Chemical, Structural and Elemental Characterization of Biosorbents Using FE-SEM, SEM-EDX, XRD/XRPD and ATR-FTIR Techniques

Abstract

The chemical, structural, and elemental composition of any adsorbents plays undoubtedly crucial role and has paramount significance in adsorption process. The present study of chemical, structural, and elemental characterization of powdered Pinus densiflora pine cones, lignite and coconut shell-based activated carbon fiber (ACF), and powdered oyster shell prior employed for anionic surfactant sodium dodecyl sulfate (SDS) adsorption was undertaken using field emission scanning electron microscope (FE-SEM), scanning electron microscope coupled with energy dispersive x-ray (SEM-EDX), X-ray diffraction/X-ray powder diffraction (XRD/XRPD), and multiple internal reflectance (MIR) or attenuated transform reflectance -fourier transform infrared spectroscopy (ATR-FTIR) techniques. The FE-SEM imaging observed at three different magnifications depicted the change in surface texture of aforementioned biosorbents before and after SDS adsorption. SEM-EDX analysis indicated alteration in the concentration and distribution of different compositional elements. The XRD analysis suggested the amorphous character in lignite and coconut shell-based ACF and powdered Pinus densiflora cones, whilst indicating the sample of powdered oyster shell to be crystalline in nature and entirely composed of CaCO 3 with the very trivial amount of impurities. Further, infrared (IR) spectroscopy demonstrated variation in IR spectra of the samples prior to and after surfactant adsorption and also further suggested occurrence of complexing or (complexation) process between ionizable functional groups and DS -or Na + ions of SDS. In addition, iodine number of the lignite and coconut shell-based ACF, powdered Pinus densiflora cones, and powdered oyster shell were found to be 285.86 mg/g, 25.01 mg/g, and 28.48 mg/g, respectively.

Evaluation of removal efficiency of phenol from synthetic aqueous solutions by Citrullus colocynthis seed ash

“…The distribution of atoms within the lattice determines the peaks' intensities. As seen in Figure 2, the two broad diffraction peaks observed at around 18° and 22° vividly show that the adsorption process made little change in the surface structure of the adsorbent (27) and included compounds such as C 18 …”

“…XRD provides information on crystal structure and texture, phase, mean grain size, crystallinity, strain, and crystal defects (27). The constructive interference of a monochromatic beam of X-rays that diffract at specific angles from each set of lattice planes produce XRD peaks.…”

Fucoidan extract from brown seaweed ( Sargassum echinocarpum ): molecular weight, elemental composition, selectivity and anticancer activity against breast cancer cells

“…The samples were analyzed using SEM-EDX (FEI, type Inpect S-50). Samples were air-dried, filtered through 0.65 μm paper, mounted on conductive carbon tape stubs, coated with carbon, and analyzed the microstructure and elemental compositions (Shrestha, 2016).…”

A KBr-impregnated paper substrate as a sample probe for the enhanced ATR-FTIR signal strength of anionic and non-ionic surfactants in an aqueous medium

“…The micro-structure and elemental composition of the paper before and aer the addition of AS and NS were conrmed using SEM-EDX and discussed in the ESI. † 47 The results are shown in Fig. S2(a) and (b).…”