -kinetic, isotherm and dynamic studies

This work was aimed to evaluate the adsorption properties of KOH-activated resorcinol-formaldehyde carbon gels for cationic methylene blue and anionic congo red removal from water. The activated carbons were characterized for surface chemistry and textural properties. The surface area of 427 m2/g and 433 m2/g were obtained for resorcinol-to-catalyst ratios of 100 and 2000, respectively. The carbon gels demonstrate a site-selective adsorption, where the maximum methylene blue capacity is 135 mg/g, while that of congo red is 16 mg/g. The equilibrium data fitted well with Langmuir model, where the adsorption could be described as a hybrid of physical-chemical process controlled by film diffusion. The dynamic data also support that the kinetics was controlled by external mass transfer or film diffusion for suitable application in dye wastewater treatment.

A novel flower-like MnO2 nanowires for rapid removal of methylene blue

In order to enhance the adsorption property of adsorbent, surface modification of existing adsorption materials has always been an interesting and challenging topic. Herein, the flower-like MnO2 nanowires (MNs) with three dimensions surface area and great adsorption property was successfully prepared by two-step hydrothermal route via MnO2 nanosheets in-situ growth on MnO2 nanowires. As an adsorbent, the MNs was evaluated for the removal of methylene blue (MB) from the aqueous solution. The effect of pH value, contact time, adsorbent dose, adsorption equilibrium, kinetics adsorption process, and isothermal models was investigated. The results showed that the maximum adsorption capacity of MNs of 2 g/L attained 34.247 mg/g at 5 minutes, and kinetics of MB were found fitting using the Langmuir model and the pseudo-first-order model, respectively. Furthermore, the adsorption capacity can be kept over 90% after five adsorption cycles. Therefore, the composite material can be a promising tool for developing a large variety of efficient and stable adsorbents by combining with different nanostructures for dyeing wastewater treatment.

Effect of ionic strength on methylene blue sorption onto macroporous resins: a comprehensive study

In the current study, adsorption behaviors of amberlite XAD-7 and XAD-16 for the removal of methylene blue from its aqueous solutions have been reported with several respects. First, response surface approach (RSA) has been used to identify the optimum conditions (0.21 g resin/10 mL MTB solution under 149 rpm mixing speed of shaking bath) for the best adsorption process of methylene blue (MTB) removal (≈99%). The most significant process parameter was found to be solution volume, followed by resin amount and speed. Effects of fluoride and chloride on the MTB removal have been also investigated. Elevated concentration of ions in MTB solutions gave rise to decline the adsorption capacity regularly, while the adsorption yield enhanced by increase in pH. On the other hand, the concerned adsorption system was a chemisorption process based on the kinetic (pseudo-first order, pseudo-second order, intraparticle diffusion models) and equilibrium (Langmuir, Freundlich, Temkin, Dubinin–Radushkevich isotherm equations) parameters.