Copper nanoclusters-doped novel carrier with synergistic adsorption-catalytic active sites to enable high-performance dye removal.

Enhancing the synergistic interplay between adsorption and catalytic oxidation to amplify Fenton-like effects remains a pivotal challenge in advancing water pollution remediation strategies. In this study, a suite of novel carriers (SH) composed of silica (SiO2) and hydroxyapatite (HAp) in different ratios were synthesized through an amalgamation of the sol-gel and co-precipitation techniques. Notably, various forms of copper (Cu) species, including Cu2+ ions and Cu nanoclusters (Cu NCs), could be stably incorporated onto the SH surface via meticulous loading and doping techniques. This approach has engendered a new class of Fenton-like catalysts (Cu NCs-SH1-5) characterized by robust acid-base tolerance stability and remarkable recyclability. Compared with the previously reported Cu NCs-HAp, this catalyst with lower Cu species content could achieve better performance in adsorbing and degrading dyes under the aid of hydrogen peroxide (H2O2). The catalyst's dual action sites, specifically the adsorption sites (SiOH, POH, slit pores) and catalytic centers (multivalent Cu species), had clear division of labor and collaborate with each other. Further, reactive oxygen species (ROS) identification and astute electrochemical testing have unveiled the mechanism underpinning the cooperative degradation of dyes by three types of ROS, spawned through electron transfer between the Fenton-like catalyst (Cu NCs-SH) and H2O2. From these insights, the mechanism of synergistic adsorption-catalytic removal was proposed.

Enhancing Fenton-like Degradation of Organic Pollutants at Neutral pH by Multivalent Cu NCs/HAp Nanocatalysts.

Heterogeneous Fenton-like catalysis is a widely used method for the degradation of organic pollutants. However, it still has some limitations such as low activity in the neutral condition, low conversion rates of metals with different valence states, and potential secondary metal pollution. In this study, a Fenton-like nanocatalyst was first created by generating ultrasmall copper nanoclusters (Cu NCs) on the surface of hydroxyapatite (HAp) through a process of doping followed by modification. This resulted in the formation of a composite nanocatalyst known as Cu NCs/HAp. With the help of hydrogen peroxide (H2O2), Cu NCs/HAp exhibits an outstanding Fenton-like catalytic performance by efficiently degrading organic dyes such as methylene blue under mild neutral conditions. The removal rate can reach over 83% within just 30 min, demonstrating ideal catalytic universality and stability. The improved Fenton-like catalytic performance of Cu NCs/HAp can be ascribed to the synergistic effect of the multivalent Cu species through two simultaneous reaction pathways. During route I, the embedded Cu NCs with a core-shell Cu0/Cu+ structure can undergo sequential oxidation to form Cu2+, which continuously activates H2O2 to generate hydroxyl radicals (•OH) and singlet oxygen (1O2). In route II, Cu2+ produced from route I and initially adsorbed on the surface of HAp can be reduced by H2O2, thus regenerating Cu+ species for route I and achieving a closed-loop reaction. This work has confirmed that Cu NCs loaded on HAp may be an alternative Fenton-like catalyst for degradation of organic pollutants and environmental remediation, opening up new avenues for potential applications of other Cu NCs in future water pollution control.

Controlled synthesis of CdSe and CdSe/CdS core/shell nanoparticles using Gemini surfactant Py-16-10-16 and their bioconjugates with BSA.

CdSe and CdSe/CdS core/shell nanoparticles (NPs) were synthesized by using Gemini surfactant, 1,10-bis(alpha-hexadecyl pyridine) decamethylene dibromide (abbreviated Py-16-10-16), as a soft template. Subsequent analysis revealed that the as-synthesized CdSe NPs and CdSe/CdS core/shell NPs were highly luminescent with quantum yields of 18% and 35%, respectively, compared with Rhodamine 6G (95%). Furthermore, when the nanoparticles were conjugated with bovine serum albumin (BSA) in PBS buffer solution (pH 7.40), the fluorescence intensity of the BSA system was quenched by the addition of CdSe/TGA or CdSe/CdS/TGA NPs, while the fluorescence intensities of CdSe/TGA and CdSe/CdS/TGA NPs were enhanced by the addition of BSA. This enhancement and quenching of the fluorescence intensity by conjugating with BSA could be used to determine the albumin concentration.