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CIVIL ENGINEERING

CIVIL ENGINEERING. The People Serving Profession. What do Civil Engineers Do?. Areas of Study. Structural Engineering Transportation Engineering Geotechnical Engineering Construction Engineering and Management Water Resources Environmental. Water Resources. Ground water contamination

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CIVIL ENGINEERING

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  1. CIVIL ENGINEERING The People Serving Profession

  2. What do Civil Engineers Do?

  3. Areas of Study • Structural Engineering • Transportation Engineering • Geotechnical Engineering • Construction Engineering and Management • Water Resources • Environmental

  4. Water Resources • Ground water contamination • Remote sensing • Storm water management • Stream channel erosion • Flooding • Urban water resources • Water quality monitoring

  5. Environmental • Air and water • Proper management of the environment • Remediation of existing contaminants • Prevention of future contamination • Sustainable resource management At UMBC, Environmental Engineering includes water resources

  6. Traditionally • Water distribution networks • Sewage treatment plants • Drinking water treatment plants

  7. Now • Detection and modeling fate and transport of contaminants • Restoring environmental quality • Develop industrial processes for ecological preservation and enhance sustainability • http://www3.lehigh.edu/engineering/cee

  8. Why Environmental Engineering? • Appeals to girls • Help make the world a better place!

  9. Chemistry Review – Acids • Taste sour (vinegar, lemon juice) • Turn blue litmus paper red • Destroy chemical properties of bases • Conduct an electric current • Are corrosive • Can donate a proton or accept electrons to form a covalent bond with a base • pH <7

  10. Chemistry Review – Bases • Taste bitter (mustard, cough medicine) • Restore blue color to red litmus paper • Destroy chemical properties of acids • Conduct an electric current • Feel slippery • Can accept a proton or donate electrons to form a covalent bond with an acid • pH >7

  11. Strong or Weak? STRONG • Dissociates 100% in solution • The [H+] = concentration of acid • The [OH-] = concentration of base • Has a strong attraction for [H+] or [OH-] WEAK • Dissociate less than 100%

  12. Strong Acids • HCl hydrochloric acid • HNO3 nitric acid • H2SO4 sulfuric acid • HBr hydrobromic acid • HI hydroiodic acid • HClO4 perchloric acid

  13. Strong Bases • LiOH lithium hydroxide • NaOH sodium hydroxide • KOH potassium hydroxide • RbOH rubidium hydroxide • CsOH cesium hydroxide • *Ca(OH)2 calcium hydroxide • *Sr(OH)2 strontium hydroxide • *Ba(OH)2 barium hydroxide * Completely dissociate in solutions of .01 M or less

  14. Salts • The non-water product of an acid – base neutralization Example: HCl + NaOH --> NaCl + H2O

  15. pH • -log[H+] • [H+] is in molarity (M = mole/L) • Molarity the number of moles of solute dissolved in a liter of solution (solvent) • For a strong acid, [H+] = [acid] • For a strong base, [OH-] = [base] • pOH = -log[OH-] • pH + pOH = 14

  16. pH Examples Strong Acids • 0.10 M solution of HCl pH = - log (0.100) = 1.00 • 1.00 M solution of HBr pH = - log (1.00) = 0.00 • 2.00 M solution of HCl pH = - log (2.00) = -0.30 Strong Bases • 0.10 M solution of NaOH pOH = - log (0.100) = 1.00 pH = 14.00 – 1.00 = 13.00 • 0.050 M solution of KOH pOH = - log (0.050) = 1.30 pH = 14.00 – 1.30 = 12.70

  17. Law of Chemical Equilibrium aA + bB cC +dD [C]c[D]d = Ke [A]a[B]b Ke = equilibrium constant a, b, c, d = stochiometric coefficients

  18. Equilibrium Constant • Ke measures the extent to which a reaction goes before equilibrium is attained • The larger the Ke: • the larger the quantity of products • The more complete the reaction

  19. Calculating the pH • HAc + H2O H3O+ + Ac- (Ac = CH3COOH) • Ka = ( [H3O+ ][Ac-] ) / [HAc] = 1.77 x 10-5 • [H3O+ ] = x and [Ac-] = x because of the one-to-one molar ratio • 1.77 x 10-5 = {(x) (x)} / [HAc] • [HAc] started at 0.100 M ended at (0.100 – x) as HAc molecules dissociated • 1.77 x 10-5 = ((x) (x)) / (0.100-x) solve with the quadratic formula • Or approximate: since x is small, (0.100 – x) appr. equals 0.100 • 1.77 x 10-5 = x2 / 0.100 • x2 = 1.77 x 10-6 • x = 1.33 x 10-3 M = [H3O+] = [H+] • pH = -log(1.33 x 10-3) • pH = 2.87 http://dbhs.wvusd.k12.ca.us/webdocs/AcidBase/AcidBase.html

  20. Titration Curves • Show how the pH of a solution changes with the addition of a standard solution of base or acid • Use an acid or base of a known concentration to determine the concentration of an unknown solution • Determine the number of active sites on a solid that can adsorb a contaminant

  21. Titration of an Acid

  22. Filtration System • Combines carbon filtration with ion exchange and sub-micron filtration • Significantly reduces: • Chlorine • Lead • Synthetic chemicals • Volatile organic compounds • Turbidity • Water-borne parasites

  23. Three Step Process • Vacuum Filtration - removal of solids • Granular Activated Carbon - adsorbs molecular organic and inorganic contaminants (metals) • High pressure membrane filtration -removes ions

  24. Experiment • Test pH of water before filtration • Base and acid • Titrate solution • Filter solids • Add granular activated carbon (GAC) • Filter out GAC • Repeat titration

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