Removal of clomazone herbicide from a synthetic effluent by electrocoagulation

2016 ◽  
Vol 73 (12) ◽  
pp. 2944-2952 ◽  
Author(s):  
Cristina Benincá ◽  
Fernanda T. Vargas ◽  
Manoel L. Martins ◽  
Fábio F. Gonçalves ◽  
Rodrigo P. Vargas ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Tap Water ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Gas Chromatography Mass Spectrometry ◽  
Dioic Acid ◽  
Apparent Color ◽  
Initial Ph ◽  
In Series ◽  
Synthetic Solution

Abstract The aim of this work was to investigate the kinetics of removal of clomazone herbicide from an aqueous solution by electrocoagulation. The experiments were performed in a cylindrical batch reactor with six aluminum electrodes in monopolar mode, arranged in series and connected to a digital DC power. The aqueous solution (tap water + clomazone) with initial pH close to 7.9 was always treated at ambient temperature (≈20 °C) and atmospheric pressure for 5,400 s. For a confidence level of 95% the rate constant of electrocoagulation and the efficiency of removal of clomazone at equilibrium were 2.1 × 10−3 ± 0.5 × 10−3 s−1 and 97.7 ± 2.2%, respectively. The final chemical oxygen demand was 88% lower than that measured initially, while turbidity and apparent color were totally removed from the synthetic solution at a rate close to that of formation of aluminum hydroxides. Some reaction intermediates, such as benzonitrile-2-chloro and 2-chloro-hex-2,4-diene-1,6-dioic-acid determined by gas chromatography mass spectrometry (GC-MS) analysis, explain the ratio of equilibrium to initial total organic carbon approximately between 0.6 and 0.8 at a probability of 95%.

scholarly journals TiO2 BEADS FOR PHOTOCATALYTIC DEGRADATION OF HUMIC ACID IN PEAT WATER

2011 ◽  
Vol 11 (3) ◽  
pp. 253-257 ◽  
Author(s):  
Winarti Andayani ◽  
Agustin N M Bagyo
Keyword(s):  
Aqueous Solution ◽  
Humic Acid ◽  
Oxalic Acid ◽  
Chemical Oxygen Demand ◽  
Photocatalytic Degradation ◽  
Uv Light ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Color Intensity ◽  
Before And After

Degradation of humic acid in aqueous solution containing TiO2 coated on ceramics beads under irradiation of 254 nm UV light has been conducted in batch reactor. The aim of this experiment was to study photocatalytic degradation of humic acid in peat water. The irradiation of the humic acid in aqueous solution was conducted in various conditions i.e solely uv, in the presence of TiO2-slurry and TiO2 beads. The color intensity, humic acid residue, conductivity and COD (chemical oxygen demand) of the solution were analyzed before and after irradiation.  The compounds produced during photodegradation were identified using HPLC. The results showed that after photocatalytic degradation, the color intensity and the COD value of the solution decreased, while the conductivity of water increased indicating mineralization of the peat water occurred. In addition, oxalic acid as the product of degradation was observed.

Adsorption of Nitrobenzene and Benzoic Acid from Aqueous Solution by All-Silica Zeolite Beta

2011 ◽  
Vol 183-185 ◽  
pp. 1378-1382 ◽  
Author(s):  
Qing Dong Qin ◽  
Jun Ma ◽  
Da Fang Fu
Keyword(s):  
Aqueous Solution ◽  
Benzoic Acid ◽  
Contact Time ◽  
Batch Reactor ◽  
Zeolite Beta ◽  
Reactor System ◽  
Equilibrium Isotherm ◽  
Initial Concentration ◽  
Initial Ph ◽  
Increasing Temperature

All-silica zeolite beta (BEA) was tested for the ability to remove nitrobenzene and benzoic acid from aqueous solution. The effect of contact time, temperature, initial concentration and initial pH were investigated in a batch reactor system. Adsorption of nitrobenzene decreased with increase in temperature. The equilibrium isotherm was L-shaped. Nitrobenzene adsorption was independent of pH. Adsorption of benzoic acid increased with increasing temperature from 5 °C to 22 °C and decreased with increasing temperature from 22°C to 32 °C. The equilibrium isotherm was approximately S-shaped. Benzoic acid adsorption was dependent of pH. At pH8.0, benzoic acid can also be adsorbed effectively. The results above confirmed that BEA had the potential to be utilized as relatively effective adsorbent for nitrobenzene and benzoic acid removal.

scholarly journals Treatment of a Mature Landfill Leachate: Comparison between Homogeneous and Heterogeneous Photo-Fenton with Different Pretreatments

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1849 ◽  
Author(s):  
Javier Tejera ◽  
Ruben Miranda ◽  
Daphne Hermosilla ◽  
Iñigo Urra ◽  
Carlos Negro ◽  
...  
Keyword(s):  
Ferric Chloride ◽  
Landfill Leachate ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Economic Assessment ◽  
Total Treatment Cost ◽  
Similar Chemical ◽  
Total Treatment ◽  
Initial Ph ◽  
Mature Landfill Leachate

This study focuses on the treatment of a mature landfill leachate by coagulation and photo-Fenton at different conditions. Optimal coagulation is carried out with ferric chloride in acid conditions; and with alum in near-neutral conditions, to minimize the use of sulphuric acid for pH adjustment (1 g/L vs. 7.2 g/L), the generation of sludge and the increase of conductivity in the final effluent. In both cases, a similar chemical oxygen demand (COD) removal is obtained, higher than 65%, which is high enough for a subsequent photo-Fenton treatment. However, the removal of absorbance at 254 nm (UV-254) was significantly higher with ferric chloride (83% vs. 55%), due to the important removal of humic acids at acid pH. The best results for coagulation are 2 g/L ferric chloride at initial pH = 5 and 5 g/L alum at initial pH = 7. After coagulation with ferric chloride, the final pH (2.8) is adequate for a homogeneous photo-Fenton using the remaining dissolved iron (250 mg/L). At these conditions, using a ratio H2O2/COD = 2.125 and 30 min contact time, the biodegradability increased from 0.03 to 0.51. On the other hand, the neutral pH after alum coagulation (6.7) allows the use of zero valent iron (ZVI) heterogeneous photo-Fenton. In this case, a final biodegradability of 0.32 was obtained, after 150 min, using the same H2O2/COD ratio. Both treatments achieved similar results, with a final COD, UV-254 and color removal greater than 90%. However, the economic assessment shows that the approach of ferric chloride + homogeneous photo-Fenton is much cheaper (6.4 €/m3 vs. 28.4 €/m3). Although the discharge limits are not achieved with the proposed combination of treatments, the significant increase of the pre-treated leachate biodegradability allows achieving the discharge limits after a conventional biological treatment such as sequencing batch reactor, which would slightly increase the total treatment cost.

Electrochemical treatment and operating cost analysis of textile wastewater using sacrificial iron electrodes

2009 ◽  
Vol 60 (9) ◽  
pp. 2261-2270 ◽  
Author(s):  
M. Kobya ◽  
E. Demirbas ◽  
A. Akyol
Keyword(s):  
Current Density ◽  
Batch Reactor ◽  
Operating Cost ◽  
Oxygen Demand ◽  
Textile Wastewater ◽  
Iron Electrode ◽  
Treated Wastewater ◽  
Experimental Conditions ◽  
Potential Measurement ◽  
Initial Ph

Electrocoagulation (EC) method with iron electrode was used to treat the textile wastewater in a batch reactor. Iron electrode material was used as a sacrificial electrode in monopolar parallel mode in this study. The removal efficiencies of the wastewater by EC were affected by initial pH of the solution, current density, conductivity and time of electrolysis. Under the optimal experimental conditions (initial pH 6.9, current density of 10 mA/cm2, conductivity of 3,990 μS/cm, and electrolysis time of 10 min), the treatment of textile wastewater by the EC process led to a removal capacity of 78% of chemical oxygen demand (COD) and 92% of turbidity. The energy and electrode consumptions at the optimum conditions were calculated to be 0.7 kWh/kg COD (1.7 kWh/m3) and 0.2 kgFe/kg COD (0.5 kgFe/m3), respectively. Moreover, the operating cost was calculated as 0.2 €/kg removed COD or 0.5 €/m3 treated wastewater. Zeta potential measurement was used to determine the charge of particle formed during the EC which revealed that Fe(OH)3 might be responsible for the EC process.

Photochemical degradation of 4-chlorophenol in the aqueous phase using peroxyacetic acid (PAA)

2013 ◽  
Vol 67 (2) ◽  
pp. 440-445 ◽  
Author(s):  
Mausumi Mukhopadhyay ◽  
Dhiraj P. Daswat
Keyword(s):  
Batch Reactor ◽  
Oxygen Demand ◽  
Chloride Ion ◽  
Degradation Process ◽  
Ion Concentration ◽  
Gas Chromatography Mass Spectrometry ◽  
Uv Spectrophotometry ◽  
Photochemical Degradation ◽  
Peroxyacetic Acid ◽  
Residual Concentration

The photochemical degradation of 4-chlorophenol (4-CP) using ultraviolet irradiation (UV) of 6, 12 and 18 W with peroxyacetic acid (PAA) was studied in a batch reactor. The objective of this work was to investigate degradation and mineralization of 4-CP by PAA. The degradation efficiency increased with increasing UV input. The degradation process was also pH and initial PAA concentration dependent. The optimum conditions for the photochemical degradation of 4-CP as UV input, pH and PAA concentration was found to be 18 W, 9.5 and 3,040 ppm. The reaction efficiency decreased with increasing initial 4-CP concentrations. More than 95% mineralization of 4-CP was achieved with the UV/PAA process. The chloride ion concentration and chemical oxygen demand (COD) was evaluated. The chloride ion concentration and COD were decreased gradually with increasing UV input. Samples were analyzed by high pressure liquid chromatography (HPLC), UV spectrophotometry and gas chromatography–mass spectrometry (GC-MS) for residual concentration and identification of final degraded products.

scholarly journals Treatment of Wastewaters Olive Mill by Electrocoagulation and Biological Process

2017 ◽  
pp. 295-304
Author(s):  
M. Neffa ◽  
H. Hanine ◽  
B. Lekhlif ◽  
M. Taourirt ◽  
K. Habbari
Keyword(s):  
Chemical Oxygen Demand ◽  
Tap Water ◽  
Oxygen Demand ◽  
Olive Mill Wastewater ◽  
Small Scale ◽  
Olive Mill Wastewaters ◽  
Initial Ph ◽  
Environmental Pollution Problem ◽  
High Chemical Oxygen Demand ◽  
Olive Mill

Olive mill wastewaters (OMWW) cause a recurrent environmental pollution problem. Treatment and reuse of olive mill wastewater (OMWW) presents significant challenges both due to the nature of olive oil production (seasonal and small scale) and due to the characteristics of the wastewater (high chemical oxygen demand (COD) and high phenolic content in the organic fraction of OMWW principally responsible for the phytotoxicity and microbial growth inhibitory effects of the effluent). In the present work the combined pretreatment of actual olive mill wastewaters by electrocoagulation and coagulation with natural organic coagulant, such as TNN and Kim 2212, and the biological purification, was investigated. Tests were conducted with raw OMWW and diluted with tap water at pH neuter adjusted by adding lime coagulant with chemical oxygen demand (COD) contents of 178 g d'O2.l-1, total suspended solids (TSS) of 6,4 g/L, Conductivity (mS.cm-1) of 29, pH of 4,8 and turbidity of 50 NTK. The optimum removal of COD, turbidity and total polyphenolic was respectively 38,39 % , 74,45 % and 60%. This results was obtained with TNN coagulation at pH (7) and 20 mg/l of the coagulant . The maximum organic matter removals by electrocoagulation (56.76%) processes was achieved after 90 min, by using 15V/m² voltage kept constant for each run at initial pH of the OMWW (4,4). Olive mill wastewater (OMWW) was then treated aerobically with fungi. The results show that the fungus is capable of reducing chemical oxygen demand 68% and 75% for the diluted OMWW at 50 % treated by lime and lime/KIM 2120 respectively, after only 5 days of growth. Neutral pH seems supported aerobic treatment.

Integration of US/Fe2+ and photo-Fenton in sequencing for degradation of landfill leachate

2015 ◽  
Vol 73 (2) ◽  
pp. 260-266 ◽  
Author(s):  
F. G. Zha ◽  
D. X. Yao ◽  
Y. B. Hu ◽  
L. M. Gao ◽  
X. M. Wang
Keyword(s):  
Removal Efficiency ◽  
Landfill Leachate ◽  
Oxygen Demand ◽  
Gas Chromatography Mass Spectrometry ◽  
Fenton Process ◽  
Optimal Conditions ◽  
Initial Concentration ◽  
Toc Removal ◽  
The Us ◽  
Initial Ph

The landfill leachate treated by sonication in presence of Fe2+ (US/Fe2+) and then by photo-Fenton achieved the highest total organic carbon (TOC) removal efficiency among the screened processes. The lower initial pH, dosage of Fe2+ and initial concentration of leachate were helpful in raising TOC removal efficiency of leachate by US/Fe2+. The optimal conditions for the US-photo-Fenton process were as follows: initial pH at 3.0, [H2O2]/[TOC0] at 2, [H2O2]/[Fe2+] at 5 and initial concentration of landfill leachate at 600 mg/L. The removal efficiency of TOC, chemical oxygen demand (COD) and 5-day biochemical oxygen demand (BOD5) were 68.3, 79.6 and 58.2%, while the BOD5/COD rose from 0.20 to 0.43 at optimum condition. Based on gas chromatography–mass spectrometry (GC-MS) results, 36 of a total of 56 pollutants were completely degraded by US-photo-Fenton treatment.

scholarly journals RESPONSE SURFACE METHODOLOGY AND DESIRABILITY FUNCTION AS STATISTICAL TOOLS IN THE OPTIMIZATION OF ELECTROCOAGULATION PROCESS IN SURFACE WATER

2020 ◽  
Vol 6 (2) ◽  
pp. 0152-0163
Author(s):  
Efraim Lázaro Reis ◽  
Maria Paulina Mendonza Combatt ◽  
Karina Esther Vasquez Sanjuan ◽  
Antônio Augusto Neves ◽  
Regina Célia Santos Mendonça
Keyword(s):  
Response Surface Methodology ◽  
Surface Water ◽  
Response Surface ◽  
Desirability Function ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Safe Work ◽  
Apparent Color ◽  
Initial Ph ◽  
Electrocoagulation Process

The electrocoagulation for water clarification for purification have been studied as alternative to the processes of the water treatment. This study aimed to model and to optimize this process for types of water with different turbidity conditions; considering the current intensity, electrolysis time and initial pH on apparent color removal, chemical oxygen demand and surface water turbidity. Electrocoagulation tests were make aluminum electrodes. The optimal operating conditions and models based on the response surface methodology were obtained with central composite design. In order to comply with the esthetic / organoleptic standard stipulated for this stage of the process, the characterization of the three types of water studied must have color < 15 uH, COD < 18 mg L-1 O2 and turbidity < 5 NTU). The correlation between the analyzed answers allows finding specific conditions of the parameters, assisting in the determination of safe work points in the operation of clarification.

Peranan BOD biosensor untuk proses optimasi pengolahan limbah sintetik di SBR

2019 ◽  
Vol 1 (2) ◽  
pp. 1
Author(s):  
Lindawati Lindawati
Keyword(s):  
Biochemical Oxygen Demand ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Oxygen Demand

Sebuah Sequencing Batch Reactor (SBR) digunakan untuk mengevaluasi peranan Biochemical Oxygen Demand (BOD) biosensor dalam proses optimasi proses pengolahan nutrien karbon, nitrogen dan fosfat. Hasil penelitian menunjukkan bahwa BOD biosensor dapat dipergunakan untuk penentuan karbon organik, sehingga reduksi siklus SBR dapat dilakukan dan efisiensi proses meningkat. Pola konsumsi karbon organik ditemukan dengan adanya ‘tanda diam’ pada fase anoksik/ anaerobik, di mana dari tanda ini, fase aerobik dapat segera dimulai. Reduksi durasi siklus SBR dari 8 jam menjadi 4 jam meningkatkan efiesiensi pengolahan C, N dan P yang meningkat pula (hampir dua kali lebih tinggi).

Use of Nanopillars-TiO2 Thin Films in the Photocatalytic Degradation of Bromophenol Blue from Aqueous Solution

2018 ◽  
Vol 6 (1) ◽  
pp. 22-30
Author(s):  
C. Lalhriatpuia ◽  
◽  
Thanhming liana ◽  
K. Vanlaldinpuia
Keyword(s):  
Thin Films ◽  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Batch Reactor ◽  
Bromophenol Blue ◽  
Tio2 Thin Films ◽  
Initial Concentration ◽  
Bet Specific Surface Area ◽  
Interfering Ions

The photocatalytic activity of Nanopillars-TiO2 thin films was assessed in the degradation of Bromophenol blue (BPB) dye from aqueous solution under batch reactor operations. The thin films were characterized by the XRD, SEM and AFM analytical methods. BET specific surface area and pore sizes were also obtained. The XRD data showed anatase phase of TiO2 particles with average particle size of 25.4 and 21.9 nm, for S1 and S2 catalysts respectively. The SEM and AFM images indicated the catalyst composed with Nanosized pillars of TiO2, evenly distributed on the surface of the substrate. The average height of the pillars was found to be 180 and 40 nm respectively for the S1 and S2 catalyst. The BET specific surface area and pore sizes of S1 and S2 catalyst were found to be 5.217 and 1.420 m2/g and 7.77 and 4.16 nm respectively. The photocatalytic degradation of BPB using the UV light was studied at wide range of physico-chemical parametric studies to determine the mechanism of degradation as well as the practical applicability of the technique. The batch reactor operations were conducted at varied pH (pH 4.0 to 10.0), BPB initial concentration (1.0 to 20.0 mg/L) and presence of several interfering ions, i.e., cadmium nitrate, copper sulfate, zinc chloride, sodium chloride, sodium nitrate, sodium nitrite, glycine, oxalic acid and EDTA in the photocatalytic degradation of BPB. The maximum percent removal of BPB was observed at pH 6.0 and a low initial concentration of the pollutant highly favours the photocatalytic degradation using thin films. The presence of several interfering ions suppressed the photocatalytic activity of thin films to some extent. The time dependence photocatalytic degradation of BPB was demonstrated with the pseudo-first-order rate kinetics. Study was further extended with total organic carbon measurement using the TOC (Total Organic Carbon) analysis. This demonstrated an apparent mineralization of BPB from aqueous solutions.

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