Study on Magnetic Porous Carbon Microspheres as a Novel Adsorbent for Malachite Green

Abstract

In this paper, a novel adsorbent of magnetic mesoporous carbon microspheres (MCS) are prepared by template methods and using nano-Fe 3 O 4 particles as magnetic cores, and the adsorption capacity and mechanism are studied in detail. The results show that MCS exhibits high performance for removing malachite green (MG), the highest adsorption capacity can reach about 468.5 mg g À 1 . Furthermore, the Langmuir adsorption isotherm model and the quasi-second-order kinetic model can explain the experimental phenomena very well. And the high adsorption capacity of MCS is mainly attributed to its unique mesoporous structure by increasing the specific surface area and providing sufficient active sites. In addition, after magnetic separation and recovery, MCS can be regenerated with ethanol. And MCS maintains a high adsorption rate of 84.5 % after 5 cycles of MG adsorption and desorption. This composite material with high adsorption efficiency and rapid magnetic separation is a promising recyclable adsorbent for the actual wastewater treatment and purification process.

Synthesis and adsorption performance of fly ash/steel slag‐based geopolymer for removal of Cu (II) and methylene blue

“…Besides, as shown in Figure 10C,D, and Table 5, the enthalpy change (Δ H ) during the adsorption of MB and Cu 2+ by the G20 adsorbent was greater than 0, indicating that the two adsorption processes were a process of an endothermic reaction, and increasing the temperature was favorable for the adsorption 41,42 . It was generally considered that the value of Δ H between 0 and 20 kJ/mol was physical adsorption, and between 80 and 400 kJ/mol was chemisorption 43,44 . The ∆ H of the two adsorption processes were 52.348 and 34.987 kJ/mol, respectively, showing that the adsorption processes contained both physical and chemical adsorption.…”

“…41,42 It was generally considered that the value of ΔH between 0 and 20 kJ/mol was physical adsorption, and between 80 and 400 kJ/mol was chemisorption. 43,44 The ∆H of the two adsorption processes were 52.348 and 34.987 kJ/mol, respectively, showing that the adsorption processes contained both physical and chemical adsorption. Moreover, the Gibbs free energy change (∆G) of MB and Cu 2+ was calculated at -3.615~-9.345 kJ/mol and -0.759~-4.419 kJ/mol, respectively, which were all less than zero, indicating that the adsorption process of MB and Cu 2+ by the G20 adsorbent proceeded spontaneously.…”

Au-NP-Decorated Cotton Swabs as a Facile SERS Substrate for Food-Safety-Related Molecule Detection

“…The cotton swab substrate displayed the lowest SERS signal intensity in the absence of NaCl in the growth medium. The intensity of the characteristic peak at 1092 cm –1 increased as the NaCl concentration increased from 0 to 1.6 M. The increase in peak intensity is attributed to the aggregation of Au NPs in the presence of NaCl, resulting in the formation of closely spaced gold nanoarrays on the surface of the fibers. Meanwhile, the attractive effect of NaCl on Au NPs enhanced the adhesion of Au NPs to the swab, thus improving the modification of Au NPs and generating more hot spots.…”

“…The CS-Au NPs substrate exhibits high sensitivity and uniformity in the detection of 4MPY, indicating that coated cotton fabrics have excellent potential for application in SERS detection on complex surfaces. To further evaluate the broad applicability of the fabricated substrate, MG, a widely and frequently used insecticide in agriculture, 27 was selected as the sample pesticide residue for rapid detection on a fruit surface using the wipe sampling method based on the abovementioned characteristics of CS-Au NPs. Hence, the surfaces of fruits and vegetables such as apples, grapes, bottle gourds, and bitter gourds were spiked with MG residues (10 −2 M/cm −2 ) and detected using the Au NPs-CS substrate (Figure 6a).…”