Elemental composition of membrane foulant layers using EDS, XPS, and RBS

Abstract

Existing studies investigating the elemental composition of membrane foulant layers typically use one of the following analytical techniques: energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), or Rutherford backscattering spectrometry (RBS). However, given that EDS, XPS, and RBS have different capabilities, limitations, and depths of analysis, these techniques may provide differing results from each other. Thus, to understand the suitability of each technique for the analysis of membrane foulant layers, a thorough study is needed that compares EDS, XPS, and RBS results for a diverse set of fouled membranes. As such, the objectives of this study were to identify the strengths, weaknesses, and limitations of EDS, XPS and RBS in the characterization of the elemental composition of foulant layers, and evaluate whether the three techniques yield consistent and/or complementary results for sample composition and structure. We studied four diverse fouled membranes, each before and after cleaning, as well as the original unfouled membranes, and assessed the suitability of each technique for various applications, such as the detection of major elements in thick and thin layers, characterization of sample depth heterogeneity, evaluation of overall membrane cleaning efficacy, among others. Results show that in the analysis of membranes and foulant layers: (i) applying a single technique may lead to incomplete or incorrect conclusions about composition or structure; (ii) RBS is the most advantageous technique for elemental analysis; (iii) EDS has important limitations, but is appropriate for evaluating overall elemental composition of foulant

Facile Synthesis of Porous Flower‐Like Co3O4‐SiO2 Composite for Catalytic Decoloration of Rhodamine B

“…Determined by the quantitative XPS analysis, the molar ratio of Si to Co is roughly 8.0, which is much higher than that observed from bulk EDX analysis (1.28, see below in Table ). Since analysis depth of the XPS measurement is within several nanometers, it is conclusive that most of the SiO 2 is on the surface of the composite . For the sample prepared without silica (Figure , line b), the Co 2p 3/2 peak is located at 780.1 eV, consisting with the value of pure Co 3 O 4 .…”

“…Based on the major (311) diffraction peak centered at 36.8 o , the average crystallite size of Co 3 O 4 in each sample is calculated by using the Scherrer equation. As shown in Table , the value for the pure Co 3 O 4 prepared without silica coating is 13.9 nm, which is much larger than that of FCSC (6.8 nm), indicating that silica in the composite effectively prevents the Co 3 O 4 crystals from getting larger during calcination …”

Wear behavior of Ag implantation GH4169 alloy by ion beam assisted bombardment

“…The detection range is below 2–10 nm from the surface for XPS, while it is above 100 nm for EDS. 26 Namely, there a very thin Ag layer may be deposited on the GH4169 alloy after Ag implantation.

Figure 3.The Ag3d XPS spectra of the S1 (a) and S4 (b) before the wear test with the increasing of XPS Ar + sputtering time.

Figure 4.The atomic fraction of Ag, Fe, and Ni of the S4 with the increasing of Ar + sputtering time.

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“…The detection range is below 2-10 nm from the surface for XPS, while it is above 100 nm for EDS. 26 Namely, there a very thin Ag layer may be deposited on the GH4169 alloy after Ag implantation. Figure 5(a) shows friction coefficient evolution of the samples with the sliding time (N1, S1, S4) under a normal load of 1 N. Compared with the bare GH4169 alloy (N1), the friction coefficient of S1 has almost not changed in the whole test time.…”

Optimized permeation and antifouling of PVDF hybrid ultrafiltration membranes: synergistic effect of dispersion and migration for fluorinated graphene oxide

“…XPS and EDS had different capabilities, limitations, and depths of analysis, and these techniques might provide differing results from each other (Gorzalski et al 2017;Xu et al 2016). In order to understand the migration behavior of FGO, we attempted to use XPS, EDS, and indirect computation to detect oxygen contents in different depths of membranes and then analyzed FGO contents in the top layer, sublayer, and the whole membrane, respectively.…”