Sulfonated magnetic multi-walled carbon nanotubes with enhanced bonding stability, high adsorption performance, and reusability for water remediation

Simplex-lattice design and decision tree optimization of endophytic Trichoderma-multi-walled carbon nanotube composite for enhanced methylene blue removal

This study investigates a novel approach for enhancing methylene blue (MB) removal from water using a composite of endophytic Trichoderma mate and multi-walled carbon nanotubes (MWCNTs). For the first time, a unique combination of simplex-lattice design and decision tree learning algorithm was employed to optimize MB removal. This innovative approach effectively identified the optimal composite ratio of hyphal mate (0.5354 g/L) and MWCNTs (0.4646 g/L) for maximizing MB removal, which achieved remarkable removal efficiency ranging from 63.50 to 95.78 % depending on the combination used. The DT model further demonstrated promising potential for predicting MB removal efficiency. SEM revealed a unique hybrid material formed by the intertwining or entrapment of MWCNTs within the hyphal network of Trichoderma mate. FT-IR analysis confirmed the presence of novel functional groups on the MWCNTs' surface at 2438.79 and 528.25 cm-1, likely due to interactions with the endophytic fungi's biomolecules. These functional groups presumably act as reducing and stabilizing agents, promoting efficient MB adsorption. This research paves the way for utilizing the combined biological and chemical approach (fungal biomass and MWCNTs) in bioremediation applications. The findings suggest significant potential for practical applications in wastewater treatment, providing an eco-friendly and cost-effective method for dye removal. Furthermore, the proposed method shows promise for scaling up to industrial wastewater treatment and applicability in resource-limited settings, offering a sustainable solution for global water pollution challenges. Further investigations with larger datasets incorporating additional influencing factors are necessary to refine the predictive power of the DT model for practical applications.

Locally Synthesized Zwitterionic Surfactants as EOR Chemicals in Sandstone and Carbonate

Zwitterionic surfactants are found to be highly effective in reducing the IFT and changing the wettability. This work studied the solubility and wettability alteration performance of locally synthesized zwitterionic surfactants in Berea sandstone and Indiana limestone. Contact angle measurements were conducted to study the wettability under different conditions. SEM images and TGA results were combined to reflect on the wettability alteration mechanism. The zeta potential test was adopted to study the surface charge of the Indian limestone powder. Results showed that five of the six surfactants dissolved in deionized water to form 1.0 wt % solution, indicating efficient solubility for EOR purposes. Although its wettability alteration performance on oil-aged Berea sandstone is weak to moderate, the performance of ZW6 on Indiana limestone is excellent. ZW6 can change the strongly oil-wet (162°) rock back to water-wet (62.9°) conditions. Increasing its concentration from 0.01 to 0.5 wt % continuously enhanced the performance. The addition of NaCl to 150000 ppm did not affect the wettability alteration. However, the addition of CaCl2 largely suppressed the wettability alteration, while Na2SO4 and MgCl2 both enhanced the performance. With the same headgroup, a more hydrophobic tail group impairs the wettability alteration. The quite different wettability alteration performance of MgCl2 and CaCl2 cases (which had approximately the same amount of calcite dissolution), and the comparable wettability alteration performance of Na2SO4 and MgCl2 (which had very different calcite dissolution amounts) indicate that calcite dissolution is unrelated to wettability alteration.

Polydopamine-modification of a magnetic composite constructed from citric acid-cross-linked cyclodextrin and graphene oxide for dye removal from waters

The effect of polydopamine (PDA) modification on aminated Fe₃O₄ nanoparticles (Fe₃O₄-NH₂)/graphite oxide (GO)/β-cyclodextrin polymer cross-linked by citric acid (CDP-CA) composites were studied for the removal of a cationic dye (methylene blue, MB) and an anionic dye (Congo red, CR) from waters. The micro-structural and magnetic characterizations confirmed the successful preparation of Fe₃O₄-NH₂/GO/CDP-CA and PDA/Fe₃O₄-NH₂/GO/CDP-CA composites. The maximum MB and CR adsorption capacities of Fe₃O₄-NH₂/GO/CDP-CA were 75 mg/g and 104 mg/g, respectively, while the corresponding amounts for PDA/Fe₃O4-NH₂/GO/CDP-CA composite were 195 mg/g and 64 mg/g, respectively. The dye sorption behaviors of these two composites were explained by their corresponding surface-charged properties according to the measured zeta potential results. Moreover, the high saturation magnetizations and the stable dye removal rate in the adsorption-desorption cycles indicated the good recyclability and reusability of the fabricated composites.

Carbon Nanotube-Supported Dummy Template Molecularly Imprinted Polymers for Selective Adsorption of Amide Herbicides in Aquatic Products

In this study, a carbon nanotube (CNTs)-supported dummy template molecularly imprinted polymer (DMIPs) material was synthesized and utilized for the detection of amide herbicides in aquatic products via matrix solid-phase dispersion technology (MSPD). The DMIPs material was characterized, and its adsorption kinetics and isotherm were determined, the adsorption model was established, and the selective adsorption coefficient was calculated. The extract parameters of the method were optimized and successfully employed for the separation, analysis and detection of real samples, with satisfactory detection limits and linear ranges obtained. By comparing with other methods, the CNTs@DMIPs combined with MSPD technology established in our study can effectively solve false negative problems caused by insufficient destructive force, using dummy template molecules can also address the issue of false positives caused by template molecule leakage in molecular imprinting. Overall, the method is appropriate for the separation and detection of endogenous substances from highly viscous and poorly dispersed samples and is used as a routine detection tool in the aquaculture industry.