Technology for removal of humic acid

Patent filing no.: 1058/KOL/2014

Technology title: Chitosan coated iron-oxide- polyacrylonitrile mixed matrix membrane for removal of humic acid

1. Brief description of the technology

            The proposed invention relates to the fabrication of mixed matrix membrane (MMM) using iron oxide nanoparticles and polyacrylonitrile (PAN) coated with chitosan which is used for removal of humic acid from surface water. Typical humic acid concentration in surface water is up to 50 mg/l whereas in drinking water EPA imposed limit is 2 mg/l. The composition of the membrane was 15 wt% PAN, 0.4 wt% iron oxide and rest was solvent dimethylformamide (DMF). The molecular weight cut off of this membrane was 44 kDa. The membrane was tested at different concentration of synthetic humic acid as well as pond water. The range of operating conditions for was 276 kPa to 550 kPa and 40 to 80 l/h cross flow rate. The filtered water produced was in the range of 15 to 25 l/m²h and total humic acid concentration in filtrate reached below permissible limit i.e., 2 mg/l. The process does not need addition of external additives or catalysts and process throughput is high.

2. Commercial aspects of the technology & industries benefiting from it:

1.     Waste water treatment plant, as an annexure to the main operating section of various plants.

2.     Scaled-up filter for domestic and industrial use.

      3.   Advantages

·         Unique formulation of membrane removes humic acid.

·         Concentration of humic acid in the treated water was reduced below 2 mg/l (EPA limit).

·         Iron oxide nanoparticles are inexpensive thereby, reducing the operating cost.

·         Any post processing step is not required.

·         Selective adsorption of humic acid, microorganisms and filtration of larger particles are attained in a single step.

       4.  A summary of the technical details involved

1.     Composition of base mixed matrix membrane:

a)     15 wt% coated polyacrylonitrile (PAN);

b)    iron oxide in an amount ranging from 0.4 wt%; and

c)     solvent dimethyl formamide (DMF) in an amount ranging from 84.6  wt%.

2.     Composition of chitosan coating:

a)     1 to 5 wt% chitosan in 1 to 6 vol% acetic acid;

b)    Glutaraldehyde in an amount of 0.1%;

c)     NaOH in an amount ranging from 0.5 to 1 N.

        5. Future prospects of the technology

 1.     Possible use in waste water treatment plant.

 2.     Development of scaled-up filter for domestic and industrial use.

Inventors: Prof. Sirshendu De, Ms. Swapna Rekha Panda, Ms. Munmun Mukherjee