ICWES15 -Comparative Absorption of Copper from Synthetic and Real Wastewater by Uncalcined Sodium Exchanged and Acid Modified Montmorillonite. Presented by Dr christianah Olakitan Ijagbemi, Akure, Nigeria
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ICWES15 -Comparative Absorption of Copper from Synthetic and Real Wastewater by Uncalcined Sodium Exchanged and Acid Modified Montmorillonite. Presented by Dr christianah Olakitan Ijagbemi, Akure, Nigeria
- 1. Christy Ijagbemi Ph. D Department of Mechanical Engineering Federal University of Technology, Akure, NIGERIA Adsorption of Copper from Synthetic and Real Wastewater by Un-calcined Sodium Exchanged and Acid Modified Montmorillonite
- 4. Hg Al Ba Pb Cd Fe Heavy Metals Toxic Heavy Metals
- 5. Heavy metals employed in some major industries (Palmer et al., 1988). Introduction Industries Cd Cr Cu Fe Hg Pb Ni Zn Pulp, paper mills, board mills x x x x x x Organic chemical, petrolchemicals x x x x x x Alkalis, inorganic chemicals x x x x x x Fertilizers x x x x x x x x Petroleum refining x x x x x x x x Basic steel work foundries x x x x x x x Motor vehicles, aircraft plating and finishing x x x x x x Steam generation power plats x x
- 9. Research goal : To develop an effective and regenerative material from MMT and evaluate its application potentials to replace activated carbon for the treatment of heavy metal- loaded industrial effluents Research idea To provide explicit information on how the physicochemical nature and behavior of a natural clay (montmorillonite - MMT) surface can be articulated for designing effective heavy metal ion treatment strategies in water and wastewater systems. Research idea and goal
- 10. To modify MMT surface properties and evaluate the effects of the modifications on adsorptive behavior of MMT for heavy metal ions removal in aqueous solutions. Research Objective
- 12. Researchers have focused on use of other relatively cheaper adsorbents to replace activated carbon Adsorption Background
- 15. Sodium montmorillonite (Na-MMT) MMT : 1 M NaCl solution = 1 g : 10 mL Mechanical stirring (24 h), repeated 5 times Centrifugation and AgNO 3 test for Cl - Drying at 105 o C for 6 h Sieving to 150 μ m Synthesis( Na-MMT) Materials and methods
- 16. Acid treated montmorillonite (A-MMT) MMT : 4 N H 2 SO 4 = 1 g : 40 mL Drying at 105 o C for 6 h Sieving to 150 μ m Synthesis (A-MMT) Materials and methods Refluxing in a shaking water bath (3 h) at 90 o C Centrifugation and BaCl 2 test for SO 4 2-
- 18. Materials and methods Chemical assay of industrial wastewater . Parameters Quality/ 4 L of effluent pH 6.1 COD 117.5 (mg) Suspended solids 57.4 (mg) Normal hexane 1.0 Total Nitrogen 57.78 Total Phosphorus 10.08 Cyanide 0.348 (mg) Copper 124.37 (mg) Nickel 60.19 (mg) Chromium 0.317 (mg)
- 20. Applied kinetic models Results and discussion Isotherm Empirical form Linear form Plot Pseudo first-order Pseudo second-order Elovich Intra-particle
- 21. Characterization of montmorillonites Results and discussion Adsorbent CEC (meq/100g ) d -spacing (nm) Surface area (m 2 /g) MMT 89.24 0.126 267 Na-MMT 94.18 0.128 286 A-MMT 57.69 0.098 190
- 22. Effect of pH Results and discussion Effect of pH on the adsorption of Cu 2+ onto Na-MMT and A-MMT (Cu 2+ concentration, 100 mg/L; adsorbent dose, 6 g/L; equilibrium time, 250 min; temperature 25 ± 0.1 °C; 200 rpm) Adsorption was highly pH dependent: imply that surface complexation contributes to Cu(II) adsorption. Na-MMT displayed a higher adsorption capability.
- 27. Results and discussion Application to real industrial wastewater Removal of Cu(II) and Ni(II) from industrial wastewater by modified montmorillonites . N.D : Not Dedectable Metals Effluent concentration/50 mL (mg/L) Remaining concentration in mg/L (% removal) Na-MMT A-MMT Zr-MMT AC Cu(II) 69.67 10.01 (85.6) 28.43 (59.2) 19.47 (72.1) 3.68 (94.7) Ni(II) 10.27 N.D N.D N.D N.D Cr(VI) 0.049 N.D N.D N.D N.D
- 28. Conclusion and recommendation The natural occurrence, availability, adsorption and regeneration capabilities, even cost, pose MMT as a substitute for activated carbon in toxic heavy metal ions treatment of industrial wastewater. The application of these modified-MMTs by industrial units using a batch stirred-tank flow reactor is hereby recommended for direct solution to problems of heavy metal-loaded wastewater discharge. The loaded MMT after several use, can be disposed off for brick making in the building industry. Conclusions
- 30. Sources and Sinks of Heavy Metals Modified – from http://pubs.usgs.gov/circ/circ1133/images/fig 21.jpeg
- 31. Route of Exposure: Absorption, Ingestion, Inhalation http:healtheffects.net/he/images/ToxTri.gif
- 32. Maximum contaminant level (MCL) of heavy metals in surface water and their toxicities (prepared from http://www.epa.gov/safewater/mcl). Heavy metal Rank Toxicities Maximum effluent discharge standards (mg/L) EPA (CERCLA, 2005) USA Cr(VI) 18 Headache, nausea, diarrhea, vomiting 0.01 Pb(II) 02 Kidney damage, renal disorder, cancer 0.015 Zn(II) 74 Depression, lethargy, neurologic signs such as seizures and ataxia, and increased thirst 5.0 Cu(II) 133 Liver damage, Wilson disease, insomnia 1.3 Cd(II) 08 Kidney damage, renal disorder 0.005 Ni(II) - Dermatitis, nausea, chronic asthma, coughing 0.20
- 33. Numbers of tested adults reported to the NYS Department of health for (A) Arsenic and (B) Lead by level (A) (B) USDA Report, 2005
- 34. Hg Al Pb Heavy Metals Toxic Heavy Metals Cu Cd Ni
- 35. Theory - ideal MMT
- 36. The amount of metal ion adsorbed per unit mass of adsorbent q t (mg/g) at each time t , by adsorbents was calculated from the mass balance expression: and the percentage removal of metal ions was obtained using: Removal (%) V = volume of metal ion solution (mL) C 0 = initial concentration of the metal ion solution (mg/L) C t = liquid-phase concentrations of the metal ion solution at any time t (mg/L) m = amount of adsorbent used (g) Adsorption Calculation
- 37. The net surface charge density, S o , was calculated using the equation above. S o = surface charge (C cm −2 ) n = numbers of moles of ions F = Faraday constant. Г H + and Г OH - = adsorbed amounts of H + and OH − ions (mol cm −2 ) during the titration process In this manner, the dependence of the surface charge density on pH and the electrolyte concentration were obtained. Calculation Surface charge density
- 39. Adsorption capacities (mg/g) of adsorbent for different heavy metals Babel, 2002 Adsorbent Cd 2+ Hg 2+ Cu 2+ Ni 2+ Zn 2+ Pb 2+ Cr 2+ Cost (kg/USD) Chistosan 815 222 164 75 273 15.43 Zeolite 2.2 1.6 0.48 0.5 1.4 3.3 0.03-0.12 Clay (smectite ) 0.04-0.12 Montmorillonite 4.72 4.98 0.68 Kaolinite 0.32 1.25 0.12 Illite 4.29 Peat 22.48 12.07 11.74 13.08 43.9 0.023 Fly ash 2.82 2.92 Activated carbon (GAC) 44.44 0.87 Cellulose 73.46 1.07 Natural oxides Aluminium oxides 31 33 11.7 Ferric oxide 72 230 Industrial waste Lignin (Black Liquor) 1865 1USD/ton Sawdust 13.80
- 40. Montmorillonite Van Olphen, 1979
- 41. Schematic picture of the montmorillonite particle (A), the top plane (basal plane) possesses exchangeable sites, whereas the edge surface dissociable ones. Parts (B) and (C) show the electrical double layer model for both kinds of planes. Duc et al., 2005
- 42. Mineral surface properties Surface charge of an oxide mineral surface in aqueous systems will change with changing pH as a function of the PZC of that mineral. Surface charge creates a surface condition in which there is an uneven charge distribution. The consumption and release of protons during an acid/base titration can be due to: – proton adsorption/desorption on the edge sites (i.e.aluminols and silanols) – exchange reactions on basal planes to compensate the negative structural charge – hydrolysis of aqueous cations released during mineral dissolution. Surface Charge Theory
- 44. Definitions of the surface charges of clays and relevant characteristic points determined from potentiometric titrations or electrokinectic measurements Acronym Name Definition Proton charge Surface charge developed by protonation- deprotonation of surface groups. Lattice charge Charge originating from lattice substitutions by lower-charge metals and giving rise to the cation exchange capacity. PZNPC Point of zero net Intersection between raw titration curve for the proton charge blank and for the suspension. PZSE Point of zero salt Intersection between charge curves at different effect electrolyte concentrations PZC Point of zero Common intersection point where both PZNPC charge and PZSE coincide. IEP Isoelectric point pH of zero ζ potential on eletrokinectic curves
- 47. Metal Ionic radius Atomic radius Na + 116 168 H + - 25 Zr 3+ 88.5 160 Ni 2+ 83 135 Cu 2+ 87 135 Al 3+ 53.5 125 Mg 2+ 86 150 Si 3+ - 110 Fe 3+ 63 140
Hinweis der Redaktion
- In the right concentrations, many metals are essential to life. In excess, these same chemicals can be poisonous. Similarly, chronic low exposures to heavy metals can have serious health effects in the long run. The main threats to human well-being are associated with lead, arsenic, cadmium and mercury, and it is these substances that are targeted by international legislative bodies.
- Transition metal is "an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell." An ion is an atom or molecule which has lost or gained one or more valence electrons , giving it a positive or negative electrical charge. A negatively charged ion , which has more electrons in its electron shells than it has protons in its nuclei , and is known as an anion A positively-charged ion , which has fewer electrons than protons, is known as a cation Metallic bonding is the electrostatic attraction between delocalized electrons , and the metallic nuclei within metals . It involves the sharing of free electrons among a lattice of positively-charged metal ions. Chelation therapy is a series of intravenous infusions containing EDTA and various other substances. EDTA is a polyamino carboxylic acid The first widely used chelating agent, the organic dithiol compound dimercaprol (also named British Anti-Lewisite or BAL), was used as an antidote to the arsenic-based poison gas,
- Distill water – for proton adsorption Charge determination (KCl solution) Initial pH values (pH i ) of 20 mL of KCl solutions (concentrations 10 −3 and 10 −2 M) were adjusted in pH range of 3.1–10 using 0.01 M of HCl or NaOH. Then, 0.05 g of MMT was added to each sample. Equilibration was carried out by shaking, in a rotary incubator at 200 rpm for 2 h at 25±1 ◦ C. The dispersions were then filtered and the final pH of the solutions (pH f ) was determined, point of zero charge was found from a plot of pH f vs. pH i . Each addition of 0.05 g of dry MMT sample were added to 30mL of KCl solution at a given ionic strength, I = 0.01M, having a pH between 2.4 and 5.1. After each addition, the pH was recorded after an equilibrium time. It was verified that the pH reached a constant value for exactly 10min after each addition of the mineral. Then, a new amount of sample was introduced to change the pH; this procedure was repeated until a pH was found where no pH change occurs with further addition of the sample. For a clay or oxide free of contamination (Zalac and Kallay, 1992), this pH value has been shown to be a good approximation to the PZNC of oxide or clay surfaces.
- silver nitrate + dilute nitric acid.) Cl ions give a white precipitate with silver nitrate.
- barium chloride + zinc sulfate , in the presence of HCl - zinc chloride + barium sulfate. (white precipitate) BaCl 2(aq) + ZnSO 4(aq) ZnCl 2(aq) + BaSO 4(s)
- CEC : The pH 7.0 ammonium acetate procedure of Chapman (1965) is recommended. NH 4 + saturation: the soil is saturated with NH 4 +, then the NH 4 + is replaced by Ca++, and lastly the NH 4 + removed is measured to determine the number of exchange sites that were occupied by ammonium. To estimate the actual CEC (at the pH of the soil), the sum of cations extracted by a routine Soil test (CECe) should suffice. For a very precise measure of CEC, the BaCl 2 -compulsive exchange procedure is suggested (Gillman, 1979, Gillman and Sumpter, 1986; Rhoades, 1982). EGME : placed in vacuum desicator containing diphosphorus pentaoxide for 4hrs to remove moisture from the surface. Dried adsorbent is weighed. Excess amt of ethlene glycol monoethyl ether (EGME) was applied to wet adsorbent surface. And then placed in a vacuum again containing calcium chloride. Weight of EGME remaining as a function of time was ploted. Equilibrium weight of EGME for monolayer coverage was obtained.
- With Mg 2+ substituting for Al 3+ there are fewer positive charges to neutralize the negative charges and a large permanent (negative) charge results (it is called permanent charge since it takes place during crystallization and it is not a subject to changes). In contrast, there are also variable or pH-dependent charges that are formed by protonation and deprotonation of functional groups like -OH.
- " charge density " defined as: the number of charges on the cation divided by it’s surface area