Page 135 - AJWEP-22-6

Plantain waste for lab water cleanup

Figure 12. SEM images of PPPS
Abbreviations: SEM: Scanning electron microscopy;
PPPS: Powdered plantain pseudo-stem

Figure 11. Pseudo-second-order kinetic model for
the adsorption of Pb by PPPS
2+
Abbreviations: qe: Amount adsorbed at equilibrium; Figure 13. SEM images of the Pb adsorbed PPPS
2+
qt: Amount of adsorbate adsorbed at time t; Abbreviations: SEM: Scanning electron microscopy;
Pb: Lead; PPPS: Powdered plantain pseudo-stem Pb: Lead; PPPS: Powdered plantain pseudo-stem

3.6.1. Morphological analysis and adsorption potential particulates are likely lead complexes or precipitates,
of PPPS formed as Pb²⁺ interacts with functional groups on the
The SEM analysis (Figure 12) of PPPS reveals a rough, plant matrix. Increased roughness, pore formation,
porous surface interspersed with fibrous structures, and fiber fragmentation are also evident, indicating
significantly increasing its active surface area. This that metal ion binding may have caused localized
structural characteristic is advantageous for adsorption swelling, collapse, or chemical etching of the biomass
applications, as the increased surface exposure provides surface. These changes suggest the formation of surface
a greater number of binding sites for metal ions, thereby
improving adsorption capacity. complexes between Pb²⁺ ions and oxygen-containing
Furthermore, the observed variation in particle size and functional groups.
shape may contribute to non-uniform binding efficiency These morphological changes strongly support the
across different regions of the material. However, the hypothesis that Pb²⁺ adsorption on plantain pseudo-stem
overall adsorption potential remains high due to the occurs through a combination of surface complexation
presence of extensive surface structures available for and ion-exchange, facilitated by the natural porosity
interaction. Notably, the presence of elongated fibrous and functional groups in the biomass. The post-
structures, likely representing lignocellulosic bundles, adsorption surface damage and particle deposition are
suggests incomplete delignification, particularly if the clear indications of successful metal uptake. These
material underwent pre-treatment for fiber extraction. findings, when combined with FTIR results, suggest
Residual lignin and hemicellulose could influence the that hydroxyl, carbonyl, and ether groups play a
surface chemistry and metal ion affinity, highlighting significant role in metal binding. This underscores the
the need for further investigation into their role in adsorptive potential of plantain pseudo-stem for heavy
adsorption efficiency. metal removal from aqueous systems.

3.6.2. SEM analysis of Pb -adsorbed PPPS 3.6.3. SEM analysis of recovered PPPS
2+
After exposure to Pb²⁺ ions, the surface undergoes a The surface morphology of the recovered plantain
notable morphological transformation as shown in pseudo-stem (Figure 14) reveals a noticeably more
Figure 13. The previously defined fibrous structure porous and rough texture, resulting from the degradation
appears distorted and irregular, with amorphous of hemicellulose and partial delignification during
and granular deposits visible on the surface. These the treatment process. These structural alterations are

Volume 22 Issue 6 (2025) 129 doi: 10.36922/AJWEP025110078