Sodium hydroxiderecycling Technology focusing on Ion Selective Membrane Filtration Student: Nguyen m

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Sodium hydroxide-recycling Technology
focusing onIon Selective Membrane
FiltrationStudent Nguyen manh cuong
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Introduction

• Nowadays, membrane filtration technique is used
  widely in many fields, such as in medicines,
  pharmaceuticals, and especially in water
  treatment
• In Vietnam, application of membrane filtration
  for treatment of waste water from
  paper-manufacturing factories attracts attention
  of both producers and scientists.
• Sodium hydroxide, a main agent used in this
  process, comprises high amount of the cost of the
  whole process
• Consequently, sodium hydroxide-recycling is at
  heart of paper manufacturing

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Current technique in Vietnam for recycling sodium
hydroxide

• Burning sodium organic salts contained in the
  black liquor
• RCOONa O2 CO2 H2O Na2CO3
• Na2CO3 is separated from resulting mixture and
  then is combined with solution Ca(OH)2 to form
  NaOH
• Ca(OH)2 Na2CO3 CaCO3 2 NaOH
• However, yield of the process is low and
  byproduct of the process is CO2, a greenhouse
  effect gas.

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Application of charged nano membrane filtration
for NaOH-recycling from Black Liquor.

• First step The Black liquor is mixed with
  concentrated H2SO4 and then clarified from lignin
  by sedimentation combined with coagulation,
  flocculation.
• Second step The solution received in first step
  is carried through pretreatment unit
• Third step The solution then is applied to a
  pilot using NF negatively charged membrane where
  RCOO1-, SO42-, and carbonhydrates are rejected
  and only Na1, H3O1, and OH1- pass through the
  membrane.

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Objective of the future work

• Focusing on factors and mechanisms increasing
  yield NaOH-recycling in the process.
• Thus my task is devoted to studying factors and
  mechanisms effecting
• rejection of RCOO1-, SO42- , carbonhydrates
  and penetration of Na, H3O,
• OH - with charged nano-filtration (NF)
  membrane
• Membrane properties Hydrophobicity, pore
  size, surface charge, water
• permeability
• Water composition factors RCOOH
  concentration, pH, Na concentration
• and ionic strength.
• Filtration process conditions Flux rate and
  mass transfer in the fluid
• boundary layer.

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Perspective of the research

• My future research would be consistent with GIST
  interest in filtration Technology
• My prospective studying on membrane filtration
  Technology in GIST would be not only applied to
  the concerned problems in my country but also
  useful for industrial wastewater-treatment
  Technology in Korea.

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