Jason Koutoudis Mingze Niu Arsenic Team Faculty Advisors Professors Lion and WeberShirk Student Advisors Casey Garland and Will Pennock Why Study Arsenic Common global groundwater contaminant ID: 1037655
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1. Tanapong Jiarathanakul, Jason Koutoudis, Mingze NiuArsenic TeamFaculty Advisors: Professors Lion and Weber-ShirkStudent Advisors: Casey Garland and Will Pennock
2. Why Study Arsenic?Common global groundwater contaminant
3. Why Study Arsenic?High toxicityLung and lymphatic cancerNervous, circulatory, digestive and respiratory system damageEffects on skin, liver, kidneys and eyes
4. Why Study Arsenic?International Agency for Research on Cancer (IARC) recognizes arsenic and arsenic compounds as Group 1 CarcinogenEPA and FDA set maximum arsenic concentration in drinking water at 10 ppb
5. Our GoalsDetermine the effectiveness of arsenic removal through filtration/coagulationImplement full-scale experiment using sand column with continuous flowFactors:Coagulant typeCoagulant concentrationTurbidityBed depthResidence time
6. GFAASGraphite Furnace Atomic Absorption Spectrometer
7. GFAAS
8. GFAAS
9. GFAAS
10. GFAAS
11. GFAASHow much volume of sample is taken up by the autosampler?2 L20 L200 L2 mL
12. GFAASHow much volume of sample is taken up by the autosampler?2 L20 L200 L2 mL
13. GFAAS
14. GFAASWhat temperature is used to heat the sample?100 C750 C 2500 C 5000 C
15. GFAASWhat temperature is used to heat the sample?C) 2500 C To put things in perspective:Earth’s mantle temperature range from 500 C to 4000 C .
16. Calibration Curve
17. Characteristic Mass
18. Design of Filter Column
19. Filter Column DesignA 1.5 cm (inner) diameter column will be used at a height of approximately 0.75cm to minimize effluent volume and allow high residence time.The influent groundwater will be sent in upflow stream
20. Filter Column DesignApproach velocity V= 1mm/sResidence timet = 500sEffluent volume after 1 dayQ = 17 L/dayMin upflow fluidization velocityVf= 2.4mm/s
21. Filter Column DesignProblems to Address:Unwanted fluidization due to clogging by coagulant Preferred height to operate smoothlyBackwashing concerns
22. Experimental Procedure
23. Experimental ProcedureArsenic stock solution has a concentration of 1,000 mg/L with 2% nitric acidPrepare ground water (pH about 8)1. Sodium nitrate (5.289 mg/L)2. Sodium bicarbonate (252 mg/L)3. Sodium phosphate monohydrate (0.00699 mg/L)4. Sodium fluoride (2.22 mg/L)5. Disodium metasillicate nona-hydrate (35.32 mg/L)6. Magnesium sulfate heptahydrate (62.6 mg/L)7. Calcium chloride dehydrate (111.1 mg/L)
24. Experimental ProcedureDesign experimental procedure before testing arsenicEnsure cycles run as expected, coagulant is well distributedCoagulant distribution at different upflow velocities, use dyed color
25. Experimental ProcedureUsed predetermined procedures to test the different factors on arsenic removal efficiencyTypes of coagulantCoagulant pretreatment vs. co-treatmentpH level Upflow velocity Arsenic influent concentration
26. Experimental ProcedureTypes of coagulantSand media can be coated with various types of coagulant to find the best removalFrom literature review, Iron oxide-coated has a high arsenic removal efficiencyAguaClara uses aluminum-based coagulant
27. Experimental ProcedureCoagulant pre-treatmentPre-treating the media with coagulantCoagulant co-treatmentAdding coagulant concurrently to the influent while filter runs at the normal upflow velocity for arsenic removal
28. Experimental ProcedureInteractive QuestionWhat pH level do you think has the highest arsenic removal efficiency?
29. Experimental ProcedurepH levelAt pH below 7.5, the removal percent increases with increasing of pHAt pH above 7.5, removal decreases slightly, but remains high constant efficiency Gupta, V.K., Saini, V.K., Jain, N. Adsorption of As(III) from aqueous solutions by iron oxide-coated sand, Journal of Colloid and Interface Science 288 (2005) 55–60
30. Experimental ProcedureUpflow velocity (contact time)The effect of contact time is also important The removal percent goes up with contact time up to 97% removal at longer residence timesGupta, V.K., Saini, V.K., Jain, N. Adsorption of As(III) from aqueous solutions by iron oxide-coated sand, Journal of Colloid and Interface Science 288 (2005) 55–60
31. Experimental ProcedureArsenic influent concentrationAt low concentration(100 ug/L), removal percent is high (99%)When the concentration increases, percent decreases to 75% at initial conc 800 ug/L Gupta, V.K., Saini, V.K., Jain, N. Adsorption of As(III) from aqueous solutions by iron oxide-coated sand, Journal of Colloid and Interface Science 288 (2005) 55–60
32. Experimental ProcedureClean the column and examine the reversibility of arsenic precipitation by backwashIf still has time remaining, will test the other two factors:TemperatureArsenic oxidation state
33. Future TasksFabricate the sand columnCreate calibration curve with lower concentration rangeTest the effect of nitric acidDevelop further the experimental procedure
34. Thank you!Team Arsenic : “Working Harder to Keep Arsenic out of Your Water”