RESUMEN
The current study involves a synthesis of a composite of nickel oxide nanoparticles (NiONPs) with a chromium dopant to yield (Cr/NiONPs). Synthesis of nickel oxide was performed by the co-precipitation method. The synthesis of the composite was conducted by the impregnation method. FTIR, EDX, SEM, and XRD were used to characterize the synthesized materials. The synthesised materials' point zero charges (PZC) were performed using the potentiometric titration method. The obtained results show that the PZC for neat nickel oxide was around 5, and it was around 8 for Cr/NiONPs. The adsorption action of the prepared materials was examined by applying them to remove Reactive Red 2 (RR2) and Crystal Violate (CV) dyes from solutions. The outcomes demonstrated that Cr/NiONPs were stronger in the removal of dyes than NiONPs. Cr/NiONPs achieved 99.9% removal of dyes after 1 h. Adsorption isotherms involving Freundlich and Langmuir adsorption isotherms were also conducted, and the outcomes indicated that the most accurate representation of the adsorption data was offered by Langmuir adsorption isotherms. Additionally, it was discovered that the adsorption characteristics of the NiONPs and Cr/NiONPs correspond well with the pseudo-second-order kinetic model. Each of the NiONPs and Cr/NiONPs was reused five times, and the results display that the effectiveness of the removal of RR2 dye slightly declined with the increase in reuse cycles; it lost only 5% of its original efficiency after the 5 cycles. Generally, Cr/NiONPs showed better reusability than NiONPs under the same conditions.
RESUMEN
The elimination of pollutants such as dyes and fungi has become a tedious process hence there is a need for multifunctional materials that can be used for the removal or degradation of various pollutants from wastewater. Here, a nickel oxide nanoparticle (NiONPs) was synthesized by the co-precipitation method. In the current study, a composite of nickel oxide nanoparticles (NiONPs) was synthesized using nitrogen and chromium as dopants to create (N/NiONPs) and (Cr/N/NiONPs), respectively and used for the removal of dyes and fungi. The synthesized nanocomposites were characterized using zeta potential (ZP), scanning electron microscopy (SEM), X-rays diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The NiONPs, N/NiONPs and Cr/N/NiONPs were tested for the degradation of two dye pollutants, Reactive blue 13 (RB13) and eosin dye. The obtained results showed that Cr/N/NiONPs were more efficient than NiONPs and N/NiONPs for dye degradation by applying the same irradiation conditions. The Cr/N/NiONPs nanocomposites showed very good degradation efficiency of dye up to 94.2% for the RB13 and 90.8% for the eosin. We also examined the antifungal action of the NiONPs, N/NiONPs and Cr/N/NiONPs against Trichoderma fungus. The results showed that the Cr/N/NiONPs have an extremely strong antifungal impact on Trichoderma. This could be explained by the strong adhesion of Cr/N/NiONPs to the Trichoderma surface due to electrostatic attraction. This work has demonstrated that it is possible to create environmentally safe materials that can be used for the degradation of different dyes and the improvement of more effective antifungal treatments with lower active agent doses for fungus control with potential big economic benefits.
RESUMEN
A novel hydroxypropyl cellulose (gHPC) hydrogel with graded porosity has been fabricated, in which pore size, shape, and mechanical properties vary across the material. The graded porosity was achieved by cross-linking different parts of the hydrogel at temperatures below and above 42 °C, which was found to be the temperature of turbidity onset (lower critical solution temperature, LCST) for the HPC and divinylsulfone cross-linker mixture. Scanning electron microscopy imaging revealed a decreasing pore size along the cross-section of the HPC hydrogel from the top to the bottom layer. HPC hydrogels demonstrate graded mechanical properties whereby the top layer, Zone 1, cross-linked below LCST, can be compressed by about 50% before fracture, whereas the middle and bottom layers (Zone 2 and 3, respectively) cross-linked at 42 °C, can withstand 80% compression before failure. This work demonstrates a straightforward, yet novel, concept of exploiting a graded stimulus to incorporate a graded functionality into porous materials that can withstand mechanical stress and minor elastic deformations.
RESUMEN
Antimould agents are widely used in different applications, such as specialty paints, building materials, wood preservation and crop protection. However, many antimould agents can be toxic to the environment. This work aims to evaluate the application of copper oxide nanoparticles (CuONPs) surface modified with boronic acid (BA) terminal groups as antimould agents. We developed CuONPs grafted with (3-glycidyloxypropyl) trimethoxysilane (GLYMO), coupled with 4-hydroxyphenylboronic acid (4-HPBA), which provided a strong boost of their action as antimould agents. We studied the antimould action of the 4-HPBA-functionalized CuONPs against two mould species: Aspergillus niger (A. niger) and Penicillium chrysogenum (P. chrysogenum). The cis-diol groups of polysaccharides expressed on the mould cell walls can form reversible covalent bonds with the BA groups attached on the CuONPs surface. This allowed them to bind strongly to the mould surface, resulting in a very substantial boost of their antimould activity, which is not based on electrostatic adhesion, as in the case of bare CuONPs. The impact of these BA-surface functionalized nanoparticles was studied by measuring the growth of the mould colonies versus time. The BA-functionalized CuONPs showed significant antimould action, compared to the untreated mould sample at the same conditions and period of time. These results can be applied for the development of more efficient antimould treatments at a lower concentration of active agent with potentially substantial economic and environmental benefits.
