Functionalized Materials as a Versatile Platform for Enzyme Immobilization in Wastewater Treatment

Purpose of Review Untreated wastewater discharge can significantly and negatively impact the state of the environment. Rapid industrialization and economic development have directly contributed to land and water pollution resulting from the application of many chemicals such as organic dyes, pharmaceuticals, and industrial reagents. The removal of these chemicals before effluent discharge is crucial for environmental protection. This review aims to explore the importance of functionalized materials in the preparation of biocatalytic systems and consider their application in eliminating water pollutants. Recent Findings Wastewater treatment methods can be classified into three groups: (i) chemical (e.g., chemical oxidation and ozonation), (ii) physical (e.g., membrane separation and ion exchange), and (iii) biological processes. Biological treatment is the most widely used method due to its cost-effectiveness and eco-friendliness. In particular, the use of immobilized enzymes has recently become more attractive as a result of scientific progress in advanced material synthesis. The selection of an appropriate support plays an important role in the preparation of such biologically active systems. Recent studies have demonstrated the use of various materials for enzyme immobilization in the purification of water. Summary This review identifies and discusses different biocatalytic systems used in the enzymatic degradation of various water pollutants. Materials functionalized by specific groups can serve as good support matrices for enzyme immobilization, providing chemical and thermal stability to support catalytic reactions. Enzymatic biocatalysis converts the pollutants into simpler products, which are usually less toxic than their parents. Due to immobilization, the enzyme can be used over multiple cycles to reduce the cost of wastewater treatment. Future studies in this field should focus on developing new platforms for enzyme immobilization in order to improve degradation efficiency

Modified and unmodified zinc oxide as coagent in elastomer compounds

The aim of this work was to study the activity of unmodifi ed and modifi ed ZnO in the peroxide crosslinking of hydrogenated acrylonitrile-butadiene elastomer (HNBR) and ethylene-propylene copolymer (EPM). In the fi rst step, zinc oxide was obtained by emulsion precipitation. Maleic acid was introduced onto the surface of ZnO Rusing an in situ method. The unmodified and modified zinc oxide was characterized using dispersive and morphological analysis, BET surface area analysis, and elemental, spectroscopic and thermal analysis. In the second stage of the research, the ZnO/MA systems were incorporated into the structure of elastomer compounds improving the kinetic and mechanical properties of vulcanizates. The proposed modification method had a favorable effect on the physicochemical properties of the zinc oxide and on the kinetic and mechanical properties of the vulcanizates. This study demonstrated that modification of zinc oxide by maleic acid is a promising technique

Synthesis and characterization of hydroxyapatite/chitosan composites

Hydroxyapatite (HAp)/chitosan (CS) composites were synthesized via a one-step co-precipitation method from aqueous solution, with the use of calcium chloride (CaCl2) and disodium hydrogen phosphate (Na2HPO4). CS was obtained via partial deacetylation of chitin with the use of strong sodium hydroxide solution. Composites were prepared with various HAp/CS ratios (30/70, 50/50, 70/30, 85/15) for comprehensive comparison of their properties. Fourier Transform Infrared Spectroscopy (FT-IR) analysis showed that hydrogen bonds were formed between the organic matrix and the mineral compound, confirming a successful phase interconnection. X-ray diffraction patterns were obtained, enabling examination of the crystalline properties of the composites, including HAp identification. The porous structure parameters of the composites were investigated, and morphological analysis (SEM) was performed. Differential Thermal Gravimetry (DTG) analysis of the composites indicated that the material is thermally stable up to 200 oC. Additionally, Energy Dispersive Spectroscopy (EDS) analysis of the mineral was carried out to check the Ca/P ratio, and confirmed its similarity to pure HAp

Grown of highly porous ZnO-nanoparticles by pulsed laser ablation in liquid technique for sensing applications

Pulsed laser ablation technique in deionized water with low laser fluency has been explored to prepare uniform dispersed porous ZnO nanoparticles for sensing applications. Surface morphology, particle size, porous structure, roughness, elemental distribution, and chemical bonding of the synthesized ZnO are analyzed by TEM, FESEM, AFM, EDX, and FTIR spectroscopy, respectively. Sensing behavior is observed by UV–Vis absorption measurements. TEM and FESEM analysis show that the prepared ZnO-coated film has homogeneous, dispersed, highly porous, and crack-free surface; the average particle size are observed ~ 24.72 ± 2.97 nm. The porous structure is responsible for appropriate sensing behavior. Low roughness value ~ 1.52 nm which is analyzed by AFM is advantageous for sensing behavior. EDX spectrum and elements mapping clearly show the uniform Zn and O distribution. XRD analysis confirms the hexagonal wurtzite structure of ZnO. FTIR reveals the Zn and O chemical bonding successfully. UV-Visible analysis exhibits that the prepared ZnO matrix has good incorporation with multi-dyes solutions at pH values 10–12 with significant changes in color behavior. The highest pKa value ~ 9.77 at a wavelength of 598.28 nm was calculated for multi-dyes immobilized ZnO matrix. So, it can be concluded that prepared ZnO nanostructures are potential candidates for sensing application