Statistically Optimum HKUST-1 Synthesized by Room Temperature Coordination Modulation Method for the Adsorption of Crystal Violet Dye

PEGylation of a shell over core-shell MOFs-a novel strategy for preventing agglomeration and synergism in terms of physicochemical and biological properties

We demonstrate a new strategy of PEGylation over core-shell MOFs of HKUST-1 and Cu-MOF-2 by a solvothermal method. The novel synthesized PEGylated core-shell MOFs has synergistic enhancement in terms of physicochemical and biological properties. FTIR spectroscopy and XRD analysis described the bonding characteristics of the double-shelled-core MOFs PEG@HKUST-1@CuMOF-2 and PEG@CuMOF-2@HKUST-1. XPS and EDAX spectroscopy confirmed the structural features of the PEG@core-shell MOFs. The as-synthesized PEG-modified core-shell MOFs showed a readily identifiable morphology with a reduction in particle size. The significant observation from SEM and TEM was that agglomeration disappeared completely, and the morphology of individual core-shell MOFs was clearly revealed. BET analysis provided the surface characteristics of MOF compounds. The chemical states of frameworks were established by XPS. The designed PEG-modified copper MOFs were evaluated for their activity against Gram-positive (Staphylococcus aureus, Enterococcus faecalis), Gram-negative (Escherichia coli and Klebsiella pneumoniae) bacterial species and activity against fungal species (Aspergillus niger and Candida albicans). This research work highlights a facile and synergistic approach to design promising biocompatible nano-dimensional core-shell MOFs for biological applications.

Cellulose acetate/MOF film-based colorimetric ammonia sensor for non-destructive remote monitoring of meat product spoilage

Herein, we designed an on-site and portable colorimetric assay using cellulose acetate polymeric films incorporated with HKUST-1 metal-organic framework while immersed in a solution of methyl red and brilliant cresyl blue organic dyes as an indicator for monitoring ammonia levels. Ammonia serves as a significant biomarker of food spoilage which falls under the category of volatile organic compounds (VOCs). The designed colorimetric solid-state sensor was comprehensively characterized using FE-SEM, EDS-mapping, XRD, FTIR, and contact angle analyses. The results confirmed the superior stability, water permeability, good crystallinity and desirable morphology of the prepared sensor platform. Additionally, customized smartphone was developed and applied for online signaling and colorimetric analysis. The findings demonstrated two linear ranges: 1-100 ppb and 0.1-1340 ppm with a detection limit of 0.02 ppm. The solid-state sensor exhibited high selectivity in the presence of other VOCs such as methanol, ethanol, acetone, 2-propanol, toluene, humidity, and hexane. It displayed acceptable repeatability in both inter-day (RSD = 3.38 %) and intraday (RSD = 3.86 %), long-term stability over 4 days as well as reusability over 3 cycles. We successfully applied this sensing platform for ammonia monitoring in spoiled meat foods including veal, fish and chicken. The results indicated favorable percentage recovery and repeatability, confirming the feasibility and potential applicability of this intelligent packaging system for monitoring freshness. The platform allows for real-time monitoring and data analysis via smartphone-based online signaling, providing a convenient and effective method for ensuring food quality.

Comprehensive evaluation of HKUST-1 as an efficient adsorbent for textile dyes

This study aimed to comprehensively assess the performance of HKUST-1, a metal-organic framework (MOF), as an adsorbent for various classes of textile dyes, including direct, acid, basic, and vinyl sulfonic reactive dyes. Real-world dyeing scenarios were simulated using carefully selected combinations of dyes to evaluate HKUST-1's effectiveness in treating dyeing process effluents. The results demonstrated that HKUST-1 exhibited highly efficient adsorption capabilities across all dye classes. Isolated direct dyes showed the best adsorption outcomes, with adsorption percentages exceeding 75% and reaching 100% for direct blue dye (Sirius Blue K-CFN). Basic dyes exhibited adsorption levels of nearly 85% for blue dye (Astrazon Blue FG), while the adsorption performance for the yellow dye (Yellow GL-E) was the poorest. The adsorption of dyes in combined systems followed a similar trend to that of isolated dyes, with the trichromy of direct dyes yielding the best results. Kinetic studies indicated that the adsorption of dyes followed a pseudo-second-order model, with nearly instantaneous adsorption observed in all cases. Furthermore, most dyes adhered to the Langmuir isotherm, further confirming the effectiveness of the adsorption process. The exothermic nature of the adsorption process was evident. Importantly, the study demonstrated the feasibility of reusing the HKUST-1, highlighting its potential as an exceptional adsorbent for removing hazardous textile dyes from effluents.

Synthesis of Cellulose Nanocrystals/HKUST-1 Composites and Their Applications: Crystal Violet Removal and Doxorubicin Loading

This study developed a novel composite material containing cellulose nanocrystals (CNCs) and HKUST-1. Here, the addition of CNCs was used to enhance the characteristics of HKUST-1 in terms of surface area, adsorption ability, and functional groups. Here, the fabrication of CNCs@HKUST-1 composites was carried out by adding CNCs into the fabrication process of HKUST-1. The addition of CNCs provides additional functional groups on the surface of composite material which can be used to attach other organic compounds, such as in waste management and drug delivery systems. Here, CNCs@HKUST-1 composites were tested as a material for crystal violet (CV) removal and doxorubicin (DOX) loading. The removal capacity of CNCs@HKUST-1 composite towards CV molecules reached 1182.25 ± 27.74 mg/g, while the loading capacity for DOX drugs was around 1514.94 ± 11.67 mg/g. Both applications showed that CNCs@HKUST-1 composite had higher adsorption capacity and ability compared to its precursor materials, i.e., CNCs and HKUST-1.