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.

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%.

A comparative treatment of bleaching wastewater by physicochemical processes

2017 ◽  
Vol 76 (9) ◽  
pp. 2367-2379 ◽  
Author(s):  
Ninad Oke ◽  
Swati Singh ◽  
Anurag Garg
Keyword(s):  
Mixing Time ◽  
Oxygen Demand ◽  
Chloride Ion ◽  
Paper Mill ◽  
Ion Concentration ◽  
Treated Wastewater ◽  
Molar Ratio ◽  
Chlorinated Organic Compounds ◽  
H2o2 Treatment ◽  
Toc Removal

Abstract The bleaching effluent discharged from a pulp and paper mill contains chlorinated organic compounds which are toxic to living matter. Physicochemical treatments such as coagulation and different advanced oxidation processes (AOPs) were employed for combined bleaching effluent generated from the first two stages (i.e. chlorination and alkali extraction) (pH = 3.5, chemical oxygen demand (COD) = 1,920 mg/L, and total organic carbon (TOC) = 663 mg/L). At optimum conditions (pH = 7.5, polyaluminium chloride (PAC) dose = 3.84 g/L and slow mixing time = 25 min), ∼68% removal in UV254 and ∼23% TOC removal was obtained during coagulation. Among various AOPs, UV/Fe2+/TiO2/H2O2 system showed the highest TOC and COD removals (∼78%) after 2 h duration (Fe2+:H2O2 molar ratio = 1:100). After the AOP process, chloride ion concentration and biodegradability of the treated wastewater was increased to 2,762 mg/L and 0.46 from an initial value of 2,131 mg/L and 0.29, respectively. The wastewater and sludge analysis showed oxidation and adsorption as the major mechanisms for organics removal. Upon reuse of the regenerated catalysts, TOC removal was reduced significantly. It was found that three times more sludge per unit TOC removal was generated after coagulation in comparison to that produced after UV/Fe2+/TiO2/H2O2 treatment.

scholarly journals The research on the control of chlorinated by-products by the combined process of three-dimensional electrode system and ultraviolet-photocatalytic oxidation

2021 ◽  
Author(s):  
Li Wang ◽  
Hong Liang ◽  
Kaibin Zhang ◽  
Hong Huang ◽  
Qingchun Wang
Keyword(s):  
Photocatalytic Oxidation ◽  
Degradation Mechanism ◽  
Three Dimensional ◽  
Oxygen Demand ◽  
Advanced Oxidation ◽  
Chloride Ion ◽  
Ion Concentration ◽  
Dominant Factor ◽  
Treatment Technology ◽  
By Products

Abstract Advanced oxidation technology is considered to be the most potential wastewater treatment technology. As one of the advanced oxidation technologies, three-dimensional electrochemical system (3DES) is often used to treat industrial wastewater that is difficult to degrade. Sulphonated phenolic resin (SMP) was treated as a characteristic pollutant in sulfonated drilling wastewater. The separate effect of current, the dosage of particle electrodes, chloride ion concentration and initial pH on chlorinated by-products were analyzed by the response surface methodology (RSM). Results showed that the current is the most dominant factor, followed by the dosage of particle electrodes. The ultraviolet-electrolysis (UVEL) system was implemented by adding ultraviolet light under the optimal electrolysis (EL) system. The chemical oxygen demand (CODcr) and total organic carbon (TOC) removal rates of the UVEL system were respectively increased by 19% and 29.39% compared with the EL system, the concentration of chlorinated by-products was also reduced by 534.4 mg/L when the UV irradiance was 5.24 mW/cm2. These results indicated that the UVEL system degrades SMP more thoroughly. The enhanced reaction mechanism of UVEL system and the possible degradation pathway for SMP were proposed via controlling free radical quenching experiments and the product of EL and UVEL processes. The results showed that the high degradation efficiency of the UVEL system can be attributed to the synergistic degradation mechanism present in the UVEL system, where the photolysis of active chlorine species (ACl) promotes the increase of hydroxyl radical (·OH).

scholarly journals Biotreatment of industrial tannery wastewater using Botryosphaeria rhodina

2011 ◽  
Vol 76 (3) ◽  
pp. 439-446 ◽  
Author(s):  
Claudia Hasegawa ◽  
Aneli Barbosa ◽  
Keiko Takashima
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Organic Compounds ◽  
Oxygen Demand ◽  
Chloride Ion ◽  
Ion Concentration ◽  
Tannery Wastewater ◽  
Botryosphaeria Rhodina ◽  
Wastewater Samples ◽  
Almost All

The treatment of a tannery wastewater was performed on the laboratory scale using the ascomyceteous fungus Botryosphaeria rhodina MAMB-05, a ligninolytic and a constitutive producer of laccases (EC: 1.10.3.2). The wastewater samples were collected in the retanning and dyeing steps and presented high values of chemical oxygen demand, COD, (15,023 ? 60.0 mg L-1), fifth-day biochemical oxygen demand, BOD5, (4,374 ? 0.1 mg L-1), total solids (28,500 ? 2.0 mg L-1), total organic carbon, TOC, (4,685 mg L-1), and chloride ion concentration (2,911 ? 0.3 mg L-1). The fungus was inoculated and after five days under agitation at 180 rpm at 28?C, the COD was reduced by 91%. The total organic carbon also decreased from 4,685 to 375.0 mg L-1 and the turbidity from 331.0 to 6.5 NTU, indicating that the biological treatment was efficient as the fungus consumed almost all the organic compounds present in the wastewater. It was not necessary to add an additional carbon source for the treatment, indicating that the concentration of organic compounds presented in the tannery wastewater effluent were sufficient for microorganism growth, during which the COD and TOC were reduced by about 91 and 93%, respectively.

scholarly journals Similarities among small watercourses based on multiparameter physico-chemical measurements

2020 ◽  
Author(s):  
Máté Krisztián Kardos ◽  
Adrienne Clement
Keyword(s):  
Human Impact ◽  
Inorganic Nitrogen ◽  
Oxygen Demand ◽  
Chloride Ion ◽  
Water Quality Monitoring ◽  
Point Sources ◽  
Water Bodies ◽  
Ion Concentration ◽  
Linear Discriminant ◽  
Physico Chemical

Abstract With the introduction of the Water Framework Directive, the relative importance of smaller waterways increased. This statement is particularly true for Hungary, where water-quality monitoring of most smaller rivers only began 12 years ago. Due to their large number, and the lack of historical data concerning their state, systematic monitoring is a challenge. In the current study, 101 creeks are characterized on the one hand by 13 physico-chemical quality parameters (pH, electric conductivity, chloride ion concentration, dissolved oxygen, oxygen saturation, biochemical oxygen demand, chemical oxygen demand, total organic carbon, ammonium nitrogen, total inorganic nitrogen, total nitrogen, orthophosphate and total phosphorus), on the other hand by their watershed's relief, land use, and point sources' pollution indicators. Euclidean distance between water bodies (henceforth WBs) is calculated according to normalized physico-chemical monitoring values. They are grouped into clusters using the hierarchical clustering method. Watershed characteristics are used to explain the clustering via linear discriminant analysis. The investigation revealed that the main driver of cluster group creation is related to human impact: diffuse agricultural and point-source pollution. The first of the three clusters involved water bodies with low or no human impact; the second cluster contained those with medium-level anthropogenic disturbance, while waters with high pollution values formed the third cluster. Mean distance between heavily polluted waters was 1.5 times higher than that between those showing no or low disturbance, meaning that pristine waters are more similar to one another than polluted ones. The current number of samples per river is twice as high in cluster 1 as in cluster 3, revealing that there is room for optimization of the monitoring system. This contribution uses Hungary as a case study.

scholarly journals Anaerobic–aerobic sequencing batch reactor treating azo dye containing wastewater: effect of high nitrate ions and salt

2017 ◽  
Vol 8 (2) ◽  
pp. 251-261 ◽  
Author(s):  
Ali Assadi ◽  
Morteza Naderi ◽  
Mohammad Reza Mehrasbi
Keyword(s):  
Retention Time ◽  
Azo Dye ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Salt Content ◽  
Oxygen Demand ◽  
Ion Concentration ◽  
Solid Retention Time ◽  
Nitrate Ion ◽  
Operational Conditions

Abstract In this work, the treatment of wastewater containing azo dye using anaerobic–aerobic sequencing batch reactor (SBR) based on mixed culture for its efficacy in decolorization and reduction in chemical oxygen demand (COD) under different operational conditions has been analyzed. Effects of hydraulic retention time (HRT), salts content and nitrate ion concentration on the rate and extent of color and COD removal through 180 days containing steady-state and acclimation periods were investigated. Solid retention time was kept constant at 20 days in all experiments. Almost complete decolorization could be achieved at dye concentrations between 5 and 500 mg/L, but the removal of COD decreased gradually from 90 to 65% with increasing dye concentration. The results indicated that color was mainly removed under anaerobic conditions and it was almost filled out within 2–3 h of the anaerobic residence time with up to 98% decolorization efficiency. Besides, cutting the cycle time from 24 to 8 h does not have an effect on color removal. Increases in HRT provide enough time for partial mineralization of COD and intermediates in SBR system. The rates of color and COD removals decreased with increasing salt content and nitrate ion concentration in the feed wastewater.

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).

Hydro-geochemical properties with respect to landuse in the southernmost river of Kerala

2018 ◽  
Vol 6 (1) ◽  
Author(s):  
Badusha M. ◽  
Santhosh S
Keyword(s):  
Organic Carbon ◽  
Drainage Basin ◽  
Anthropogenic Activities ◽  
Oxygen Demand ◽  
Ion Concentration ◽  
Total Hardness ◽  
Hydrogen Ion Concentration ◽  
Geochemical Properties ◽  
Quality Of Water

The hydro geochemical features of Neyyar River for a period of one year from May 2015 to April 2016 were analyzed. Six sampling sites were fixed considering physiography and present landuse pattern of the river basin. The residents in the drainage basin are primarily responsible for framing a better landuse and thereby maintain a good water and sediment regime. Geospatial pattern of the present landuse of the study area indicated that the sustainability of this river ecosystem is in danger due to unscientific landuse practices, which is reflected in the river quality as well. The parameters such as hydrogen ion concentration, electrical conductivity, chloride, Biological Oxygen Demand, total hardness and sulphate of river water and Organic Carbon of river bed sediments were analyzed in this study. The overall analysis shows that the highland areas are characterized by better quality of water together with low organic carbon, which is mainly due to better landuse and minimal reclamation. The midland and lowland areas are characterized by poor quality of water with high organic carbon, which is due to high anthropogenic activities and maximum pollutants associated with the region together with the alteration in landuse from a traditional eco-friendly pattern to a severely polluted current pattern.

scholarly journals First Attempts of the Use of 195Pt NMR of Phenylbenzothiazole Complexes as Spectroscopic Technique for the Cancer Diagnosis

Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3970 ◽  
Author(s):  
Bruna T. L. Pereira ◽  
Mateus A. Gonçalves ◽  
Daiana T. Mancini ◽  
Kamil Kuca ◽  
Teodorico C. Ramalho
Keyword(s):  
Cancer Treatment ◽  
Cancer Diagnosis ◽  
Density Functional ◽  
Chemical Shifts ◽  
Chloride Ion ◽  
Platinum Complexes ◽  
Dft Method ◽  
Ion Concentration ◽  
Implicit Solvent ◽  
Early Cancer Diagnosis

Platinum complexes have been studied for cancer treatment for several decades. Furthermore, another important platinum characteristic is related to its chemical shifts, in which some studies have shown that the 195Pt chemical shifts are very sensitive to the environment, coordination sphere, and oxidation state. Based on this relevant feature, Pt complexes can be proposed as potential probes for NMR spectroscopy, as the chemical shifts values will be different in different tissues (healthy and damaged) Therefore, in this paper, the main goal was to investigate the behavior of Pt chemical shifts in the different environments. Calculations were carried out in vacuum, implicit solvent, and inside the active site of P13K enzyme, which is related with breast cancer, using the density functional theory (DFT) method. Moreover, the investigation of platinum complexes with a selective moiety can contribute to early cancer diagnosis. Accordingly, the Pt complexes selected for this study presented a selective moiety, the 2-(4′aminophenyl)benzothiazole derivative. More specifically, two Pt complexes were used herein: One containing chlorine ligands and one containing water in place of chlorine. Some studies have shown that platinum complexes coordinated to chlorine atoms may suffer hydrolyses inside the cell due to the low chloride ion concentration. Thus, the same calculations were performed for both complexes. The results showed that both complexes presented different chemical shift values in the different proposed environments. Therefore, this paper shows that platinum complexes can be a potential probe in biological systems, and they should be studied not only for cancer treatment, but also for diagnosis.

scholarly journals Broadband dielectric spectroscopy for monitoring temperature-dependent chloride ion motion in BiOCl plates

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Adrian Radoń ◽  
Dariusz Łukowiec ◽  
Patryk Włodarczyk
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Spectroscopy ◽  
Low Frequency ◽  
Chloride Ion ◽  
Ion Source ◽  
Chloride Ions ◽  
Ion Concentration ◽  
Broadband Dielectric Spectroscopy ◽  
Free Chloride ◽  
Structure Rebuilding

AbstractThe dielectric properties and electrical conduction mechanism of bismuth oxychloride (BiOCl) plates synthesized using chloramine-T as the chloride ion source were investigated. Thermally-activated structure rebuilding was monitored using broadband dielectric spectroscopy, which showed that the onset temperature of this process was 283 K. This rebuilding was related to the introduction of free chloride ions into [Bi2O2]2+ layers and their growth, which increased the intensity of the (101) diffraction peak. The electrical conductivity and dielectric permittivity were related to the movement of chloride ions between plates (in the low-frequency region), the interplanar motion of Cl− ions at higher frequencies, vibrations of these ions, and charge carrier hopping at frequencies above 10 kHz. The influence of the free chloride ion concentration on the electrical conductivity was also described. Structure rebuilding was associated with a lower concentration of free chloride ions, which significantly decreased the conductivity. According to the analysis, the BiOCl plate conductivity was related to the movement of Cl− ions, not electrons.

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