Synthesis of Fe Doped Poly p-Phenylenediamine Composite: Co-Adsorption Application on Toxic Metal Ions (F- and As3+) and Microbial Disinfection in Aqueous Solution

Abstract

Water is regarded as an important natural resource to sustain life, and its purification is an important criterion that determines its quality and usefulness. In this study, the incorporation of Fe³⁺ oxide onto a phenylenediamine (pPD) polymer matrix through chemical co-polymerization was prepared, and its arsenite and fluoride removal potentials at optimal conditions from aqueous solution were evaluated. The morphology and structural analysis of the synthesized Fe-doped pPD (Fe-pPD) were comparatively evaluated using the FT-IR, SEM, EDS, and XRD techniques. Fe was successfully incorporated onto pPD matrix as confirmed by different morphological characterizations. The rate of adsorption of F^- and As³⁺ onto the Fe-pPD composite best followed the pseudo-second-order kinetic model. The experimental data for both As³⁺ and F^- onto the Fe-pPD composite better fit the Freundlich isotherm model at different operating temperatures. Overall, the synthesized composite exhibited a strong affinity towards fluoride uptake (96.6%) than arsenite uptake (71.14%) with a maximum capacity of 6.79 (F^-) and 1.86 (As³⁺) mg/g. Additionally, the synthesized adsorbent showed some level of antimicrobial activity against common water-borne bacterial. Therefore, the Fe-doped pPD composite has the potential ability for inorganic metal species pollutants remediation and bacterial disinfection in community-level water purification processes.

Keywords: adsorption experiments; arsenic and fluoride remediation; bacterial disinfection; poly para-phenylenediamine composite; water pollution.

Figure 1

Percent removal of pPD and % Fe in pPD adsorbents for As³⁺ and F⁻ uptake (initial concentration: 10 mg/L, adsorbent dose 0.4 g, and contact time 30 min at 297 K).

Figure 2

FTIR spectra of bare pPD and Fe-pPd composite.

Figure 3

SEM-EDS results: (a,b) SEM images of bare pPD and Fe-pPD; (c) EDS spectra of bare pPD; (d) Fe-pPD EDS spectra; (e) EDS spectra of the co-adsorbed As and F ions on the Fe-pPD composite.

Figure 4

XRD diffractogram of pPD and Fe-pPD composite.

Figure 5

BET adsorption and desorption plots of (a) bare pPD and (b) Fe-pPD.

Figure 6

The significance of contact time on F⁻ and As³⁺ sorption using Fe-pPD. (Initial F⁻ and As³⁺ concentration: 5 and 10 mg/L, respectively; adsorbent dose: 0.4 g; solution volume: 50 mL; shaking speed: 250 rpm at 297 K).

Figure 7

Kinetic models (a,b): pseudo-first- and second-order; (c,d): intra-particle diffusion of F⁻ and As³⁺ respectively onto the Fe-pPD composite.

Figure 8

Effect of adsorbent dose on As³⁺ and F⁻ sorption. Initial F⁻ and As³⁺ concentrations: 5 and 10 mg/L; adsorbent solution volume: 50 mL; contact time: 40 min; shaking speed: 250 rpm at 297 K.

Figure 9

Effect of initial concentrations on (a) As³⁺ and (b) F⁻ sorption at different working temperatures. Initial F⁻ and As³⁺ concentration: 5 and 10 mg/L; adsorbent dose: 0.25 g and 0.2 g; solution volume: 50 mL; contact time: 24 h; shaking speed: 250 rpm; and temperature ranges: 298–323 K.

Figure 10

(a,b) As³⁺ for Langmuir and Freundlich isotherm model plots; (c,d) F⁻ for Langmuir and Freundlich isotherm model plots.

Figure 11

Effect of pH (a) and pH_pzc (b). Initial As³⁺ and F⁻ concentration: 5 and 10 mg/L; adsorbent dose: 0.25 and 0.2 g; solution volume: 50 mL; contact time: 40 min; shaking speed: 250 rpm; and temperature: 297 K.

Figure 12

(a,b) Effect of co-existing ions plots for As³⁺ and F⁻ (initial F⁻ and As³⁺ concentration: 5 and 10 mg/L respectively; adsorbent dose: 0.25 and 0.2 g; solution volume: 50 mL; contact time: 24 h; shaking speed: 250 rpm; and temperature: 297 K).

Figure 13

Regeneration results (a) As³⁺ and (b) F⁻ (initial F⁻ and As³⁺ concentration: 5 and 10 mg/L; adsorbent dose: 0.25 and 0.2 g; solution volume: 50 mL; contact time: 40 min; shaking speed: 250 rpm; and temperature: 297 K).

Figure 14

Antimicrobial activity of the Fe-pPD composite.