Ferrate(VI): a novel oxidant for degradation of cationic surfactant – cetylpyridinium bromide

2013 ◽  
Vol 67 (10) ◽  
pp. 2184-2189 ◽  
Author(s):  
Weihua Yang ◽  
Xiaoyan Lin ◽  
Honghui Wang ◽  
Wutao Yang
Keyword(s):  
Reaction Time ◽  
Organic Carbon ◽  
Cationic Surfactants ◽  
Degradation Process ◽  
Order Kinetic ◽  
Cetylpyridinium Bromide ◽  
Operating Variables ◽  
Toc Removal ◽  
Treatment Conditions ◽  
Initial Ph

Ferrate(VI) is an efficient multi-functional water treatment reagent that has several novel properties, such as strong oxidation, absorption, flocculation, disinfection and deodorization. The removal of cationic surfactants based on ferrate (K2FeO4) was performed in the case of cetylpyridinium bromide (CPB). The influence of operating variables on the mineralization efficiency was studied as a function of ferrate dosage, initial pH and reaction time. Total organic carbon (TOC), UV and infrared spectra were performed to gain a better understanding of the degradation process. Results show that the optimal treatment conditions are as follows, solution initial pH is over 5, oxidation time is 5 min and ferrate dosage is 1.5 times that of CPB. The removal efficiency of CPB above 99% and TOC removal percentage of 91.3% can be achieved in minutes. The reaction of CPB with K2FeO4 responds to a second-order kinetic law.

scholarly journals Application of a Continuous Bipolar Mode Electrocoagulation (CBME) system for polishing distillery wastewater

2019 ◽  
Vol 93 ◽  
pp. 02005 ◽  
Author(s):  
Madhuri Damaraju ◽  
Debraj Bhattacharyya ◽  
Tarun Panda ◽  
Kiran Kumar Kurilla
Keyword(s):  
Reaction Time ◽  
Current Density ◽  
Optimal Point ◽  
Suitable Alternative ◽  
Toc Removal ◽  
Bipolar Mode ◽  
Recalcitrant Carbon ◽  
Initial Ph ◽  
Distillery Wastewater ◽  
Experimental Values

A continuous bipolar mode electrocoagulation (CBME) unit was used in this study for polishing a biologically treated distillery wastewater at laboratory scale. This study focuses on optimizing the process for removal of Total Organic Carbon (TOC) from an anaerobically-treated distillery wastewater. Response surface methodology (RSM) was used for optimizing the process. The study was conducted by varying three operating parameters: Initial pH (2-10), reaction time (0.5-15 min), and current density (13-40 A/sqm). High R-square values, above 0.9, were obtained with ANOVA. Optimal point was observed to be at pH-6.04, Reaction time-11.63 min, current density-39.2 A/sqm. Experimental values of TOC removal at optimal point were found to be 73% against maximum predicted value of 79%. Color removal efficiency was observed to be 85% at the optimal points. It can be concluded that CBME system can be a suitable alternative for removal of recalcitrant carbon and color post-biological treatment in distillery wastewaters.

scholarly journals Treatment of folic acid wastewater by 3D Fe-N-TiO2/AC photoelectrocatalysis system

2019 ◽  
Vol 80 (10) ◽  
pp. 1919-1930
Author(s):  
Junwo Zhou ◽  
Zhen Zhou ◽  
Yong Gao ◽  
Tingting Li ◽  
Manying Zhang ◽  
...  
Keyword(s):  
Folic Acid ◽  
Ph Value ◽  
Synergistic Effects ◽  
Three Dimensional ◽  
Degradation Process ◽  
Film Coating ◽  
Order Kinetic ◽  
Mechanism Study ◽  
Cellulose Acetate Film ◽  
Toc Removal

Abstract In this work, particles of activated carbon supported by Fe-N-TiO2 (Fe-N-TiO2/AC) were synthesized and used as the three-dimensional (3D) particle electrode for folic acid wastewater treatment in the 3D electrolysis and photocatalysis coupling process. The structure, morphology, and physical and electrochemical properties of the Fe-N-TiO2/AC particles were characterized, and the results showed that Fe-N-TiO2 was bound on the surface of AC particles by chemical attachment, and the Fe-N-TiO2/AC particles had better capability of adsorption and charge transfer as compared with the TiO2/AC particles. The effects of key operating parameters in the reaction process, including the current density (optimum 0.6 mA/cm2), aeration (optimum 5 L/min), pH value (optimum 5) and the ratio of Fe-N-TiO2/AC particles to cellulose acetate film coating AC particles (optimum 4:1), were optimized regarding the total oxygen carbon (TOC) removal. Under the optimum conditions, TOC removal from folic acid wastewater reached 82.4% during 120 min photoelectrocatalysis. The kinetic analysis and mechanism study showed that the degradation process fitted to the second-order kinetic model better than to the first-order, and the system exhibited synergistic effects in inhibiting photogenic electron–hole recombination and improving electrolytic efficiency. At the same time, this system has the ability to overcome the interference of the strong ionic strength in folic acid wastewater.

scholarly journals Biological Treatment of Wastewater from Pyrolysis Plant: Effect of Organics Concentration, pH and Temperature

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 336
Author(s):  
Luca Di Palma ◽  
Irene Bavasso ◽  
Mauro Capocelli ◽  
Paolo De Filippis ◽  
Vincenzo Piemonte
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Biological Treatment ◽  
Order Kinetic ◽  
Batch Mode ◽  
Mean Values ◽  
Wood Pyrolysis ◽  
Toc Removal ◽  
Order Kinetic Model ◽  
Different Temperatures

The biological treatment of the aqueous residue produced during poplar wood pyrolysis was investigated. The biological treatment experiments were carried out at two different pH conditions (controlled at 7, uncontrolled) in batch mode at three different temperatures (15 °C, 25 °C and 30 °C) and initial total organic carbon of the water ranging from 800 mg/L to 2800 mg/L. Results show that a substantial removal of organic carbon could be achieved in aerobic conditions after biomass acclimation. After 72 h of treatment, total organic carbon (TOC) removal mean values of 49.47% and 53.03% were observed at 30 °C for solution at 1400 and 2000 mg/L initial TOC, respectively. In the case of 1400 mg/L, a further mineralization (61.80%) was achieved during 144 h of treatment, by using a two-step process. A kinetic study of the process was also made, showing that organics mineralization followed a first-order kinetic model.

Treatment of tetrahydrofuran wastewater by the Fenton process: response surface methodology as an optimization tool

2014 ◽  
Vol 69 (5) ◽  
pp. 1080-1087 ◽  
Author(s):  
Xianzhong Cao ◽  
Huiqing Lou ◽  
Wei Wei ◽  
Lijuan Zhu
Keyword(s):  
Reaction Time ◽  
Response Surface ◽  
Removal Efficiency ◽  
Oxygen Demand ◽  
Treatment Method ◽  
Degradation Pathway ◽  
Fenton Process ◽  
Operating Variables ◽  
Rsm Optimization ◽  
Initial Ph

In this study, the Box-Benkhen design and response surface method (RSM) were applied to evaluate and optimize the operating variables during the treatment of tetrahydrofuran (THF) wastewater by Fenton process. The four factors investigated were initial pH, Fe2+ dosage, H2O2 dosage and reaction time. Statistical analysis showed the linear coefficients of the four factors and the interactive coefficients such as initial pH/Fe2+ dosage, initial pH/H2O2 dosage and Fe2+ dosage/H2O2 dosage all significantly affected the removal efficiency. The RSM optimization results demonstrated that the chemical oxygen demand (COD) removal efficiency could reach up to 47.8% when initial pH was 4.49, Fe2+ dosage was 2.52 mM, H2O2 dosage was 20 mM and reaction time was 110.3 min. Simultaneously, the biodegradability increased obviously after the treatment. The main intermediates of 2-hydroxytetrahydrofuran, γ-butyrolactone and 4-hydroxybutanoate were separated and identified and then a simple degradation pathway of THF was proposed. This work indicated that the Fenton process was an efficient and feasible pre-treatment method for THF wastewater.

scholarly journals Thermally activated persulfate treatment and mineralization of a recalcitrant high TDS petrochemical wastewater

2017 ◽  
Vol 19 (2) ◽  
pp. 72-77 ◽  
Author(s):  
Sahand Jorfi ◽  
Sudabeh Pourfadakari ◽  
Mehdi Ahmadi ◽  
Hamideh Akbari
Keyword(s):  
Ph Value ◽  
Cod Removal ◽  
Order Kinetic ◽  
Operational Parameters ◽  
Batch Mode ◽  
Thermally Activated ◽  
Toc Removal ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Activated Persulfate

Abstract Thermally activated persulfate efficiency for the treatment of a recalcitrant high TDS wastewater was investigated. The specific character of studied wastewater was high TDS content of around 23820 mg/L and BOD5/COD ratio of 0.07. Effective operational parameters including initial pH values of 3–9, reaction temperature of 40–80°C and persulfate concentrations of 0.5–5 g/L for COD removal were investigated in batch mode experiments. Removal efficiency was pH and temperature dependent. The COD and TOC removal of 94.3% and 82.8% were obtained at persulfate concentration of 4 g/L, initial pH value of 5 and temperature of 70°C after 180 min for initial COD concentration of 1410 mg/L. The pseudo first-order kinetic model was best fitted with COD removal (R2 = 0.94).

Pretreatment of Lead 2, 4, 6-trinitroresorcinol Wastewater by Fe-C Internal Electrolysis Process

2014 ◽  
Vol 955-959 ◽  
pp. 1955-1961 ◽  
Author(s):  
Li Heng Liu ◽  
Yan Lin ◽  
Qiang He
Keyword(s):  
Reaction Time ◽  
Orthogonal Experiment ◽  
Volume Ratio ◽  
Degradation Process ◽  
Reaction Rate Constant ◽  
Cod Removal ◽  
Process Conditions ◽  
Order Kinetic ◽  
Electrolysis Process ◽  
Internal Electrolysis

In this study, Fe/C internal electrolysis was used to pretreat the wastewater of lead 2, 4, 6-trinitroresorcinate (LTNR) production. The influences of pH, acids, reaction time and Fe/C volume ratio on COD removal were investigated. The optimum condition of iron-carbon electrolysis was determined by orthogonal experiment. And the reaction kinetics of COD removal and mechanism of contaminant removal were preliminary explored. The results showed that wastewater pH adjusted by sulfuric acid was more economical and better for COD removal. The effect of pH is the greatest. Two processes programs (pH3, Fe/C volume ratio 1.0, reaction time 24hr; pH3, Fe/C volume ratio 1.2, reaction time 18hr) are advised in project. Under the two process conditions, COD removal rates are 73.78% and 72.42%, respectively. The COD removal could be well described by pseudo-second-order kinetic model, and the reaction rate constant is 2.804×10-4 L/(mg·hr). Within the range of 0-24hr, film diffusion is the rate controlling step of the electrolysis process. The degradation process of trinitroresorcinate may be as follow: trinitroresorcinate→nitroaniline phenol or phenol aniline →nitrobenzene quinone or benzoquinone and ammonia→biodegradable or inorganics and nitrate.

scholarly journals Degradation of Norfloxacin in an Aqueous Solution by the Nanoscale Zero-Valent Iron-Activated Persulfate Process

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yanchang Zhang ◽  
Lin Zhao ◽  
Yongkui Yang ◽  
Peizhe Sun
Keyword(s):  
Degradation Process ◽  
High Reactivity ◽  
Degradation Efficiency ◽  
Zero Valent Iron ◽  
Order Kinetic ◽  
Paramagnetic Resonance ◽  
Promising Alternative ◽  
Quenching Effect ◽  
Nanoscale Zero Valent Iron ◽  
Initial Ph

In this study, nanoscale zero-valent iron (nZVI) was synthesized and used to activate persulfate (PS) for the degradation of norfloxacin (NOR). The nZVI/PS system exhibited a high reactivity towards NOR, and the degradation efficiency of NOR (100 mg/L) reached 93.8% with 0.1 g/L nZVI, 12 mM PS, and an initial pH of 7.0 within 7 min. The NOR degradation followed a pseudo-first-order kinetic model, and the effects of parameters such as nZVI dosage, PS concentration, initial pH, and temperature were investigated systematically. Overloading of nZVI lowered the degradation efficiency owing to the quenching effect of excessive Fe2+. The higher PS concentration and temperature favored the degradation of NOR. The influence of pH was not obvious, and the degradation was effective in a wide pH range. In addition, the radical quenching experiments and electron paramagnetic resonance (EPR) indicated that both sulfate radical (SO4⋅-) and hydroxyl radical (OH⋅) were the dominant radicals in the degradation process, in which the latter played a more important role. Finally, three degradation pathways were proposed based on the result of intermediates identified by liquid chromatography-mass spectrometry. Overall, this study indicated that the nZVI/PS system could provide a promising alternative for NOR wastewater treatment.

scholarly journals Pretreatment of Color Filter Wastewater towards Biodegradable by Fresnel-Lens-Assisted Solar TiO2Photocatalysis

2012 ◽  
Vol 2012 ◽  
pp. 1-8
Author(s):  
Wen-Shiuh Kuo ◽  
Min-Tian Li
Keyword(s):  
Reaction Time ◽  
Fresnel Lens ◽  
Solar Irradiation ◽  
Treated Wastewater ◽  
Color Filter ◽  
Photocatalytic Process ◽  
High Concentration ◽  
Toc Removal ◽  
Initial Ph ◽  
Critical Process Parameters

The pretreatment of color filter wastewater towards biodegradable by Fresnel-lens-enhanced solar TiO2photocatalytic process was investigated. The experimental design of response surface methodology (RSM) was employed to assess the effect of critical process parameters (including initial pH, TiO2dosage, and reaction time) on pretreatment performance in terms of BOD5/COD, COD and TOC removal efficiency. Appropriate reaction conditions were established as an initial pH of 7.5, a TiO2dosage of 1.5 g/L with a reaction time of 3 h for increasing the BOD5/COD ratio to 0.15, which implied that the treated wastewater would be possibly biodegradable. Meanwhile, the efficiency of COD and TOC removals reached 32.9% and 24.4%, respectively. With the enhancement of Fresnel lens, the required reaction time for improving the biodegradability of wastewater to 0.15 was 1 h only. Moreover, the efficiency of COD and TOC removals was promoted to 37.4% and 25.8%, respectively. This could be mainly due to the concentrated effect of Fresnel lens for solar energy, including an increase of 2 times of solar irradiation and a raising of 15–20°C of wastewater temperature. Consequently, solar TiO2photocatalytic process with the use of a PMMA Fresnel lens could offer an economical and practical alternative for the pretreatment of industry wastewater containing diversified biorefractory pollutants with a high concentration of COD such as color filter wastewater.

Pharmaceutically Active Compounds Degradation Using Doped TiO2 Functionalized Zeolite Photocatalyst

2018 ◽  
Vol 69 (1) ◽  
pp. 34-37 ◽  
Author(s):  
Monica Ihos ◽  
Corneliu Bogatu ◽  
Carmen Lazau ◽  
Florica Manea ◽  
Rodica Pode
Keyword(s):  
Organic Carbon ◽  
Active Compound ◽  
Uv Spectra ◽  
Pharmaceutically Active Compounds ◽  
Mineralization Process ◽  
Active Compounds ◽  
Spectra Analysis ◽  
Doped Tio2 ◽  
Toc Removal ◽  
Pharmaceutically Active Compound

The aim of this study was the investigation of photocatalytic degradation of pharmaceutically active compounds using doped TiO2 functionalized zeolite photocatalyst. Diclofenac (DCF), a non-steroidal anti-inflammatory drug, that represents a biorefractory micropollutant, was chosen as model of pharmaceutically active compound. The photocatalyst was Z-TiO2-Ag. The concentration of DCF in the working solutions was 10 mg/L,50 mg/L,100 mg/L and 200 mg/L and of photocatalyst 1 g/L in any experiments. The process was monitored by recording the UV spectra of the treated solutions and total organic carbon (TOC) determination. The UV spectra analysis and TOC removal proved that along the advanced degradation of DCF also a mineralization process occurred. The carried out research provided useful information envisaging the treatment of pharmaceutical effluents by photocatalysis.

Chitosan-based Magnetic Composites - Efficient Adsorbents for Removal of Pb(II) and Cu(II) from Aqueous Mono and Bicomponent Solutions

2018 ◽  
Vol 69 (9) ◽  
pp. 2323-2330 ◽  
Author(s):  
Daniela C. Culita ◽  
Claudia Maria Simonescu ◽  
Rodica Elena Patescu ◽  
Nicolae Stanica
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Chemical Properties ◽  
Order Kinetic ◽  
Mass Ratio ◽  
Magnetic Adsorbent ◽  
Magnetic Composites ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Physical And Chemical

A series of three chitosan-based magnetic composites was prepared through a simple coprecipitation method. It was investigated the influence of mass ratio between chitosan and magnetite on the physical and chemical properties of the composites in order to establish the optimum conditions for obtaining a composite with good adsorption capacity for Pb(II) and Cu(II) from mono and bicomponent aqueous solutions. It was found that the microspheres prepared using mass ratio chitosan / magnetite 1.25/1, having a saturation magnetization of 15 emu g--1, are the best to be used as adsorbent for the metal ions. The influence of different parameters such as initial pH values, contact time, initial concentration of metal ions, on the adsorption of Pb(II) and Cu(II) onto the chitosan-based magnetic adsorbent was investigated in details. The adsorption process fits the pseudo-second-order kinetic model in both mono and bicomponent systems, and the maximum adsorption capacities calculated on the basis of the Langmuir model were 79.4 mg g--1 for Pb(II) and 48.5 mg g--1 for Cu(II) in monocomponent systems, while in bicomponent systems were 88.3 and 49.5 mg g--1, respectively. The results revealed that the as prepared chitosan-based magnetic adsorbent can be an effective and promising adsorbent for Pb(II) and Cu(II) from mono and bicomponent aqueous solutions.

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