arsenic removal from contaminated drinking water using activated carbon-based adsorbents produced...

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Arsenic removal from contaminated drinkingwater using activated carbon-based adsorbents

produced from biomass residues

Produced By:Leticia Abreu Reis, Mahshid Attari, Lu wang, Maggie Han, Hossein Sajjadi,

Hojatallah Seyedy Niasar

Professors: Dr. Cedric Briens Dr. Franco Berruti

Fall 2013

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Introduction

Introduction Removal techniques Adsorption Potential

biomassAvailable systemes Conclusion

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biomassAvailable systemes Conclusion

Figure 1: Cases of natural arsenic contamination in different parts of the world. Source: British Geological Survey (http://www.bgs.ac.uk/arsenic/Bangladesh/)

150 millions of people affected110 millions in East and Southeast Asia

Bangladesh, Cambodia, China, India, Laos, Myanmar, Nepal, Pakistan,Taiwan and Vietnam

35 millions in Bangladesh

http://www.bgs.ac.uk/arsenic/Bangladesh/

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Bangladesh: range of <0.5 to 3200 ppb Bangladesh: range of <0.5 to 3200 ppb

Germany (Bavaria): range of <10 to 150 ppb

Canada (British Columbia): 0.5 to 580 ppb

Argentine: 1 to 5300 ppb


biomassAvailable systems Conclusion

World Health Organization guidance value for arsenic in drinking water: 10 ppb

• Bangladesh: range of <0.5 to 3200 ppb

• Germany (Bavaria): range of <10 to 150 ppb

• Canada (British Columbia): 0.5 to 580 ppb

• Argentine: 1 to 5300 ppbFigure 2: Percentage of contaminated wells in Bangladesh. (Bangladesh Arsenic Mitigation and Water Supply Program - http://www.bwspp.org/)

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Arsenic: Why is it a problem?

• Carcinogenic related to lung, bladder and skin cancer

• Skin problems

• Blood vessels-related diseases

• Possibly related to diabetes

• Affects pregnancy causing higher abortion and stillbirth rates but also causes later chronic diseases. Figure 3: Skin problem

due to arsenic poisoning(Contamination of drinking-water by arsenic in Bangladesh: a public health emergency)

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Arsenic entering the food chain:Drinking water and indirect means

As in Groundwater

Animals, vegetables and

cropsHuman body

Figure 4: Rice, a very efficient arsenic accumulator and a fundamental nutritional source in Bangladesh.http://science.infaround.com/wp-content/uploads/2013/02/rice-wisdom-004-home

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Objectives

• Biomass residues capable of performing this removal

• Different removal techniques

• Emphasis on activated carbon

• Propositions of methods that may be used to recover the biomass after

its exhaustion during the removal process

Introduction

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Arsenic removal techniques



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Arsenic removal techniques• Oxidation/ reduction• Precipitation and coagulation• Adsorption• Solid/liquid separation• Ion exchange• Membrane• Phytoremediation• Biological removal process



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Stable in oxygen rich aerobic environments



Quality• chemical and bacteriological

System• be able to supply water in adequate quantity, throughout

different seasons

Technology• reliable, safety, no unnecessary adverse effect on environment,

institutional capability

Cost•economically feasible

Selection of an appropriate technology

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Chemistry of Arsenic and Adsorption techniques



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Stable in oxygen rich aerobic environments



As

ARSENATEPENTAVALENT (+5)

AsO43−, HAsO4

2−, H2AsO4−

ARSENITETRIVALENT (+3)

As(OH)3, As(OH)4−, AsO2OH2

− , AsO33−

Stable in oxygen rich aerobic

environments

Predominate in reducing anaerobic environments, 10 times more toxic

In different groundwater there are different ratio of arsenic speciesIn West Bengal, arsenic species in contaminated drinking water were found to be arsenate and arsenite in 1:1 ratio

Arsenic Aqueous Speciation

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Mechanism of Adsorption of Arsenic on the surface of activated carbon-based adsorbents

Based on the nature of forces existing between adsorbate molecules and adsorbent, the adsorption can be classified into two groups:

1. Physical adsorption (physisorption)- The force of attraction between adsorbate and adsorbent are Vander Waal’s forces (very weak forces; can be easily reversed)

2. Chemical adsorption (chemisorption)- The force of attraction between adsorbate and adsorbent are almost same strength as chemical bonds. (The force of attraction is very strong)- cannot be easily reversed- highly selective- single-layer process



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Why modification and activation? Pure carbon-based adsorbent can not be used unless

they are modified for sorption (The capacities of pure adsorbent are relatively poor.)

1.Microporosity 2. Surface functional groups (more selectivity)

Possible Nitrogen containing functional groups in carbonaceous materialPreproduced from Shen W, Li Z, Liu Y. Surface Chemical Functional Groups Modification of

Porous Carbon. Recent Patents Chem. Eng. 2008;1(1):27–40



Generation of activated carbon

1. Physical activation• It is less efficient (it creates less functional group on the

surface of the activated carbon with macropore structure)

2. Chemical activation:• Performed at lower temperatures (resulting in the

development of a better porous structure)• It has both mentioned characteristics (microporosity,

functional groups)



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Surface modification methods:The most properties of AC are caused by surface functional groups- Improvement of surface activity - Improvement of selectivity of AC

• Oxidization• Acid treatment• Ammonization• Impregnation• Impregnation techniques• Soaking method• Precipitation• Ultrasonic spray pyrolysis (USP)



Porous carbon spheres produced by USP method

Reproduced from: Xu, H., Guo, J., & Suslick, K. S. (2012). Porous carbon spheres from energetic carbon precursors using ultrasonic spray pyrolysis. Advanced materials (Deerfield Beach, Fla.), 24(45), 6028–33. doi:10.1002/adma.201201915.

.

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Potential biomass



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A few biomass residues…• Natural residues: Sorghum biomass、 Legume soybean、 Orange

juice residue、 Rice polish…(agricultural residues) Waste chicken feather(animal residues) tea fungus、 red soil...• Alternative feedstocks for Activated Carbon: bones、 blood、 coffee beans、 fish、 human

hairs、 nut shells、 olive stones、 petroleum coke...

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Price of some agricultural residues

Reference: Dikeman M, Fritz J, Wailes E, Gauther W, Shapouri H. Biomass from Crop Residues: Cost and Supply Estimates. (819).

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Biomass residues

Agricultural

residues

Agricultural byproducts

Animal drug

WoodTwig leaves Rice straw

Rice husk

Cow dung Poultry litter

There are many biomass residues in Bangladesh:

Focus on Bangladesh

Reference:Pelkonen P, Pappinen A. Assessment of Bioenergy Potential from Major Crop Residues and Wood Fuels in Bangladesh. 2011;1(9):1039–1051.

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Example: Cow dung in Bangladesh• a widely available marvelous resource • large quantities in rural areas• dung retains many nutrients• low-cost and user-friendly• easily implemented at household and

community levels• rich in microorganisms, which can gasify

arsenic or involved in arsenic methylation

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Available systems



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Case study

PurifAid Company:PurifAid is a not-for-profit organisation seeking to

deploy a novel water decontamination technology to solve the arsenic water crisis in Rural Bangladesh.



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DRAM filterDRAM is a Scottish water treatment system (Device for Removal and Attenuation of Multiplepollutants)DRAM can remove 95% of arsenicUsing Cork husk waste,coconut shell,rice husks waste, whisky Installation is easy, The module is inserted into a pre-existing pumped stream Waste product can be used as biofuelworks with wastewater and GroundwaterDRAM media needs to be replaced every 4-6 months,made of steel lasting 25+ yearsOperates as purely mechanicalWaste water and ground water as input DRAM Media must be incinerated via a waste plant



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Advantages of DRAM filter



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DRAM waste management system



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Conclusion



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Why Adsorption?

• Applicable for rural areas• Easy to use• Cheap• No need to energy for operation (Use gravity)• Effective (Arsenic removal up to 95%)



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What is the dilemma for adsorption method?

• Saturation of adsorbent



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Alternatives for saturated adsorbents

• Stablisation/solidification • Biological treatment• Burning• Regeneration



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Different regeneration techniques:

• Chemical• Thermal• Supercritical solvent• Microwave• Ultrasonic• Dielectric barrier discharge (DBD) plasma



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Our proposal

Microwave assisted solvent washing followed by

recovery of solvent through alkali precipitation



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Why we think our proposed novel method could be effective?

• We improved molecular diffusivity by microwave techniques• We also increase bulk convection mass transfer by solvent washing• Synergistic effect (2+2 > 4!)



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Reproduced from: Xu, C. (Charles), Donald, J., Byambajav, E., & Ohtsuka, Y. (2010). Recent advances in catalysts for hot-gas removal of tar and NH3 from biomass gasification. Fuel, 89(8), 1784–1795.

doi:10.1016/j.fuel.2010.02.014



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Positive points of our proposal:

• Less energy consumption (Microwave acts in 2-3 minutes)

• Effective because of synergistic effect• Regeneration of solvent (Through precipitation by an appropriate alkali solution)



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Thank you for your attention

arsenic removal from contaminated drinking water using activated carbon-based adsorbents produced...

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