In situ speciation analysis and kinetic study of arsenic adsorption on ferrihydrite with surface-enhanced Raman spectroscopy

Highly sensitive and selective SERS substrates with 3D hot spot buildings for rapid mercury ion detection

“…S2 †) and discovered that the 16 nm gold nanoparticles on the gold film assembly exhibit a block structure, which creates the electron tunneling effect and significantly reduces the strength of the local electromagnetic field. 37,38 Compared to the other three sizes of SERS substrates, the capillary assembled by 80 nm Au NPs produces relatively less hot spot density, which is primarily attributable to its lower assembly concentration. The capillary assembled by 45 nm gold particles has a higher assembly density, but its electromagnetic field strength may not be as strong as that produced by 55 nm particles.…”

Efficient arsenic coagulation by serpentine-mediated iron hydroxides

“…Similar peaks from As(V)-O-Fe stretching and As(III)-O-Fe vibrations were noted at 832 and 820 cm À1 in arsenic-ferrihydrite system. 36 Thus, we deduced that these two peaks should be assigned to As(V)-O-Mg and As(III)-O-Mg vibrations.…”

“…33 It is likely that inner-sphere complexes form between arsenic and iron hydroxides after coagulation. 36,38 The contribution of arsenic adsorption by magnesium in serpentine was studied with Mg 1s and O 1s spectra (Fig. 4b and c).…”

“…4d). 36 As an in situ monitoring strategy, the characteristic Raman response of arsenic was compared before and after mixing with serpentine. The vibrational peaks of serpentine at 1095 and 331 cm −1 were contributed from Si–O stretching and SiO 4 bending vibrations, respectively.…”

Application of surface-enhanced Raman scattering to qualitative and quantitative analysis of arsenic species

“…Arsenic levels in groundwater vary greatly depending on the source and geographic conditions; therefore, monitoring methods with a high sensitivity and a wide linear range are necessary to meet the needs of environmental monitoring. [65][66][67] In 1988, Greaves and Griffith rst reported SERS spectra of samples with high concentrations (>1 × 10 5 mg L −1 ) of As(V) using Ag as the SERS substrate. 43 The Raman spectra were measured aer increasing the concentration of an arsenic solution by a factor of 1000 and using the same laser excitation, and the intensity of the spectra was found to be linearly dependent on the arsenic concentration.…”