scholarly journals Optimized Degradation of Bisphenol A by UV/H2O2 coupled to Microwaves in a Novel Reactional Setup

2021 ◽  
Author(s):  
Pedro Barrenha ◽  
Eduardo Bessa Azevedo
Keyword(s):  
Bisphenol A ◽  
Thermal Effects ◽  
Degradation Rate ◽  
Optimal Conditions ◽  
Residual Concentration ◽  
Environmental Concentration ◽  
First Order ◽  
Pseudo First Order ◽  
Mw Irradiation ◽  
Microwave Process

Abstract In this paper, the UV/H2O2/MW (microwave) process was compared with the UV/H2O2 one, using bisphenol A (BPA) as a model-pollutant. The proposed experimental setup was operated in batch recycle mode and allows for the direct comparison among different processes: UV only, H2O2 only, MW only, UV/H2O2, UV/MW, H2O2/MW, and UV/H2O2/MW, as well as temperature control to minimize thermal effects. The degradation of BPA at near-environmental concentration (100 µg L−1) was optimized by an experimental design approach (Response Surface Methodology) and its residual concentration was measured by HPLC. Approximately 95% of the initial BPA amount could be removed in 30 min at the optimal conditions (CH2O2 = 20 mg L−1, flow rate = 700 mL min−1, and MW power = 245 W). The experiments designed for comparing the UV/H2O2 and the UV/H2O2/MW processes showed that the use of MW doubled the initial pseudo-first-order degradation rate (from 0.046 to 0.10 min−1) and significantly increased the maximum oxidation capacity of the system (from 86 to 100%). Although the reasons behind those results are still unclear, it seems that the existence of non-thermal effects of the MW irradiation should be considered.

scholarly journals MW irradiation and ionic liquids as green tools in hydrolyses and alcoholyses

2020 ◽  
Vol 10 (1) ◽  
pp. 001-010 ◽  
Author(s):  
Nikoletta Harsági ◽  
Betti Szőllősi ◽  
Nóra Zsuzsa Kiss ◽  
György Keglevich
Keyword(s):  
Ionic Liquids ◽  
Alkaline Hydrolysis ◽  
Alkyl Group ◽  
Phosphinic Acid ◽  
Reaction Times ◽  
Alternative Possibility ◽  
First Order ◽  
Pseudo First Order ◽  
Mw Irradiation ◽  
Hydrolysis Of

Abstract The optimized HCl-catalyzed hydrolysis of alkyl diphenylphosphinates is described. The reaction times and pseudo-first-order rate constants suggested the iPr > Me > Et ∼ Pr ∼ Bu order of reactivity in respect of the alkyl group of the phosphinates. The MW-assisted p-toluenesulfonic acid (PTSA)-catalyzed variation means a better alternative possibility due to the shorter reaction times, and the alkaline hydrolysis is another option. The transesterification of alkyl diphenylphosphinates took place only in the presence of suitable ionic liquids, such as butyl-methylimidazolium hexafluorophosphorate ([bmim][PF6]) and butyl-methylimidazolium tetrafluoroborate ([bmim][BF4]). The application of ethyl-methylimidazolium hydrosulfate ([emim][HSO4]) and butyl-methylimidazolium chloride ([bmim][Cl]) was not too efficient, as the formation of the ester was accompanied by the fission of the O–C bond resulting in the formation of Ph2P(O)OH. This surprising transformation may be utilized in the phosphinate → phosphinic acid conversion.

scholarly journals Photocatalytic Degradation of Organic Dyes by H4SiW6Mo6O40/SiO2Sensitized by H2O2

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Li Yu ◽  
Yongkui Huang ◽  
Yun Yang ◽  
Yulin Xu ◽  
Guohong Wang ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Organic Dyes ◽  
Irradiation Time ◽  
Order Kinetic ◽  
Optimal Conditions ◽  
Basic Fuchsin ◽  
First Order ◽  
Degradation Of Dyes ◽  
Order Kinetic Model ◽  
Catalyst Dosage

H4SiW6Mo6O40/SiO2was sensitized by H2O2solution that significantly improved its catalytic activity under simulated natural light. Degradation of basic fuchsin was used as a probe reaction to explore the influencing factors on the photodegradation reaction. The results showed that the optimal conditions were as follows: initial concentration of basic fuchsin 8 mg/L, pH 2.5, catalyst dosage 4 g/L, and light irradiation time 4 h. Under these conditions, the degradation rate of basic fuchsin is 98%. The reaction of photocatalysis for basic fuchsin can be expressed as the first-order kinetic model. After being used continuously for four times, the catalyst kept the inherent photocatalytic activity for degradation of dyes. The photodegradation of malachite green, methyl orange, methylene blue, and rhodamine B were also tested, and the degradation rate of dyes can reach 90%–98%.

Preparation of Bead-on-String Nanofibers and its Application for the Removal of Bisphenol A

2015 ◽  
Vol 814 ◽  
pp. 125-131
Author(s):  
Fang Qiu ◽  
Min Le Peng ◽  
Zhi Mei Wei ◽  
Gang Zhang ◽  
Sheng Ru Long ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Bisphenol A ◽  
Kinetic Data ◽  
Processing Parameters ◽  
Order Kinetic ◽  
Average Width ◽  
First Order ◽  
Pseudo Second Order ◽  
Pseudo First Order ◽  
Adsorption Desorption

Bead-on-string nanofibers were prepared by electrospinning, in this work, . The effect of processing parameters and property of solutions on the morphology of bead-on-string nanofibers were systematically investigated. The results revealed that the morphology of beads on nanofibers transformed from spherical into spindle-like with increased concentration of solution, applied voltage and needle-collector distance. Average width of beads became smaller as increasing all the values of processing parameters. Meanwhile, the application for the removal of bisphenol A (BPA) from aqueous solution was investigated, and results showed that the bead-on-string nanofibers could effectively remove BPA from aqueous solution. The kinetic data were analyzed by the pseudo-first-order, pseudo-second-order kinetic models. The reusability of the composite nanofiber was also determined after five adsorption–desorption cycles.

Degradation Kinetics of Reactive Brilliant Red X-3B Dye by UV/Mn2+/H2O2/Micro-Aeration

2012 ◽  
Vol 441 ◽  
pp. 549-554
Author(s):  
Ying Jie Cai ◽  
Xiao Jun Yang ◽  
Dong Sheng Xia ◽  
Qing Fu Zeng
Keyword(s):  
Degradation Rate ◽  
Ph Value ◽  
Degradation Kinetics ◽  
H2o2 Concentration ◽  
Kinetics Equation ◽  
Linear Least Squares ◽  
First Order ◽  
First Order Kinetics ◽  
Pseudo First Order ◽  
Kinetics Of

Abstract. Degradation of reactive brilliant red X-3B (X-3B) by a UV/Mn2+/H2O2/micro- aeration method was investigated. The influencing factors of degradation of X-3B including UV irradiation, aeration, pH value, H2O2 concentration and X-3B concentration were examined. The results show that X-3B was effectively degraded by the UV/Mn2+/H2O2/micro-aeration method. The degradation rate of X-3B was obtained from weighted linear least squares analysis of the experimental data, and accorded with the pseudo-first order kinetics equation.

scholarly journals Ampicillin removal by adsorption onto activated carbon: kinetics, equilibrium and thermodynamics

2019 ◽  
Vol 79 (10) ◽  
pp. 2013-2021 ◽  
Author(s):  
Paola Del Vecchio ◽  
Nathalia K. Haro ◽  
Fernanda Siqueira Souza ◽  
Nilson Romeu Marcílio ◽  
Liliana A. Féris
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Contact Time ◽  
Bacterial Resistance ◽  
Aquatic Organisms ◽  
Batch Adsorption ◽  
Phase Contact Time ◽  
Residual Concentration ◽  
First Order ◽  
Pseudo First Order

Abstract Pharmaceutical compounds are essential to preserve human and animal welfare, as well as to prevent illnesses. However, the elevated consumption of drugs, followed by incorrect disposal and inefficient wastewater treatment, may increase their environmental risk. In the case of antibiotics, such as ampicillin, some of the already known consequences are bacterial resistance and some toxic interactions with aquatic organisms. The scope of the present work is to investigate the removal of ampicillin through batch adsorption experiments onto granular activated carbon (GAC). The influence of pH and phase contact time were evaluated. Pseudo-first order, pseudo-second order and intraparticle diffusion models were adjusted to experimental data to determine process kinetics. In order to study adsorption equilibrium and thermodynamics parameters, isotherms at 298 K, 298 K and 308 K were constructed. The models of Langmuir, Freundlich and Sips fitted to experimental data. The best results (73% of removal, residual concentration 5.2 mg L−1) were reached at pH 6 and 120 minutes of contact time. Pseudo-first order model better represented the adsorption kinetics (R2 = 0.99), while the Langmuir equation suited well the experimental isotherms at 288 K and 298 K (R2 = 0.998 and R2 = 0.991) and the Sips equation better represented the system at 308 K (R2 = 0.990). Thermodynamic parameters were estimated as ΔG° = −6,000 J mol−1; −6,700 J mol−1; −7,500 J mol−1 at 288 K, 298 K and 308 K respectively, ΔH° = 14,500 J mol−1 and ΔS° = 71.0 J mol−1 K−1. The results indicate that this process is spontaneous, efficient and potentially applicable in the removal of ampicillin from water.

Preparation of Iodine Doped Titanium Dioxide to Degrade Aqueous Bisphenol A

2014 ◽  
Vol 595 ◽  
pp. 14-18
Author(s):  
Chao Yin Kuo ◽  
Hung Min Hsiao ◽  
Xiang Ren Lin
Keyword(s):  
Titanium Dioxide ◽  
Bisphenol A ◽  
Uv Light ◽  
Removal Rate ◽  
First Order ◽  
First Order Kinetics ◽  
Pseudo First Order ◽  
Doped Titanium Dioxide ◽  
The Stability ◽  
Degradation Effect

Degradation of aqueous bisphenol A (BPA) using photocatalysts of granular iodine doped titanium dioxide (I-doped TiO2) under various irradiations (365 or 410 nm) was investigated. The degradation effect of aqueous BPA using I-doped TiO2 photocatalysts (iodine/titanium = 0.5 mole %) were 93 and 100 % under two irradiations of visible and UV light. This result indicated that I-doped TiO2 photocatalysts of were achieving energy-saving. In addition, the BPA removal rate satisfies pseudo-first-order kinetics and the degradation of BPA was evident after five cycles, indicating the stability and reusability.

scholarly journals Nano-Catalytic Ozonation of 4-Nitrochlorobenzene in Aqueous Solutions

2012 ◽  
Vol 9 (4) ◽  
pp. 1968-1975 ◽  
Author(s):  
S. M. Tabatabaei ◽  
A. Mehrizad ◽  
P. Gharbani
Keyword(s):  
Particle Size ◽  
Degradation Rate ◽  
Batch Reactor ◽  
Kinetic Studies ◽  
Catalytic Ozonation ◽  
Main Role ◽  
Order Kinetic ◽  
Nano Zno ◽  
First Order ◽  
Pseudo First Order

In this paper, efficiency of nano-ZnO particles on catalytic ozonation of 4-nitrochlorobenzene (4NCB) using semi-batch reactor has been studied at various pHs. During the catalytic ozonation, TOC and concentration of nitrate ions was monitored. Results indicate that degradation of 4NCB was improved by combination of nano-ZnO with ozone. The effect of ZnO particle size and pH are also examined. According to the results, concentration of 4NCB decreased with increasing of particle size from nanosized to microsized and pH from 3.0 to 9.0. Based on the results, it suggests radical hydroxyl does not affect on the degradation of 4NCB in catalytic ozonation, but the surface of catalyst plays main role. Kinetic studies showed degradation of 4NCB followed pseudo-first-order kinetic and maximum degradation rate was observed at pH=3.

Photodegradation of sulfonamide antimicrobial compounds (sulfadiazine, sulfamethizole, sulfamethoxazole and sulfathiazole) in various UV/oxidant systems

2015 ◽  
Vol 71 (3) ◽  
pp. 412-417 ◽  
Author(s):  
J. T. Wu ◽  
C. H. Wu ◽  
C. Y. Liu ◽  
W. J. Huang
Keyword(s):  
Degradation Rate ◽  
Removal Rate ◽  
Antimicrobial Compounds ◽  
Mineralization Rate ◽  
First Order ◽  
First Order Kinetics ◽  
Photodegradation Rate ◽  
Total Organic Carbon Removal ◽  
Pseudo First Order ◽  
H2o2 System

This study used Na2S2O8, NaBrO8 and H2O2 to degrade sulfadiazine (SDZ), sulfamethizole (SFZ), sulfamethoxazole (SMX) and sulfathiazole (STZ) under ultraviolet (UV) irradiation. The initial concentration of sulfonamide and oxidant in all experiments was 20 mg/L and 5 mM, respectively. The degradation rate for sulfonamides satisfies pseudo-first-order kinetics in all UV/oxidant systems. The highest degradation rate for SDZ, SFZ, SMX and STZ was in the UV/Na2S2O8, UV/NaBrO3, UV/Na2S2O8 and UV/H2O2 system, respectively. In the UV/Na2S2O8 system, the photodegradation rate of SDZ, SFZ, SMX and STZ was 0.0245 min−1, 0.0096 min−1, 0.0283 min−1 and 0.0141 min−1, respectively; moreover, for the total organic carbon removal rate for SDZ, SFZ, SMX and STZ it was 0.0057 min−1, 0.0081 min−1, 0.0130 min−1 and 0.0106 min−1, respectively. Experimental results indicate that the ability of oxidants to degrade sulfonamide varied with pollutant type. Moreover, UV/Na2S2O8 had the highest mineralization rate for all tested sulfonamides.

Studies on the reaction mechanism of Cu/SiC catalytic oxidation for degradation of methyl orange in presence of microwave

2019 ◽  
Vol 79 (6) ◽  
pp. 1164-1173 ◽  
Author(s):  
Guotong Xia ◽  
Jie Sun ◽  
Wenjin Yang ◽  
Gao-Lin Wu ◽  
Weibo Shen
Keyword(s):  
Hydrogen Peroxide ◽  
Methyl Orange ◽  
Hydroxyl Radicals ◽  
Impregnation Method ◽  
First Order ◽  
Pseudo First Order ◽  
Mw Irradiation ◽  
Catalyst Dosage ◽  
Degradation Of Methyl Orange ◽  
H2o2 System

Abstract The removal of methyl orange (MO) in a copper-loaded silicon carbide (Cu/SiC) system under microwave (MW) irradiation was studied. Cu/SiC was synthesized by employing an impregnation method and the effects of parameters such as reaction time, catalyst dosage, hydrogen peroxide (H2O2) dosage, microwave power and pH on the rate of degradation of MO were also studied. The obtained results showed that almost complete degradation was obtained in the presence of Cu/SiC catalyst within 8 min of irradiation when 100 mL of MO solution (20 mg/L), 3 ml/L of H2O2, 2 g/L of catalyst dose, 600 W of MW power, and pH 7 were applied. The Cu-bearing catalyst with H2O2 formed a Fenton-like system and the rate of generation of hydroxyl radicals (·OH) was also accelerated by subjecting to MW. From the kinetic analysis, it is revealed that the degradation of MO using the MW-Cu/SiC-H2O2 system follows the pseudo-first-order.

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