scholarly journals Application of Silver-Loaded Composite Track-Etched Membranes for Photocatalytic Decomposition of Methylene Blue under Visible Light

Membranes ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 60 ◽  
Author(s):  
Anastassiya A. Mashentseva ◽  
Murat Barsbay ◽  
Nurgulim A. Aimanova ◽  
Maxim V. Zdorovets
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Degradation Kinetics ◽  
Composite Membranes ◽  
Degradation Process ◽  
Decomposition Reaction ◽  
Photocatalytic Decomposition ◽  
Order Kinetic ◽  
Langmuir Hinshelwood Mechanism ◽  
Order Kinetic Model

In this study, the use of composite track-etched membranes (TeMs) based on polyethylene terephthalate (PET) and electrolessly deposited silver microtubes (MTs) for the decomposition of toxic phenothiazine cationic dye, methylene blue (MB), under visible light was investigated. The structure and composition of the composite membranes were elucidated by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction technique. Under visible light irradiation, composite membrane with embedded silver MTs (Ag/PET) displayed high photocatalytic efficiency. The effects of various parameters such as initial dye concentration, temperature, and sample exposure time on the photocatalytic degradation process were studied. The decomposition reaction of MB was found to follow the Langmuir–Hinshelwood mechanism and a pseudo-first-order kinetic model. The degradation kinetics of MB accelerated with increasing temperature and activation energy, Ea, was calculated to be 20.6 kJ/mol. The reusability of the catalyst was also investigated for 11 consecutive runs without any activation and regeneration procedures. The Ag/PET composite performed at high degradation efficiency of over 68% after 11 consecutive uses.

scholarly journals Thermal Stability and Degradation Kinetics of Patulin in Highly Acidic Conditions: Impact of Cysteine

Toxins ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 662
Author(s):  
Enjie Diao ◽  
Kun Ma ◽  
Hui Zhang ◽  
Peng Xie ◽  
Shiquan Qian ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Degradation Kinetics ◽  
Correlation Coefficients ◽  
Degradation Process ◽  
Weibull Model ◽  
Degradation Efficiency ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Acidic Conditions ◽  
Kinetics Of

The thermal stability and degradation kinetics of patulin (PAT, 10 μmol/L) in pH 3.5 of phosphoric-citric acid buffer solutions in the absence and presence of cysteine (CYS, 30 μmol/L) were investigated at temperatures ranging from 90 to 150 °C. The zero-, first-, and second-order models and the Weibull model were used to fit the degradation process of patulin. Both the first-order kinetic model and Weibull model better described the degradation of patulin in the presence of cysteine while it was complexed to simulate them in the absence of cysteine with various models at different temperatures based on the correlation coefficients (R2 > 0.90). At the same reaction time, cysteine and temperature significantly affected the degradation efficiency of patulin in highly acidic conditions (p < 0.01). The rate constants (kT) for patulin degradation with cysteine (0.0036–0.3200 μg/L·min) were far more than those of treatments without cysteine (0.0012–0.1614 μg/L·min), and the activation energy (Ea = 43.89 kJ/mol) was far less than that of treatment without cysteine (61.74 kJ/mol). Increasing temperature could obviously improve the degradation efficiency of patulin, regardless of the presence of cysteine. Thus, both cysteine and high temperature decreased the stability of patulin in highly acidic conditions and improved its degradation efficiency, which could be applied to guide the detoxification of patulin by cysteine in the juice processing industry.

scholarly journals Synthetic BiOBr/Bi2S3/CdS Crystalline Material and Its Degradation of Dye under Visible Light

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 899
Author(s):  
Yunhan Jin ◽  
Zhe Xing ◽  
Yinhui Li ◽  
Jian Han ◽  
Heike Lorenz ◽  
...  
Keyword(s):  
Composite Material ◽  
Visible Light ◽  
Dye Degradation ◽  
Degradation Process ◽  
Active Species ◽  
Order Kinetic ◽  
Test Results ◽  
Order Kinetic Model ◽  
Epr Test

Constructing heterojunction has attracted widespread concerns in photocatalysis research. BiOBr/Bi2S3/CdS composite material with a sea urchin shape was directly obtained by first synthesizing BiOBr microspheres. The morphology, structure and composition of the composite material were characterized by XRD, EDX, SEM and XPS. Dye degradation experiments showed that 83.3% of methylene blue removal was achieved after 2 h of visible light irradiation. The reaction rate under optimal conditions was 0.014 min−1 and the photocatalytic degradation process follows a pseudo-first-order kinetic model. Based on the EPR test results, the main active species involved in the reaction were •O2− and h+. The conduction band and valence band edge potential calculations confirmed the key role of CdS in the production of •O2−.

Photodegradation of microcystin-LR catalyzed by metal phthalocyanines immobilized on TiO2-SiO2 under visible-light irradiation

2015 ◽  
Vol 72 (10) ◽  
pp. 1824-1831 ◽  
Author(s):  
Guotao Peng ◽  
Zhengqiu Fan ◽  
Xiangrong Wang ◽  
Xin Sui ◽  
Chen Chen
Keyword(s):  
Visible Light ◽  
High Performance ◽  
Anatase Phase ◽  
Degradation Process ◽  
Visible Range ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Metal Phthalocyanines ◽  
Order Kinetic Model ◽  
Acute And Chronic Effects

Microcystins (MCs) are a group of monocyclic heptapeptide toxins produced by species of cyanobacteria. Since MCs exhibit acute and chronic effects on humans and wildlife by damaging the liver, they are of increasing concern worldwide. In this study, we investigated the ability of the phthalocyanine compound (ZnPc-TiO2-SiO2) to degrade microcystin-LR (MC-LR) in the presence of visible light. X-ray diffraction (XRD) and UV-Visible diffuse reflectance spectra (UV-Vis DRS) were utilized to characterize the crystalline phase and the absorption behavior of this catalyst. According to the results, XRD spectra of ZnPc-TiO2-SiO2 powders taken in the 2θ configuration exhibited the peaks characteristic of the anatase phase. UV-Vis DRS showed that the absorption band wavelength shifted to the visible range when ZnPc was supported on the surface of TiO2-SiO2. Subsequently, several parameters including catalyst dose, MC-LR concentrations and pH were investigated. The MC-LR was quantified in each sample through high-performance liquid chromatography (HPLC). The maximum MC-LR degradation rate of 80.2% can be obtained within 300 minutes under the following conditions: catalyst dose of 7.50 g/L, initial MC-LR concentration of 17.35 mg/L, pH 6.76 and the first cycling run of the photocatalytic reaction. Moreover, the degradation process fitted well with the pseudo-first-order kinetic model.

scholarly journals Fabrication of AgCl/Ag3PO4/graphitic carbon nitride heterojunctions for enhanced visible light photocatalytic decomposition of methylene blue, methylparaben and E. coli

RSC Advances ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 6383-6394 ◽  
Author(s):  
Haishuai Li ◽  
Linlin Cai ◽  
Xin Wang ◽  
Huixian Shi
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Visible Light Irradiation ◽  
Carbon Nitride ◽  
Light Irradiation ◽  
Graphitic Carbon Nitride ◽  
Photocatalytic Decomposition ◽  
E Coli ◽  
Visible Light Photocatalytic

A noval ternary nanocomposite AgCl/Ag3PO4/g-C3N4 was successfully synthesized for photocatalytic degradation of methylene blue, methylparaben and inactivation of E. coli under visible light irradiation, showing excellent photocatalytic degradation performance and stability.

scholarly journals Investigation of Seeds and Peels of Citrullus colocynthis as Efficient Natural Adsorbent for Methylene Blue Dye

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1279
Author(s):  
Wafa Mohammed Alghamdi ◽  
Ines El Mannoubi
Keyword(s):  
Methylene Blue ◽  
Kinetic Model ◽  
Langmuir Isotherm ◽  
Order Kinetic ◽  
Citrullus Colocynthis ◽  
Natural Adsorbent ◽  
Spontaneous Process ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Mb Adsorption

Natural adsorbents as low-cost materials have been proved efficient for water remediation and have significant capacity for the removal of certain chemicals from wastewater. The present investigation aimed to use Citrullus colocynthis seeds (CCSs) and peels (CCPs) as an efficient natural adsorbent for methylene blue (MB) dye in an aqueous solution. The examined biosorbents were characterized using surface area analyzer (BET), scanning electron microscope (SEM), thermogravimetric analyzer (TGA) and Fourier transform infra-red (FT-IR) spectroscopy. Batch adsorption experiments were conducted to optimize the main factors influencing the biosorption process. The equilibrium data for the adsorption of MB by CCSs were best described by the Langmuir isotherm followed by the Freundlich adsorption isotherms, while the equilibrium data for MB adsorption by CCPs were well fitted by the Langmuir isotherm followed by the Temkin isotherm. Under optimum conditions, the maximum biosorption capacity and removal efficiency were 18.832 mg g−1 and 98.00% for MB-CCSs and 4.480 mg g−1 and 91.43% for MB-CCPs. Kinetic studies revealed that MB adsorption onto CCSs obeys pseudo-first order kinetic model (K1 = 0.0274 min−1), while MB adsorption onto CCPs follows the pseudo-second order kinetic model (K2 = 0.0177 g mg−1 min−1). Thermodynamic studies revealed that the MB biosorption by CCSs was endothermic and a spontaneous process in nature associated with a rise in randomness, but the MB adsorption by CCPs was exothermic and a spontaneous process only at room temperature with a decline in disorder. Based on the obtained results, CCSs and CCPSs can be utilized as efficient, natural biosorbents, and CCSs is promising since it showed the highest removal percentage and adsorption capacity of MB dye.

scholarly journals Thermo-Analytical and Compatibility Study with Mechanistic Explanation of Degradation Kinetics of Ambroxol Hydrochloride Tablets under Non-Isothermal Conditions

Pharmaceutics ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1910
Author(s):  
Dijana Jelić ◽  
Snežana Papović ◽  
Milan Vraneš ◽  
Slobodan Gadžurić ◽  
Silvia Berto ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Active Compound ◽  
Degradation Kinetics ◽  
Practical Interest ◽  
Mechanistic Explanation ◽  
Compatibility Study ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Synthetic Derivative ◽  
Ambroxol Hydrochloride

Ambroxol hydrochloride (AMB), used as a broncho secretolytic and an expectorant drug, is a semi-synthetic derivative of vasicine obtained from the Indian shrub Adhatoda vasica. It is a metabolic product of bromhexine. The paper provides comprehensive and detailed research on ambroxol hydrochloride, gives information on thermal stability, the mechanism of AMB degradation, and data of practical interest for optimization of formulation that contains AMB as an active compound. Investigation on pure AMB and in commercial formulation Flavamed® tablet (FT), which contains AMB as an active compound, was performed systematically using thermal and spectroscopic methods, along with a sophisticated and practical statistical approach. AMB proved to be a heat-stable and humidity-sensitive drug. For its successful formulation, special attention should be addressed to excipients since it was found that polyvinyl pyrrolidone and Mg stearate affect the thermal stability of AMB. At the same time, lactose monohydrate contributes to faster degradation of AMB and change in decomposition mechanism. It was found that the n-th order kinetic model mechanistically best describes the decomposition process of pure AMB and in Flavamed® tablets.

scholarly journals Biosorption of Congo Red and Methylene Blue by pretreated waste Streptomyces fradiae biomass - Equilibrium, kinetic and thermodynamic studies

2018 ◽  
Vol 83 (1) ◽  
pp. 107-120 ◽  
Author(s):  
Zdravka Velkova ◽  
Gergana Kirova ◽  
Margarita Stoytcheva ◽  
Velizar Gochev
Keyword(s):  
Methylene Blue ◽  
Congo Red ◽  
Contact Time ◽  
Order Kinetic ◽  
Batch Experiments ◽  
Streptomyces Fradiae ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Kinetic And Thermodynamic Studies ◽  
Pretreated Biomass

Pretreated waste Streptomyces fradiae biomass was utilized as an eco-friendly sorbent for Congo Red (CR) and Methylene Blue (MB) removal from aqueous solutions. The biosorbent was characterized by Fourier transform infrared spectroscopy. Batch experiments were conducted to study the effect of pH, biosorbent dosage, initial concentration of adsorbates, contact time and temperature on the biosorption of the two dyes. The equilibrium adsorption data were analysed using Freundlich and Langmuir models. Both models fitted well the experimental data. The maximum biosorption capacity of the pretreated Streptomyces fradiae biomass was 46.64 mg g-1 for CR and 59.63 mg g-1 for MB, at a pH 6.0, with the contact time of 120 min, the biosorbent dosage of 2 g dm-3 and the temperature of 298 K. Lagergren and Ho kinetic models were used to analyse the kinetic data obtained from different batch experiments. The biosorption of both dyes followed better the pseudo-second order kinetic model. The calculated values for ?G, ?S, and ?H indicated that the biosorption of CR and MB onto the waste pretreated biomass was feasible, spontaneous, and exothermic in the selected temperature range and conditions.

scholarly journals Study on the adsorption of methylene blue from aqueous solution using hydrogel glucomannan/graphene oxide

2021 ◽  
Vol 10 (1) ◽  
pp. 59-66
Author(s):  
Son Le Lam ◽  
Phu Nguyen Vinh ◽  
Hieu Le Trung ◽  
Tan Le Thua ◽  
Nhan Dang Thi Thanh ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Graphene Oxide ◽  
Adsorption Capacity ◽  
Organic Dyes ◽  
Dye Adsorption ◽  
Order Kinetic ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Glucomannan/graphene oxide (GM/GO) hydrogel was synthesized by using calcium hydroxide as the crosslinker. The synthesized material was characterized by using IR, XRD, SEM, EDX and RAMAN technology. The composite hydrogel was used for removal of organic dyes from aqueous solution. The results showed that the GM/GO hydrogel had a porous structure and a high adsorption capacity toward methylene blue (MB). The pseudo-second-order kinetic model could fit the rate equation of MB adsorption onto the GM/GO hydrogel. The adsorption of MB onto GM/GO hydrogel was a spontaneous process. In addition, the equilibrium adsorption isotherm data indicated that equilibrium data were fitted to the Langmuir isotherm and the maximum dye adsorption capacity was 198,69 mg.g-1. Moreover, the hydrogel was stable and easily recovered and adsorption capacity was around 97% of the initial saturation adsorption capacity after being used five times.

scholarly journals Heterogeneous Fenton-Like Oxidation of Methylene Blue Using Alternative Catalysts

2021 ◽  
Vol 29 (48) ◽  
pp. 91-97
Author(s):  
Juraj Michálek ◽  
Kseniya Domnina ◽  
Veronika Kvorková ◽  
Kristína Šefčovičová ◽  
Klaudia Mončeková ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Methylene Blue ◽  
Low Cost ◽  
Hydrogen Peroxide Solution ◽  
Blue Dye ◽  
Order Kinetic ◽  
Heterogeneous Fenton ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Black Nickel

Abstract The usage of the low-cost catalysts for methylene blue removal from wastewater was investigated. Heterogeneous Fenton-like process consists of the use of a hydrogen peroxide solution, and an iron-rich catalyst, red mud and black nickel mud were used for that purpose. The factors such as the catalyst dose and the hydrogen peroxide solution volume were monitored. The results of experiments showed that the degradation of methylene blue dye in Fenton-like oxidation process using selected catalysts can be described by a pseudo-second-order kinetic model. The highest dye removal efficiency (87.15 %) was achieved using the black nickel mud catalyst after 30 minutes of reaction.

Photocatalytic Decomposition of Methylene Blue with Lanthanum Doping TiO2 under Visible Light Irradiation

2013 ◽  
Vol 734-737 ◽  
pp. 2163-2167
Author(s):  
Guang Xiu Cao ◽  
Zhong Hou Zhang ◽  
Bin Zhai
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
Light Irradiation ◽  
Photocatalytic Decomposition ◽  
Lanthanum Doping ◽  
X Ray ◽  
Degradation Rates ◽  
Vis Spectroscopy

Lanthanum doped TiO2 powders were prepared by hydrolysis of titanium tetra-n-butyl oxide and La (NO3)3 in solution. The resulting powders were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis absorption spectroscopy. The photocatalytic activities of doped samples were evaluated by the decomposition of methylene blue under visible light irradiation. The XRD results showed that the doping of lanthanum could not only efficiently inhibit the grain growth but also suppress the phase transition of anatase to rutile. UV-Vis spectroscopy of lanthanum doping TiO2 indicated that the absorption onset red-shifted to the visible light region. XPS results revealed that La2O3 had formed which could enhance the surface area. The degradation rates of methylene blue verified that the visible light photocatalytic activity of TiO2 has been enhanced by the doping of lanthanum.

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