Electrochemical precipitation of chromium (Cr6+) from an electroplating wastewater

1995 ◽  
Vol 31 (9) ◽  
pp. 109-117 ◽  
Author(s):  
N. Kongsricharoern ◽  
C. Polprasert
Keyword(s):  
Electrical Potential ◽  
Fluorescence Analysis ◽  
Electrolytic Cell ◽  
Steel Plates ◽  
Volume Index ◽  
Electroplating Wastewater ◽  
Treatment Processes ◽  
Dc Power ◽  
Initial Ph ◽  
Cr Removal

This research was conducted in the laboratory to investigate an alternative of Cr removal from an electroplating wastewater using the electrochemical precipitation (ECP) process. The ECP unit consisted of an electrolytic cell made of two steel plates representing anode and cathode. The DC power source applied to the ECP unit had current (I) and electrical potential (E) of 3-6 A and 30-75 V, respectively. Electroplating wastewater used in the experiments contained Cr6+ in the range of 215-3860 mg/l, and the pH was 1.5. The parameters varied during the ECP experiments were: E, hydraulic retention time (HRT), Cr6+ concentration, conductivity and initial pH. The optimum ECP conditions found were electrical potential, 75 V; current, 4.8 A; HRT, 50 min; initial pH, above 3.2. Under these conditions, the Cr6+ concentrations remaining in the effluent were less than 0.2 mg/l. Sludge produced in the ECP unit had a sludge volume index (SVI) of 60-80, an indication of sludge settleability. X-ray fluorescence analysis of the ECP sludge revealed formation of Fe2O3 and FeCr2O4 as the main products. Power consumption of the ECP unit was found to be in the range of 14.7 - 20 kWh/m3 of wastewater. The economics of the ECP process was evaluated and compared with some conventional treatment processes for Cr removal.

Chromium removal by a bipolar electro-chemical precipitation process

1996 ◽  
Vol 34 (9) ◽  
pp. 109-116 ◽  
Author(s):  
N. Kongsricharoern ◽  
C. Polprasert
Keyword(s):  
Chemical Precipitation ◽  
Steel Plates ◽  
Precipitation Process ◽  
Steel Electrode ◽  
Electroplating Wastewater ◽  
X Ray ◽  
Treated Effluent ◽  
Bipolar Mode ◽  
Balance Analysis ◽  
Cr Removal

This research was conducted in laboratory to investigate an alternative for Cr removal from an electroplating wastewater using the electro-chemical precipitation (ECP) process. The ECP unit, operated in the bipolar mode, had six steel plates including the anode and cathode and was supplied with DC power. The electroplating wastewater used in the experiments contained Cr concentrations in the range of 570-2100 mg/l. The Cr removal efficiencies in the bipolar ECP units were higher than 99% and the Cr concentrations in the treated effluent were less than 0.5 mg/l. The acceptable conditions of the bipolar ECP unit treating the electroplating wastewater were found to be: I - 1.0 amp (or i - 6.70 amp/m2) and initial pH (pHi) of 4.5. At these acceptable conditions, the electric power and steel electrode plate consumptions were 20.0 kWh/m3 and 1.1-2.8 kg-Fe/kg Cr removed, respectively. X-ray fluorescence and X-ray diffractometric analysis performed on the precipitated sludge revealed the main compounds to be maghemite (Fe2O3) and chromite (FeCr2O4). The percent Fe2O3 and FeCr2O4 contents of the dried ECP sludge were 68% and 25%, respectively. From the mass balance analysis, the percent of Cr removal by precipitation in the ECP unit and adsorption on the ECP sludge were 85.1 and 14.8%, respectively.

Application of image analysis in activated sludge to evaluate correlations between settleability and features of flocs and filamentous species

2009 ◽  
Vol 59 (10) ◽  
pp. 2029-2036 ◽  
Author(s):  
A. Arelli ◽  
L. Luccarini ◽  
P. Madoni
Keyword(s):  
Image Analysis ◽  
Activated Sludge ◽  
Nutrient Deficiency ◽  
Domestic Wastewater ◽  
Threshold Value ◽  
Pilot Scale ◽  
Volume Index ◽  
Morphological Parameters ◽  
Treatment Processes ◽  
Sludge Properties

Digital image analysis is a useful tool to estimate some morphological parameters of flocs and filamentous species in activated sludge wastewater treatment processes. In this work we found the correlation between some morphological parameters and sludge volume index (SVI). The sludge was taken from a pilot—scale activated sludge plant, owned by ENEA, located side stream to the Trebbo di Reno (Bologna, Italy) municipal WWTP and fed by domestic wastewater. In order to use image analysis, we developed a correct method to acquire digital microbiological observations and to obtain images altogether representative of the sludge properties. We identified and assessed the parameters needed to estimate the settleability of the sludge and evaluated the morphological filamentous features. It is known that several conditions (i.e. low F/M, nutrient deficiency, low dissolved oxygen) select specific filamentous species and their excessive growth decrease floc-forming/filaments ratio, correspond to the worse settleability properties; we found a relationship between the relative abundance of filamentous species and SVI. We also evaluated the fractal dimension parameter (FD) and determined a threshold value useful to distinguish between the “weak” and “firm” floc and we found a correlation between FD and SVI.

scholarly journals Mathematical modelling of electrical potential difference in a non-uniform electric field

2020 ◽  
pp. 64-72
Author(s):  
Mustafa Erol ◽  
İldahan Özdeyiş Çolak
Keyword(s):  
Electric Field ◽  
Mathematical Modelling ◽  
Electric Fields ◽  
Electrical Potential ◽  
Potential Difference ◽  
Uniform Electric Field ◽  
Electrical Potential Difference ◽  
Dc Power ◽  
Scalar Products ◽  
Modelling Process

This work offers an unproblematic teaching tool for the instruction of challeng-ing concept of electric potential difference in a non-uniform electric field. Specifically, mathematical modelling process is employed and managed to comprehend and teach exceedingly difficult concepts of uniform and non-uniform electric fields, electrical potential difference, scalar products of vectors and also concept of path integral. In order to accomplish those tasks, initially a basic conducting panel/sheet, that is simply a wet cardboard, is designed as a part of the apparatus, together with a dc power supply, a multi meter and connecting cables. The established method is interesting in the sense that the 3D wet cardboard is novel, very practical and minimal costing, hence the approach offers physics educators fresh teaching routes and opportunities to clarify the puzzling concept of electrical potential difference and further.

Research on Micro-Electrolysis Method to Treat the Copper-Containing Electroplating Wastewater

2013 ◽  
Vol 864-867 ◽  
pp. 1560-1563
Author(s):  
Yi Ting Zhang ◽  
Hai Bo Lun
Keyword(s):  
Wastewater Treatment ◽  
Reaction Time ◽  
Total Mass ◽  
Removal Rate ◽  
Mass Ratio ◽  
Experimental Conditions ◽  
Electroplating Wastewater ◽  
Initial Ph ◽  
Carbon Mass ◽  
Electrolysis Method

Iron-carbon micro-electrolysis was applied in the treatment of the electroplating wastewater containing copper, and the parameters that affected the efficiencies of the wastewater treatment had been discussed, The results indicated that the optimal experimental conditions were initial pH 4, stirring speed 100r/min, total mass of iron and carbon 4g/0.1L, iron carbon mass ratio of 1, reaction time was 40min. The removal rate of the Cu2+was 99% or more, the effluent can meet emissions standards

scholarly journals Comparative Analysis of the Behaviour of Marine Litter in Thermochemical Waste Treatment Processes

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 13
Author(s):  
Johann Hee ◽  
Kai Schlögel ◽  
Simone Lechthaler ◽  
Jacqueline Plaster ◽  
Kristina Bitter ◽  
...  
Keyword(s):  
Waste Treatment ◽  
Treatment Options ◽  
Thermochemical Treatment ◽  
Fluorescence Analysis ◽  
Chemical Recycling ◽  
Marine Litter ◽  
Treatment Processes ◽  
Pyrolysis Condensate ◽  
Thermochemical Processes ◽  
Do So

Plastic in the ocean, especially plastic on the ocean surface is not only researched intensively but also photos and reports rise awareness of the challenge in the general public. While research is concerned with the fate of marine litter in the environment, recycling of these materials after collection is rarely addressed, mainly because there is neither considerable data on composition nor a suggested process to do so. This study is the first to analyse and evaluate chemical recycling (pyrolysis, gasification) and energy recovery (incineration) of marine litter. Two heterogenous marine litter samples from Sylt and Norderney, North Sea, Germany, were analysed, consisting of six different material groups. Agricultural mulch foil was used as reference material. The thermochemical treatment processes were reproduced by thermogravimetric analysis. Furthermore, pyrolysis trials on a semi-technical scale were conducted and the residues were analysed by proximate, ultimate and X-ray fluorescence analysis. The results indicate that heterogeneous and weathered material mixtures can be treated by thermochemical processes. Finally, the pyrolysis condensates are discussed as substrate for biotechnological upcycling. In summary, we present a comprehensive approach from the material characterisation of marine litter to the analysis of three different thermochemical treatment processes and the possibility to use the generated pyrolysis condensate for subsequent upcycling. The data collected form the basis for the evaluation and application of possible treatment options for the collected marine litter.

scholarly journals ASPECTS REGARDING THE ELECTROCOAGULATION APPLICATIONS IN THE WATER AND WASTEWATER TREATMENT

2016 ◽  
Vol 21 (2) ◽  
Author(s):  
AIDA DERMOUCHI ◽  
BENCHEIKH-LEHOCINE MOSSAAB ◽  
SIHEM ARRIS ◽  
VALENTIN NEDEFF ◽  
NARCIS BARSAN
Keyword(s):  
Wastewater Treatment ◽  
Electrode Materials ◽  
Treatment Time ◽  
Oxygen Demand ◽  
Water And Wastewater Treatment ◽  
Treatment Processes ◽  
Initial Ph ◽  
Water And Wastewater ◽  
Dc Current ◽  
Density Treatment

Electrocoagulation (EC) has been known for over a century. Applications in industry as water and wastewater treatment processes were adapted for the removal of suspended solids, organic compounds, COD (Chemical oxygen demand), BOD (biochemical oxygen demand), metallic and non-metallic pollution. The main advantage in EC technology is the fact that it works without the addition of chemical products. The DC current between metallic electrodes immersed in the effluent is used as an energy source for this technique, which causes their dissolution. The effect of the main parameters, current density, treatment time, initial pH, temperature, electrode materials, conductivity and distance between the electrodes were investigated. According to the conclusion of the works published in recent years, the removal efficiencies of pollutants materials by EC process are very important.

scholarly journals Biosolubilization of Cr (VI) from Tannery Sludge: Process Modeling, Optimization, Rate Kinetics and Thermodynamics Aspects

2019 ◽  
Vol 8 (4) ◽  
pp. 4808-4816
Keyword(s):  
Reaction Rate Constant ◽  
Polynomial Model ◽  
Main Process ◽  
Tannery Sludge ◽  
Leather Processing ◽  
Chrome Tanning ◽  
Initial Ph ◽  
Rate Kinetics ◽  
The Impact ◽  
Cr Removal

Leather is one among the significant commodities carry extensive fare profit to the Federal Democratic Republic of Ethiopia. In leather industries, chrome tanning is one of the main process for producing less susceptible to decomposition and more durable leather. Chrome tanning results in a huge amount of Cr content toxic sludge waste which poses a risk to the earth. In the present work, the optimization process parameters, initial pH, temperature, and elemental sulfur (S0 ) concentration were examined by Response Surface Methodology (RSM) for the bacterial evacuation (bioleaching) of Cr from the tannery sludge. From the RSM analysis, an equation of polynomial model was produced for the Cr removal effectiveness. Further, the optimized parameters have been recognized by solving the polynomial model through RSM. So as to get the worldwide optimized conditions, the model was settled using a technique dependent on a MATLAB tool, Genetic Algorithm (GA). Moreover, an investigation was led at various temperatures with fixed optimized initial pH and S0 concentration to assess the impact of temperature on the Cr removal by bioleaching. Using these exploratory outcomes, the kinetics for the activation energy, reaction rate-constant, rate-controlling step, and thermodynamic parameters were resolved. Such a study will be useful for designing and building up the ideal bioleaching system for sludge detoxification in leather processing industries.

Dependence of Microcrystalline Silicon Growth on Ion Flux at the Substrate Surface in a Saddle Field PECVD

2005 ◽  
Vol 862 ◽  
Author(s):  
Erik Johnson ◽  
Nazir P. Kherani ◽  
Stefan Zukotynski
Keyword(s):  
Substrate Surface ◽  
Electrical Potential ◽  
Microcrystalline Silicon ◽  
Hydrogenated Silicon ◽  
Raman Scattering Spectroscopy ◽  
The Past ◽  
Silicon Thin Films ◽  
Dc Power ◽  
Silicon Growth ◽  
The Relationship

AbstractThe Saddle-Field Glow Discharge PECVD system emulates RF-like excitation using a semi-transparent anode and a DC power supply. It has been used to deposit high quality amorphous and microcrystalline hydrogenated silicon thin films in the past. The growth of microcrystalline material is particularly sensitive to the conditions under which it is produced. Significant levels of microcrystallinity are only produced under conditions of higher pressure and electrical isolation of the substrate surface from the grounded substrate holder. We present results of a study on the relationship between substrate electrical potential and microcrystalline growth, as quantified by Raman scattering spectroscopy, at growth pressures near the minimum required for microcrystalline growth.

scholarly journals Phytoremediation of Chromium and some chemical parameters from Tannery effluent by using water Hyacinth (Eichhornia craassipes)

2017 ◽  
Vol 4 (3) ◽  
pp. 151-156 ◽  
Author(s):  
Trina Chakrabarty ◽  
Rezuana Afrin ◽  
Md Younus Mia ◽  
Md Zakir Hossen
Keyword(s):  
Water Hyacinth ◽  
Eichhornia Crassipes ◽  
High Efficiency ◽  
Reduction Rate ◽  
Alkaline Condition ◽  
Tannery Effluent ◽  
Major Focus ◽  
Chemical Parameters ◽  
Treatment Processes ◽  
Cr Removal

The present study was conducted to explore the efficiency of water hyacinth (Eichhornia crassipes) to cleanup of tannery effluent in terms of pH, TDS, EC, BOD and most importantly Cr. The study period was from November, 2013 to April, 2014. After 7 days of treatment by water hyacinth, the removal rates were: 68.15% for BOD, 59.82% for TDS and 46.56% for EC, where the corresponding rates after 15 days were: 81.73% for BOD, 67.15% for TDS and 61.93% for EC. After treatment with water hyacinth, pH of effluent reached to nearly neutral level from alkaline condition. In this study, major focus was on Cr removal and the treatment of tannery effluent using water hyacinth resulted in 32.42% reduction of Cr after 7 days and 54.72% after 15 days. The present results revealed that water hyacinth had the strong capability of absorbing Cr. On the other hand, the reduction rates after 15 days for sedimentation were: 54.23% for BOD, 30.21% for TDS, 22.28% for EC and 14.37% for Cr. After comparing the two treatment processes, it was found that the reduction rate by phytoremediation process was much higher than that of sedimentation process. This result reflected the high efficiency of water hyacinth to reduce pollutant especially Cr from tannery effluent as eco-friendly sustainable technology.Res. Agric., Livest. Fish.4(3): 151-156, December 2017

scholarly journals Engineered electrocoagulation reactor for the removal of E. coli from wastewaters

2021 ◽  
Vol 877 (1) ◽  
pp. 012048
Author(s):  
Eman A. Al-Imara ◽  
Rand L. Al-Jaryan ◽  
Sabrean F. Jawad ◽  
Mohanad M. Kareem ◽  
Hayfaa A. Mubarak
Keyword(s):  
Biocontrol Agent ◽  
Ph Value ◽  
Low Cost ◽  
Sewage Treatment ◽  
Treatment Plant ◽  
Steel Plates ◽  
E Coli ◽  
Initial Ph ◽  
Treatment And Disposal ◽  
A Current

Abstract As a consequence of natural pollution, water and sewage are polluted in many nations across the globe. Especially in poorer countries, sewage treatment and disposal practices are often substandard. Throughout many limited-income nations, the poor economic condition and absence of resources assistance severely hamper the planning and application of novel water and sewage systems. This has resulted in a rise in the number of bio-contaminants in the environment. The objective of this study is to use electrocoagulation as a low-cost method to remove or lower the amount of bio contaminant in sewage. By transmitting a voltage between the two conductors, disinfectants are generated in place. Sewerage samples were obtained at the Kerbala wastewater treatment plant, which is situated south of Kerbala, Iraq. In this work, steel plates were utilized to create coagulants. Furthermore, the effect of many factors on the performance of the electrolysis device was studied, namely spacing among electrodes and current density. The analysis indicates after 40 min of irradiation employing electrodes spaced 5mm apart and a current intensity of 2 mA/cm2, the E. coli bacteria as a biocontrol agent were killed. Furthermore, the results demonstrated that an initial pH value of 6.0 is appropriate for bio-contaminants removal utilizing electrocoagulation.

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