3‑Mercapto‑propanoic acid modified cellulose filter paper for quick removal of arsenate from drinking water

Shopping around: Comparing Cd(II) sorption performance of disparate functional groups-modified microcrystalline cellulose composites

The structure-function relationship of functionalized microcrystalline cellulose (MCC) composites as adsorbents remains unclear. Herein, the orange peel-derived MCC (i.e., OP-OH-H-25) was treated by different functional agents to prepare adsorbents for cadmium (Cd(II)) removal. Mercaptoacetic acid and orthophosphoric acid did not apparently impact MCC's surface site types and contents. Alternatively, they efficiently purified OP-OH-H-25 and generated OP-OH-SH and OP-OH-P samples with increased cellulose amounts. In contrast, the glycine modification produced OP-OH-NH2 with fewer sulfhydryl/carboxyl functional groups and more amide/amino sites. The pH-dependent Cd(II) removal trends by the MCC-related materials showed three successive stages with disparate sorption modes. The Cd(II) sorption kinetics processes on OP-OH-SH, OP-OH-P, and OP-OH-NH2 reached equilibrium after 0.25 h, faster than 0.5 h on OP-OH-H-25. The maximum Cd(II) sorption capacities of MCC-related adsorbents were OP-OH-P (151.81 mg/g) > OP-OH-SH (150.80 mg/g) > OP-OH-H-25 (124.90 mg/g) > > OP-OH-NH2 (55.23 mg/g). OP-OH-P exhibited the strongest Cd(II) sorption ability under the interference of mixed aquatic components. The intrinsic Cd(II) sorption mechanisms were identified as inner-sphere complexation and cation-π bond interaction. Overall, the select priority of modifying agents is orthophosphoric acid > mercaptoacetic acid > > glycine when preparing functionalized MCC adsorbents for purifying Cd(II)-polluted water systems.

Aqueous phase synthesis of ion-imprinted cryogel for paper-based colorimetric detection of As(V) with high selectivity

A novel hydrophilic As(V) ion-imprinted cryogel (IIC) was green prepared by cryogelation in aqueous environment which was coincident with the adsorption condition and can improve the specific recognition performance. The methacrylamido propyl trimethyl ammonium chloride (MPTAC) was selected as the functional monomer and the saturated adsorption capacity of the prepared IIC and NIC were 55.0 mg/g and 29.4 mg/g, and with high imprinting factor of 1.87. Additionally, the prepared IIC showed admirable reusability and high selectivity, and the recovery was in the range 81.2-97.9% with RSD range of 1.9-4.3%, which was similar to the value obtained by hydride generation atomic absorption spectrometry. IIC can be used as solid material for colorimetric detection at the ultraviolet wavelength of 858 nm without color interference of material matrix, in the range 5-200 μg/L (R² = 0.990) with a detection limit of 0.970 µg/L. Obviously, this synthetic strategy provides a simple, efficient, and green method for the preparation of water-compatible ion-imprinted polymers providing selective separation and detection of trace As(V) in real complex samples.

Application progress of immobilized biomembrane in the discovery of active compounds of natural products

Natural products (NPs) are an important source of bioactive compounds. Considering their complex matrix effects, the development of suitable methodologies for the fast identification and analysis of active substances from NPs played a significant role in controlling their quality and discovering new drugs. In recent years, the technology of immobilized biomembrane has attracted increasing attention, due to its peculiarities such as multi-target efficiency, accuracy and/or time-saving compared with traditional activity-guided separation and ligand fishing methods. This article first provides a systematic review of the latest advances in screening technologies based on biomembrane in the field of NPs. It includes detailed discussions of these technologies, including cell membrane chromatography, artificial membrane chromatography, cell membrane fishing, living cell fishing methods, and their applications in screening various active molecules from NPs. Their limitations and future development prospects were further discussed.

Transfer hydrogenation of nitroarenes using cellulose filter paper-supported Pd/C by filtration as well as sealed methods

A reductive filter paper for selective nitro reduction has been prepared by modification of a pristine cellulose filter paper by Pd/C nanoparticles, as a portable catalyst. The reaction was performed in two different set-ups including (i) filtration and (ii) sealed systems, in the presence of ammonium formate and ex situ generated hydrogen gas reducing agents, respectively. In the sealed system in the presence of H2 gas, the halogenated nitroarenes were completely reduced, while in the filtration system, different derivatives of the nitroarenes were selectively reduced to aryl amines. In both systems, the reduction of nitroarenes to aryl amines was performed with high efficiency and selectivity, comparable to a heterogeneous system. Reaction parameters were comprehensively designed using Design Expert software and then studied. The properties of the catalytic filter paper were studied in detail from the points of view of swellability, shrinkage, reusability, and stability against acidic, alkaline, and oxidative reagents.

Catalytic filtration: efficient C-C cross-coupling using Pd(II)-salen complex-embedded cellulose filter paper as a portable catalyst

A new platform has been developed for environmentally friendly C–C cross-coupling reactions via filtration of reactants through a portable Pd(II)-salen complex-embedded filter paper.

Thiomers of Chitosan and Cellulose: Effective Biosorbents for Detection, Removal and Recovery of Metal Ions from Aqueous Medium

Removal of toxic metal ions using adsorbents is a well-known strategy for water treatment. While chitosan and cellulose can adsorb weakly some types of metals, incorporating thiols as metal chelating agents can improve their sorption behaviors significantly. Presented in this review are the various chemical modification strategies applicable for thiolation of chitosan and cellulose in the forms of mercaptans, xanthates and dithiocarbamates. Moreover, much attention has been paid to the specific strategies for controlling the thiolation degree and characterization approaches for establishing the structure-property relationship. Also, the kinetics and isotherm models that elucidate the adsorption processes and mechanisms induced by the thiomers have been explained. These thiomers have found great potentials in the applications associated with metal removal, metal recovery and metal detection.

AgNPs Ornamented Modified Bacterial Cellulose Based Self-Healable L-B-L Assembly via a Schiff Base Reaction: A Potential Wound Healing Patch

A layer-by-layer (L-B-L) bacterial cellulose (BC)-based transdermal patch has been prepared via a Schiff base reaction. The L-B-L assembly consisting of covalently cross-linked ethylene diamine-modified carboxymethylated BC isolated from the Glucanoacetobacter xylinus (MTCC7795) bacterial strain and aldehyde-modified pectin formed via a Schiff base reaction. The presence of the imine bond assists the self-healing process after being scratched in the presence of a pH 7.4 buffer solution monitored via optical microscopy, atomic force microscopy, and tensile strength analyses. The formation of the L-B-L assembly was confirmed using field-emission scanning electron microscopy (FESEM) analysis. Simultaneously, water swelling and deswelling studies were carried out to test its water retention efficiency. The presence of silver nanoparticles (AgNPs) has been confirmed by ultraviolet-visible spectroscopy and FESEM analyses. The antimicrobial activity of the AgNPs-incorporated transdermal patch has been examined over Staphylococcus aureus and Escherichia coli using the zone of inhibition method. Additionally, the cell viability assay was performed using the fluorescent dyes 4',6-diamidino-2-phenylindole and propidium iodide. The AgNPs in the L-B-L assembly showed antimicrobial property against both types of bacteria. The cytotoxicity and wound healing property of the patch system have been studied over NIH 3T3 fibroblast and A549 epithelial cell lines. The L-B-L film also influenced the wound healing process of these two cell lines.

Arsenate removal from aqueous solutions by cuttlebone/copper oxide nanobiocomposite

This study aims to illustrate the preparation of a new nanobiocomposite by incorporating copper oxide nanoparticles into cuttlebone matrix (CB/CuO NPs), and it was tested to define how effective it was to adsorb and remove arsenate from aqueous systems. CB is the bone tissue of cuttlefish with high porosity, permeability, and low cost. CuO NPs have been introduced as an effective arsenate adsorbent. Producing nanocomposite by introducing of CuO NPs in the structure of CB enhanced their stability and facilitated their separation from solution. Incorporation of CuO NPs in the structure of CB enhanced the adsorption capacity of CB. The adsorption data were fitted with both Langmuir and Freundlich isotherms, but Langmuir isotherm exhibited better matching rather than Freundlich isotherm. The maximum adsorption capacity (q_max) was calculated from Langmuir adsorption isotherm which was around 25.13 mg g^-1. Kinetic data fitted well to the pseudo-second-order reaction model. The results indicate that the possible mechanism of arsenate adsorption on CB/CuO is through development of inner sphere complex. Simple preparation and abundant and good adsorption capacity in the presence of calcium ions indicate that the CB/CuO is suitable for removal of arsenate from contaminated drinking water.