1 Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt 1 REMOVAL OF HEAVY METALS FROM INDUSTRIAL WATER USING ELECTRO-COAGULATION TECHNIQUE Riyad H. Al Anbari A, Jabar Albaidani B, Suuad Mahdi Alfatlawi B, and Thikra Aissa Al-Hamdani C A B C Department of Building and Construction Engineering, University of Technology- Baghdad, Iraq / Academic Visitor 27 /University of Monash, VIC, Australia Department of Civil engineering, Babylon University, Babylon, Iraq Directorate of Health /Babylon Governorate, Iraq ABSTRACT Heavy metal removal by electrocoagulation using iron electrodes material was investigated in this paper. Several working parameters, such as ph, current density and heavy metal ions concentration were studied in an attempt to achieve a higher removal capacity. A simple and efficient treatment process for removal of heavy metals is essentially necessary. The continuous flow electrocoagulation system, with reactor consists of a ladder series of twelve electrolytic cells, each cell containing stainless steel cathode and iron anode. The treatment of synthetic solutions containing Zn 2+, Cu 2+, Ni 2+, Cr 3+, Cd 2+ and Co 2+ has been investigated. Results obtained with synthetic wastewater revealed the following: - The most effective removal capacities of studied metals could be achieved when the ph was kept at ~7. - Charge loading was found to be the only variable that affected the removal efficiency significantly. - An increase of charge loading is observed for all metals ions, when current density was varied in the range ma/cm 2. - The removal efficiencies of all studied ions increased with charge loading (Qe). - The removal rate has decreased upon increasing initial concentration. - The amount of iron delivered per unit of pollutant removed is not affected by the initial concentration. - Longer electrolysis times are necessary for chromium, cadmium and cobalt removal. - Lower efficient removal of chromium compared to zinc, copper and nickel and the less efficient removal of cadmium and cobalt. - Result show that iron is very effective as sacrificial electrode material for heavy metals removal efficiency and cost points.
2 2 Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt 1. INTRODUCTION Heavy metals are strictly regulated and must be treated before being discharged in the environment. One of the most techniques has been employed for the treatment of heavy metals, is electrocoagulation. Electrocoagulation is an emerging water treatment technology that has been applied successfully to treat various wastewaters. It has been applied for treatment of potable water (Vik et al., 1984; Holt et al., 22), urban wastewater (Pouet and Grasmick, 1995), heavy metal laden wastewater (Mills, 2), restaurant wastewater (Chen et al., 2), and colored water (Jiang et al., 22). Further, electrocoagulation offers possibility of anodic oxidation and in situ generation of adsorbents (such as hydrous ferric oxides, hydroxides of aluminum). One of the most widely used electrode materials in electrocoagulation process is iron. When iron is used as anodes, upon oxidation in an electrolytic system, it produces iron hydroxide, Fe(OH)n where n = 2 or 3. Two mechanisms for the production of the metal hydroxide have been proposed (Daneshvar, 23). The aims of this paper were to investigate the effect of initial ph, initial metal ion concentrations, current density, and treatment time on the removal efficiency of zinc, copper, nickel, chromium, cadmium and cobalt using iron anodes. The Kinetic models for heavy metals removal were studied also. 2. EXPERIMENTAL WORK Synthetic solutions were prepared from reagent grade chemical without any further purification. All glassware were cleaned with water and 1 N H 2 SO 4 and then rinsed with distilled water, while, the working solutions containing heavy metals were prepared by dissolving appropriate amount of each heavy metal in tap water. Moreover, tap water was tested for the ph and alkalinity.the ph of the tap water varied from , bicarbonate alkalinity was approximately 75-8 mg/l as CaCo 3.
3 Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt 3 A continuous flow electrocoagulation process was built in lab having a device containing twelve electrolytic cells. The device consists of a ladder series of electrolytic cells containing (carbon steel) anodes and stainless-steel cathodes. Fig. (1) Photo of the experimental apparatus. Electrolytic cells iron anodes (low carbon steel, LCS) (99.5%), each of them is constructed to achieve a narrow concentric gap of about 2 mm between the central anode and the surrounding cathode as shown in figure (2). The volume of the electrolytic cells basin alone was approximately (4.5 liters). The active surface for each (27.3 cm) anode surface area is approximately (154 cm 2 ). Fig. (2) Electrolytic cell Each (27.3 cm) carries a DC current of (1. 5.5) amp and a current densities of ( ) ma/cm 2. The over all electrolytic cell pack has dimension of (3 cm) width, (43.5 cm) height and (3.5 cm) in its thickness. All the terminals of electrodes are attached to a power source by using copper strip which acts as a single anode of electrolytic cell assembly, while the outer stainless steel strip which connects the stainless-steel perforated pipe assembly acts as a cathode. The electrolytic cell assembly was operated with flow rates up to1.9 m 3 /hr. By the end of each run, the power supply was switched off and the electrolytic solution was transferred to the settling container. Without polymer addition, about (12 hours) retention time is desirable. The clarified effluent was filtered and analyzed for the
4 4 Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt improvement of its quality to specify the electrocoagulation process efficiency for each heavy metal effluents treatment. 3. RESULT AND DISCUSSION Electrode assembly is the heart of the present treatment facility. Therefore the appropriate selection of its materials is very important. The most common electrode materials for electrocoagulation are iron and aluminum. However it is usually to use iron for wastewater treatment and aluminum for water treatment because iron is relatively cheaper (Chen, 24). 3.1 Effect of ph It has been established that the initial ph (Chen et al., 2 and Do et al., 1994) is an important factor and has a considerable influence on the performance of electrocoagulation process. Generally, the ph of the medium changes during the process, as observed by other investigator (Vic et al., 1984).this change depends on the type of electrode and on initial ph. To evaluate the ph effect, a series of experiments were performed, using solutions containing each of the six heavy metals (Zn 2+, Cu 2+, Cr (VI), Ni 2+, Co 2+, Cd 2+ ) of 5 mg/l each with initial ph varying in the range (2-1). The solutions of these metals were adjusted to the desired ph for each experiment using sodium hydroxide or hydrochloric acid. As illustrated in Figure (3), the removal efficiency of zinc, copper, Cr (VI) and nickel, reached value as high as 99%, when ph is 7 and seem to be not affected by ph for zinc, copper and nickel, as long as this kept in the range between 7 and 12, in contrast a slightly decrease of the removal efficiency of chromium is observed, when the initial ph is increased above 7. The removal efficiency of cadmium and cobalt reaches a maximum of about 83% and 8% respectively when initial ph is 7 as it seems from the same figure. However as the same as chromium, when the initial ph is increased above 7, a slightly decrease of the removal efficiency of cadmium and cobalt is observed. Furthermore, it can be seen that the removal efficiency of all studied ions decreased significantly upon decreasing initial ph and there is maximum removal efficiency at the ph of 7, which is almost neutral. Therefore, it can be concluded that when ph is 7, the majority of iron complexes (coagulants) are formed and it s the optimum ph for carrying out the electrocoagulation. From the Pourbaix diagram (Pourbaix, 1974), it can be deduced that the major complexes formed at this ph are Fe (OH) 2 + and Fe(OH) 2+.
5 Final ph Removal efficincy(%) Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt Zn Cu Ni Cr Cd Co Initial ph Fig. (3) Effect of initial ph on metal ions removal by using iron anodes material. Initial concentration of Zn, Cu, Ni, Cr, Cd, Co = 5mg/l each, current density 1.35 ma/cm 2, anode surface = 1848 cm 2, time of electrolysis = 22.2 min. Using solutions of containing mixture of the six heavy metals of 5 mg /l each, Figure (4) shows that the final ph is always higher than initial ph. This may be explained by the excess of hydroxyl ions produced at the cathode in sufficiently acidic conditions (Chen et al., 2).The difference between initial and final ph values diminishes for initial ph > 7. As a result of previous discussion of the effect of ph on the removal efficiency, the initial ph was adjusted to 7 for all subsequent studies Initial ph Fig. (4) ph variation after electrocoagulation. Initial concentrations of Cu 2+, Zn 2+, Cr 3+, Co 2+, Ni 2 +, Cd 2+ = 5 mg/l each, current density = 1.35 ma/cm 2, anode surface = 1848 cm 2, time of electrolysis = 22.2 min.
6 6 Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt 3.2 Effect of current density The current density not only determines the coagulant dosage rate, but also the bubble production rate and size (Kobia et al., 23 and Holt et al., 22).Thus, this parameter should have a significant impact on pollutants removal efficiencies. A large current means a small electrocoagulation unit. However, when too large current is used, there is a high chance of wasting electrical energy in heating up water. To investigate the effect of current density on the removal efficiency, a series of experiments were carried out on solutions containing a constant pollutants loading with current density being varied from.27 ma/cm 2 to 1.35 ma/cm 2. Figures (5) to (1) show the concentrations profiles of the studied metal ions for typical electrocoagulation runs, where the initial ph was fixed at 7.The removal rate of all studied metal ions increased upon increasing current density. The highest current (1.35 ma/cm 2 ) produced the quickest removal rate, with a 99%,concentrations reduction occurring just after 6.4 min for zinc, copper and chromium and after 9 min for nickel. While the removal rate with 87% and 8% concentration reduction occurring just after 3 min for cadmium and cobalt respectively. This is ascribed to the fact that at high current, the amount of iron oxidized increased, resulting in a greater amount of precipitate for the removal of pollutants. In addition, it was demonstrated that bubbles density increases with increasing current density (Holt et al., 22), resulting in more efficient and faster removal. Moreover, it was previously shown (Khosla et al., 1991) that the bubble size decreases with increasing current density, which is beneficial to the separation process. Indeed, the amounts of iron and hydroxide ions generated at a given time, within the electrocoagulation cell are related to the current flow, using Faraday's law: m = I t M / z F (1) where I is the current intensity, t is the time, M is the molecular weight of iron or hydroxide ion (g/mol), z is the number of electrons transferred in the reaction and F is the Faraday's constant (96486 C/mol). As the current decreased, the time needed to achieve similar efficiencies increased. This expected behavior is explained by the fact that the treatment efficiency was mainly affected by charge loading (Q = I * t), as reported by Chen et al. (2). As the time progresses, the amount of oxidized iron and the required charge loading increase. However, these parameters should be kept at low level to achieve a low-cost treatment.
7 Residual concentration (mg/l) Residual concentration (mg/l) Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt ma/cm2.54 ma/cm2 1.8 ma/cm ma/cm Q(m 3 /h) Fig. (5) Effect of current density on the removal rate of Zn 2+ ions. Initial concentrations of ions = 5 mg/l, anode surface = 1848 cm ma/cm2.54 ma/cm2 1.8 ma/cm ma/cm Q(m 3 /h) Fig. (6) Effect of current density on the removal rate of Cu 2+ ions. Initial concentrations of ions = 5 mg/l, anode surface = 1848 cm 2.
8 Residual concentration (mg/l) Residual concentration (mg/l) 8 Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt ma/cm2.54 ma/cm2 1.8 ma/cm ma/cm Q(m 3 /h) Fig. (7) Effect of current density on the removal rate of Cr 3+ ions. Initial concentrations of ions = 5 mg/l, anode surface = 1848 cm ma/cm2.54 ma/cm2 1.8 ma/cm ma/cm Q(m 3 /h) Fig. (8) Effect of current density on the removal rate of Ni 3+ ions. Initial concentrations of ions = 5 mg/l, anode surface = 1848 cm 2.
9 Residual concentration (mg/l) Residual concentration (mg/l) Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt ma/cm2.54 ma/cm2 1.8 ma/cm ma/cm Q(m3/h) Fig. (9) Effect of current density on the removal rate of Cd 2+ ions. Initial concentrations of ions = 5 mg/l, anode surface = 1848 cm ma/cm2.54 ma/cm2 1.8 ma/cm ma/cm Q(m 3 /h) Fig. (1) Effect of current density on the removal rate of Co 2+ ions. Initial concentrations of ions = 5 mg/l, anode surface = 1848 cm 2. To optimize the treatment efficiency, optimum charge loading required to achieve high removal yields (residual concentration under 2 mg/l for each metal ions except cadmium and cobalt) for each metals ion, were calculated at different current densities. The results shown in Figure (11), point out that the removal rate of zinc and copper is almost three times faster than that of chromium and nickel. Indeed, the volumetric
10 Charge loading (coloumb/l) 11 Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt electrical charges ensuring 96% removal of zinc and copper were coulomb/l, while that needed to achieve the same removal efficiency of chromium and nickel was coulomb/l. For cadmium and cobalt, the optimum charge loading required to achieve 7% removal yields were calculated at different current densities. Furthermore more, as observed by other investigators(adhoum et al., 24 and Holt et al., 22), an increase of charge loading is observed for all metals ions, when current density was varied in the range ma/cm 2. At high current density, the bubble density and upwards flux increased and resulted in a faster removal of the coagulant by floatation. Hence, there is a reduction in the probability of collision between the coagulant and pollutants. The lowest current should be selected to obtain the best removal rate without increasing of cost. The removal efficiencies of all studied ions increased with charge loading (Qe). According to Faradays law, the concentration of Fe 2+ ions released from anodes can be calculated by: [Fe 2+ ] = Qe / ZF, Z = 2 for Fe 2+ (2) The Fe 2+ ions form iron hydroxide flocs to remove heavy metal ions. However, there is a critical charge loading required. Once the charge loading reaches the critical value, the effluent quality does not show significant improvement for further current increase (Chen et al., 2). Figure (12) illustrates the effect of the charge loading on removal efficiency when the current density is the lowest (.27 ma/cm 2 ). Sharp increase of removal efficiencies are clearly shown initially. The optimum charge loading should be at the end of the sharp increase stage. In this case, they are 31.6, 37 and 44.4 coulomb/l for zinc, copper and nickel respectively and it is 55.5 coulomb/l for each of chromium, cadmium and cobalt Zn2+ Cu2+ Cr3+ Ni2+ Cd2+ Co Current density (ma/cm2) Fig. (11) Effect of current density on charge loading. Initial concentration of metals ions = 5mg/l each, anode surface = 1848 cm 2.
11 Removal efficincy (%) Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt Zn2+ Cu2+ Cr3+ Ni2+ Cd2+ Co Charge loading(coulomb/l) Fig. (12) Effect of charge loading on removal efficiency. Current density =.27 ma/cm Effect of metal ion concentration In order to examine the effect of metal ion concentration on the removal rate, several solutions containing increased concentrations (5-4 mg/l) of all six heavy metals were prepared and treated.the residual concentrations of ions were measured at different times. Figures (13) to (18) show the change in the removal rate of zinc, copper, chromium, Nickel, cadmium and cobalt with initial concentration. They all showed the same trends. As expected, it appears that the removal rate has decreased upon increasing initial concentration. This induced a significant increase of charge loading required to reach residual metal concentrations below the levels admissible for effluents discharge into the sewage system (2 mg/l) for zinc, copper, chromium and nickel and which is required to reach residual concentration of (3 mg/l) for cadmium and cobalt as shown in Fig. (19). It can be observed that charge loading undergo an increase with initial concentration. This result proves that the amount of iron delivered per unit of pollutant removed is not affected by the initial concentration. In addition, the charge loading required to remove chromium to the admissible level, is higher than that required for zinc, copper and nickel. Moreover the charge loading required to reach residual concentration of (3 mg/l) of cadmium and cobalt is much more than the other. This confirmed lower efficient removal of chromium compared to zinc, copper and nickel and the less
12 Residual concentration (mg/l) Residual concentration (mg/l) 12 Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt efficient removal of cadmium and cobalt which indicated that longer electrolysis times are necessary for chromium, cadmium and cobalt removal mg/l 1 mg/l 2 mg/l 4 mg/l Time (min.) Fig. (13) Effect of initial concentration on the removal efficiency of Zn 2+ ions. Current density = 1.35 ma/cm 2, anode surface = 1848 cm mg/l 1 mg/l 2 mg/l 4 mg/l Time (min.) Fig. (14) Effect of initial concentration on the removal efficiency of Cu 2+ ions. Current density = 1.35 ma/cm 2, anode surface = 1848 cm 2.
13 Residual concentration (mg/l) Residual concentration (mg/l) Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt mg/l 1 mg/l 2 mg/l 4 mg/l Time (min.) Fig. (15) Effect of initial concentration on the removal efficiency of Ni 2+ ions. Current density = 1.35 ma/cm 2, anode surface = 1848 cm mg/l 1 mg/l 2 mg/l 4 mg/l Time (min.) Fig. (16) Effect of initial concentration on the removal efficiency of Cr 3+ ions. Current density = 1.35 ma/cm 2, surface = 1848 cm 2.
14 Rwsidual concentration (mg/l) Residual concentration (mg/l) 14 Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt mg/l 1 mg/l 2 mg/l 4 mg/l Time (min.) Fig. (17) Effect of initial concentration on the removal efficiency of Cd 2+ ions. Current density = 1.35 ma/cm 2.anode surface = 1848 cm mg/l 1 mg/l 2 mg/l 4 mg/l Time (min.) Fig. (18) Effect of initial concentration on the removal efficiency of Co 2+ ions. Current density = 1.35 ma/cm 2, surface = 1848 cm 2.
15 Charge loading (coulomb/l) Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt Zn2+ Cu2+ Ni2+ Cr3+ Cd2+ Co Initial concentration (mg/l) Fig. (19) Effect of initial concentration on the charge loadings required for an effective removal of metals,current density = 1.35 ma/cm 2, anode surface = 1848 cm 2 residual concentration for Zn, Cu, Ni, Cr < 2mg/l and for Cd, Co < 3 mg/l. 4. CONCLUSIONS This study investigate the performance of a new continuous-flow, perforated tube electrocoagulation system for treating synthetic solutions containing zinc, copper, nickel, trivalent chromium, cadmium and cobalt using iron anodes materials. The results show the following: The removal efficiency of all studied ions decreased significantly upon decreasing initial ph and maximum removal efficiency at the ph of 7. At initial ph of 7, the removal efficiency reached value as high as 99% for zinc, copper, Cr (VI) and nickel, while it is about 83% and 8% for cadmium and cobalt. The final ph is always higher than initial ph. The removal rate of all studied metal ions increased upon increasing current density. The highest current (1.35 ma/cm 2 ) produced the quickest removal rate, with a 99%,concentrations reduction occurring after 6.4 min for zinc, copper and chromium and after 9 min for nickel. While the removal rate with 87% and 8% concentration reduction occurring just after 3 min for cadmium and cobalt respectively.
16 16 Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt The removal rate of zinc and copper is three times faster than that of chromium and nickel. The volumetric electrical charges ensuring 96% removal of zinc and copper were 37, coulomb/l respectively; while to achieve the same removal efficiency for chromium and nickel was 148.1coulomb/l. For cadmium and cobalt, the charge loading to achieve 7% removal yields were 111 coulomb/l. An increase of charge loading is observed for all metals ions, when current density was varied in the range ma/cm 2. At lowest current density (.27 ma/cm 2 ), The optimum charge loading are 31.6, 37 and 44.4 coulomb/l for zinc, copper and nickel respectively and it is 55.5 coulomb /l for each of chromium, cadmium and cobalt. The removal efficiencies of all studied ions increased with charge loading (Qe). The removal rate has decreased upon increasing initial concentration. The amount of iron delivered per unit of pollutant removed is not affected by the initial concentration. Longer electrolysis times are necessary for chromium, cadmium and cobalt. REFERENCES Adhoum, N., Monser, L., Decolourization and removal of phenolic compounds from olive mill wastewater by electrocoagulation, Chemical Engineering and Processing 43 (24) Adhoum, N., Monser, L., N. Bellakhal, J. Belgaied, Treatment of electroplating wastewater containing Cu 2+, Zn 2+ and Cr(VI) by electrocoagulation, Journal of Hazardous Materials, B 112 (24) Al-Baiani, J. H., The efficiency of electrocoagulation in the treatment of water and industrial wastewater, (23), PhD thesis, University of Technology. Chen, X., Chen, G., Yue, P.L., 2. Separation of pollutants from restaurant wastewater by electrocoagulation. SepUse of the IT facilities at Monash is governed by the following policies which can be found at: Chen, X., Chen, G., Yue, P.L., Electrocoagulation and electroflotation of restaurant wastewater, J. Environ. Eng. 126 (2) Chen, X., Chen, G., Yue, P.L., 22. Investigation on the electrolysis voltage of electrocoagulation. Chemical Engineering Science 57,
17 Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt 17 Chen, G., Electrochemical technologies in wastewater treatment, Sep. Purif. Technol. 38 (24) Chen, X., Chen, G., Separation of pollutants from restaurant wastewater by electrocoagulation, Sep. Purif. Technol., 19(2) Dabrowski, A., M. Curie-Sklodowska, Adsorption and its Application in Industry and Environmental Protection, Elsevier, Daneshvar, N., H. Ashassi-Sorkhabi, A. Tizpar, Decolorization of orangeii by electrocoagulation method, Sep. Purif. Technol. 31 (23) Do, J.S., Chen, M. L., Decolourization of dye-containing solutions by electrocoagulation,j.appl.electrochem. 24 (1994) Holt, P.K., G.W. Barton, C.A. Mitchell, A step forward to understanding electrocoagulation, characterization of pollutant s fate, Sixth Congress of Chemical Engineering, Melbourne, 21. Holt, P.K., G.W. Barton, C.A. Mitchell, Mathematical analysis of a batch electrcoagulation reactor, Water Science and Technology: Water Supply, Vol. 2, No. 5-6, pp , 22. Holt, P.K., Barton, G.W., M. Wark, A.A. Mitchell, A quantitative comparison between chemical dosing and elecrtocoagulation, Colloids Surf. A Physicochem. Eng. Aspects 211 (22) Holt, P.K., Geoffrey W. Barton and Cynthia A. Mitchell, The future for electrocoagulation as a localized water treatment technology, Chemosphere, Volume 59, Issue 3, April 25, Pages 355-Khosla, N. K., S. Venkachalam, P. Sonrasundaram, Pulsed electrogeneration of bubbles for electroflotation, J. Appl. Electrochem. 21(1991) Kobya, M., Elif Senturk, Treatment of poultry slaughterhouse wastewaters by electrocoagulation, Journal of Hazardous Materials (25). Kobya, M., Can, O.T., M. Bayramoglu, Treatment of textile wastewaters by electrocoagulation using iron and aluminum electrodes, J. Hazard. Mater. B 1 (23) Mills, D., 2. A new process for electrocoagulation. J. Am. Water Works Assoc. 92 (6), Pouet, M.F., Grasmick, A., Urban wastewater treatment by electrocoagulation and flotation. Water Sci. Technol. 31, Qasim, S.R., Wastewater Treatment Plants. Planning, Design and Operation, Technomic Publishing Company Inc., Lancaster-Basel, Ratna, P. Kumar, Sanjeev Chaudhari, Removal of arsenic from water by electrocoagulation, Chemosphere 55 (24) Rajeshwar, K., J.G. Ibanez, Environmental Electrochemistry, Academic Press, UK, 1997.
18 18 Twelfth International Water Technology Conference, IWTC12 28 Alexandria, Egypt Vic, E.A., Carlson, D.A., Electrocoagulation of potable water, Water Res. 18(1984)
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DETERMINING THE MASS OF A COPPER ATOM LAB ADV.31 From Vernier Software & Technology, 2004 STANDARDS ADDRESSED 3.4.10 A Explains concepts about the structure and properties of matter. 3.4.12 A Apply concepts
WATER TREATMENT PROCESSES Effluent Primary treatment Secondary Treatment runoff Tertiary treatment Water Treatment Processes PRIMARY TREATMENT to prepare the wastewater for biological treatment Purpose
CHAPTER 3 Metals and Non-metals Multiple Choice Questions 1. Which of the following property is generally not shown by metals? (a) Electrical conduction (b) Sonorous in nature (c) Dullness (d) Ductility
Presented at 12 th IWA ASPAC Regional Conference and Exhibition, Water Beyond 2000, 5 9 November 2000, Chiangmai, THAILAND Ratana Kanluen and Sultan I. Amer AQUACHEM INC. Canton, Michigan, U.S.A. ABSTRACT
Coagulation and Flocculation Groundwater and surface water contain both dissolved and suspended particles. Coagulation and flocculation are used to separate the suspended solids portion from the water.
Two Types of Chemical Rxns Oxidation/Reduction Chapter 20 1. Exchange of Ions no change in charge/oxidation numbers Acid/Base Rxns NaOH + HCl Two Types of Chemical Rxns Precipitation Rxns Pb(NO 3 ) 2 (aq)
Discovering Electrochemical Cells Part I Electrolytic Cells Many important industrial processes PGCC CHM 102 Cell Construction e e power conductive medium What chemical species would be present in a vessel
Cautions Heavy metals, such as lead, and solutions of heavy metals may be toxic and an irritant. Purpose To determine the cell potential (E cell ) for various voltaic cells and compare the data with the
Lab Session 6, Experiment 5: Hydrogen and the Activity Series of Metals An activity series is a listing of chemical species in order of increasing (or decreasing) reactivity. Metals (be sure you can locate
THE EUROPEAN PORTABLE BATTERY ASSOCIATION Product Information Primary and Rechargeable Batteries Introduction The following document provides product information on portable primary and rechargeable batteries.
Electrochemical cells Introduction: Sudha Madhugiri D.Chem. Collin College Department of Chemistry Have you used a battery before for some purpose? I bet you have. The type of chemistry that is used in
D E P A R T M E N T O F M A T E R I A L S S C I E N C E A N D E N G I N E E R I N G M A S S A C H U S E T T S I N S T I T U T E O F T E C H N O L O G Y 3.014 Materials Laboratory Fall 2006 LABORATORY 3:
Chemistry 1C-Dr. Larson Chapter 20 Review Questions MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) is reduced in the following reaction: Cr2O7
BOD / CBOD FROM A TO Z Amy Starkey Stark County Sanitary Engineers What is BOD???? What is BOD? It is a measure of the amount of oxygen consumed by bacteria during the decomposition of organic materials.
Oxidation-Reduction Reactions What is an Oxidation-Reduction, or Redox, reaction? Oxidation-reduction reactions, or redox reactions, are technically defined as any chemical reaction in which the oxidation
Class: Date: midterm1, 2009 Record your name on the top of this exam and on the scantron form. Record the test ID letter in the top right box of the scantron form. Record all of your answers on the scantron
1 ELECTROCHEMISTRY REDOX Reduction gain of electrons Cu 2+ + 2e > Cu (s) Oxidation removal of electrons Zn (s) > Zn 2+ + 2e HALF CELLS these are systems involving oxidation or reduction there are several
United States National Risk Management Environmental Protection Research Laboratory Agency Cincinnati, OH 45268 Research and Development EPA/6/SR-97/54 August 997 Project Summary Theoretical and Experimental
Additional Lecture: TITRATION BASICS 1 Definition and Applications Titration is the incremental addition of a reagent solution (called titrant) to the analyte until the reaction is complete Common applications:
Group A Cation Analysis Inorganic Qualitative Analysis Inorganic qualitative analysis is the unambiguous identification of cations (and/or anions) which are present in a given solution. Unique tests for
Chapter 21: Electrochemistry Page 1 CHAPTER 21 ELECTROCHEMISTRY 21-1. Consider an electrochemical cell formed from a Cu(s) electrode submerged in an aqueous Cu(NO 3 ) 2 solution and a Cd(s) electrode submerged
Name AP CHEM / / Collected Essays Chapter 17 Answers 1980 - #2 M(s) + Cu 2+ (aq) M 2+ (aq) + Cu(s) For the reaction above, E = 0.740 volt at 25 C. (a) Determine the standard electrode potential for the
APPENDIX B EXAMPLE OF A COMPLETED SAMPLING PLAN WORKSHEET This example of a completed sampling plan worksheet has been included to illustrate the information necessary to document a sampling program for
Harnessing the Power in Nature Lecture Presentation Chapter 18 Electrochemistry Sherril Soman Grand Valley State University The goal of scientific research is to understand nature. Once we understand the
NUROP Congress Paper Bio-hydroleaching of Nickel-Cadmium Batteries Huang J.D. and Ting Y.P. Department of Chemical and Bio-molecular Engineering, National University of Singapore 4 Engineering Drive 4,
21 st Century Chemistry Structured Question in Topic 5 Chemical Cells and Electrolysis Unit 18-21 1. (a) Both zinc-carbon cell and silver oxide cell are primary cells. (i) Why are they classified as primary
GUIDELINES FOR LEACHATE CONTROL The term leachate refers to liquids that migrate from the waste carrying dissolved or suspended contaminants. Leachate results from precipitation entering the landfill and
5 th International & 26 th All India Manufacturing Technology, Design and Research Conference (AIMTDR 2014) December 12 th 14 th, 2014, IIT Guwahati, Assam, India Fabrication of Complex Circuit Using Electrochemical
EXPERIMENT 10: Electrical Conductivity Chem 111 INTRODUCTION A. Electrical Conductivity A substance can conduct an electrical current if it is made of positively and negatively charged particles that are
EPERIMENT 8: Activity Series (Single Displacement Reactions) PURPOSE a) Reactions of metals with acids and salt solutions b) Determine the activity of metals c) Write a balanced molecular equation, complete
Journal of ELECTRONIC MATERIALS, Vol. 36, No. 11, 2007 DOI: 10.1007/s11664-007-0270-x Ó 2007 TMS Special Issue Paper -Cu Intermetallic Grain Morphology Related to Layer Thickness MIN-HSIEN LU 1 and KER-CHANG
Cambridge International Examinations Cambridge International General Certificate of Secondary Education *0123456789* CHEMISTRY 0620/03 Paper 3 Theory (Core) For Examination from 2016 SPECIMEN PAPER 1 hour
Electrochemistry Worksheet 1. Assign oxidation numbers to each atom in the following: a. P 4 O 6 b. BiO 3 c. N 2 H 4 d. Mg(BrO 4 ) 2 e. MnSO 4 f. Mn(SO 4 ) 2 2. For each of the reactions below identify
Purpose The purpose of this experiment is to determine the equivalent mass of copper based on change in the mass of a copper electrode and the volume of hydrogen gas generated during an electrolysis reaction.
Nitrate DOC316.53.01066 Cadmium Reduction Method Method 8039 0.3 to 30.0 mg/l NO 3 N (HR) Powder Pillows or AccuVac Ampuls Scope and application: For water, wastewater and seawater. Test preparation Instrument-specific
Worksheet # 11 1. A solution of sodium chloride is mixed with a solution of lead (II) nitrate. A precipitate of lead (II) chloride results, leaving a solution of sodium nitrated. Determine the class of
EXPERIMENT 7 Reaction Stoichiometry and Percent Yield INTRODUCTION Stoichiometry calculations are about calculating the amounts of substances that react and form in a chemical reaction. The word stoichiometry
Dynamic Soil Systems Part A Soil ph and Soil Testing Objectives: To measure soil ph and observe conditions which change ph To distinguish between active acidity (soil solution ph) and exchangeable acidity
A SHORT INTRODUCTION TO CORROSION AND ITS CONTROL CORROSION OF METALS AND ITS PREVENTION WHAT IS CORROSION Corrosion is the deterioration of materials by chemical interaction with their environment. The
Cambridge International Examinations Cambridge International General Certificate of Secondary Education *0123456789* CHEMISTRY 0620/04 Paper 4 Theory (Extended) For Examination from 2016 SPECIMEN PAPER
Voltaic Cells Introduction In this lab you will first prepare a set of simple standard half-cells and then measure the voltage between the half-cells with a voltmeter. From this data you will be able to