2.4. Preparation of PPy/RHA nanocomposite
During chemical polymerization of pyrrole, electroneutrality
of the polymer matrix is maintained by incorporation of
anions of oxidant from the reaction solution. Ferric chloride
has been found to be the chemical oxidant and water has been
reported the best solvent for chemical polymerization of pyrrole.
For preparation of PPy/RHA nanocomposite, 5 g FeCl3
was added to 100 mL of water and then a uniform solution
was resulted by using magnetic mixer. Then, 1 g of rice husk
ash was added to the solution and 1 mL fresh distilled pyrrole
monomer was added to stirred solution. The reaction was carried
out for 4 h at room temperature. Consequently, the product
was filtered to separate the impurities; product was
washed several times with deionized water and dried at temperature
about 60 C in oven for 24 h.
2.5. Removal mechanism
Completely mixed batch reactor (CMBR) technique was used
to remove heavy metals, anions and COD from textile wastewater.
Adsorption experiments were performed by agitating
0.5 g of sorbents with 50 mL of textile wastewater at room
temperature in magnetic mixer with the rotating speed of
600 rpm. At the end of predetermined time intervals, the sorbate
was filtered and the concentration of heavy metals, anions
and COD was determined. All experiments were carried out
twice. Table 2 shows the characteristics of the wastewater
(wastewater was collected from the end of process (before
treatment) of El Tawfik textile factory).
Atomic absorption spectrophotometer was used for the
analysis of heavy metals and anions in aqueous solution.
Concentrations were determined after calibrating theinstrument with standards within the concentration range of
0.5–10 mg/L for all components. To measure the unknown
ions concentration in aqueous solution, the solution was
diluted to bring the concentration within the calibration range.