Magnetic porous Ag2O/Chitin nanostructure adsorbent for eco-friendly effective disposing azo dyes

Progress in photocatalytic degradation of industrial organic dye by utilising the silver doped titanium dioxide nanocomposite

Industrial organic dyes represent a significant portion of pollutants discharged into the environment, particularly by the textile industry. These compounds pose serious threats to living organisms due to their high toxicity. Various techniques have been explored for the degradation of organic dyes, among which heterogeneous photocatalysis utilising titanium dioxide (TiO2) stands out as a promising technology. However, the practical application of TiO2 as photocatalyst has limitations for the following reasons; First, TiO2 has a low sensitivity to visible light due to a large band gap which can be 3.2 eV for the anatase polymorph. Second, the recombination rate of photo-induced electron-hole pairs in TiO2 is very fast. Recent research studies have brought to light that a silver-doped titanium dioxide nanocomposite could be one of the promising answers to these problems. This nanocomposite has garnered significant attention because of its unique features that suggest the manifestation of more effective concepts to minimize the electron-hole recombination and broaden light absorption. This causes Schottky barrier which is essentially created by integrating the silver nanoparticles into titanium dioxide. It is quite significant in decelerating the recombination of the electron-hole pairs, thus increasing photocatalytic activity. Further, it is more effective in that the use of silver also widens the titanium dioxide absorption range to the visible light hence maximizing capture and conversion of broader range of light energies for catalytic reactions. This paper therefore seeks to examine the research background regarding the industrial organic dyes starting with the history of industrial organic dyes before delving into an evaluation of the current and most current research on industrial organic dyes looking at advanced methods of their degradation with specific focus on silver-doped TiO2 for photocatalytic enhancement. This paper also reviews the experimental work concerning the actual photocatalytic degradation process and presents the factors affecting the performance of silver-doped TiO2 nanocomposites by eliminating organic dyes from wastewater. It also encompasses a general background into the various synthesis methods used in the preparation of silver-doped TiO2 nanocomposites. Additionally, challenges and future perspectives in the field are outlined, with a focus on the development of novel strategies to further improve the efficiency and sustainability of silver-doped TiO2 photocatalysts for industrial organic dye degradation. In conclusion, this review offers a significant outlook on the existing literature concerning the silver-doped TiO2 nanocomposites for effective photocatalytic degradation of the industrial organic dyes because of the rising pollution level and helping future researchers in seeking the solutions for environmental issues and developing sustainable wastewater treatment.

Surface engineering of multifunctional nanostructured adsorbents for enhanced wastewater treatment: A review

Rapid urbanization and industrialization have significantly contributed to the contamination of the environment through the discharge of wastewater containing various pollutants. The development of high-performance surface functional nanostructured adsorbents is of wide interest for researchers. Therefore, we explore the significant advancements in this field, focusing on the efficiency of nanostructured materials, as well as their nanocomposites, for wastewater treatment applications. The crucial role of surface modification in enhancing the affinity of these nanostructured adsorbents towards targeted pollutants, addressing a key bottleneck in the utilization of nanomaterials for wastewater treatment, was specifically emphasized. In addition to highlighting the advantages of surface engineering in enhancing the efficiency of nanostructured adsorbents, this review also provides a comprehensive overview of the limitations and challenges associated with surface-modified nanostructured adsorbents, including high cost, low stability, poor scalability, and potential nanotoxicity. Addressing these limitations is essential for realizing the commercial viability of these state-of-the-art materials for large-scale wastewater treatment applications. This review also thoroughly discusses the potential scalability and environmental safety aspects of surface-modified nanostructured adsorbents, offering insights into their future prospects for wastewater treatment. It is believed that this review will contribute significantly to the existing body of knowledge in the field and provide valuable information for researchers and practitioners working in the area of environmental remediation and nanomaterials.

Methylene blue removal using modified poly(glycidyl methacrylate) as a low-cost sorbent in batch mode: kinetic and equilibrium studies

Industrial textile wastewater contains large amounts of cationic dye material. Therefore, a new adsorbent was synthesized as modified poly(glycidyl methacrylate) (mPGMA) with a fluorine group-containing compound 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP). mPGMA was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectrometer (FTIR). The proposed adsorbent has been used to remove methylene blue (MB) from aqueous solutions by the adsorption process. In further experiments, the removal efficiency of adsorbent in both powder (˂600 μm) and granular form was compared from aqueous solutions by adsorption process. Furthermore, the effects of changing parameters such as adsorbent dosage, contact time, pH, temperature, and initial dye concentration on methylene blue adsorption were investigated. Also, Langmuir, Freundlich, and Temkin isotherms have been used to describe the equilibrium characteristics of adsorption. Finally, the experimental data fitted well by Langmuir isotherm with a maximum adsorption capacity of 17.5 mg g-1. The experimental data were applied to pseudo-first- and second-order models. The experimental results were better fitted for the pseudo-second-order model than the other model. Consequently, the experimental results showed that mPGMA is a suitable low-cost adsorbent with great potential benefit in removing methylene blue from aqueous solutions.

Fabrication of EVOH/PANI Composite Nanofibrous Aerogels for the Removal of Dyes and Heavy Metal Ions

Water pollution caused by the leakage and discharge of pollutants, such as dyes and heavy metal ions, can cause serious damage to the environment and human health. Therefore, it is important to design and develop adsorbent materials that are efficient and multifunctional for the removal of these pollutants. In this work, poly(vinyl alcohol-co-ethylene) (EVOH)/polyaniline (PANI) composite nanofibrous aerogels (NFAs) were fabricated via solution oxidation and blending. The aerogels were characterized by a scanning electron microscope, Fourier transform infrared spectrometry, a contact angle measuring instrument and a universal testing machine. The influences of the introduction of PANI nanorods on the structural properties of aerogels were investigated, and the adsorption performance of aerogels was also studied. The results showed that the introduction of PANI nanorods filled the fibrous network structure, reduced porosity, increased surface hydrophilicity and improved compressive strength. Furthermore, EVOH/PANI composite NFAs possess good adsorption performances for dyes and heavy metal ions: The adsorption capacities of methyl orange and chromium ions (VI) are 73.22 mg/g and 115.54 mg/g, respectively. Overall, the research suggests that EVOH/PANI NFAs have great potential as efficient and multifunctional adsorbent materials for the removal of pollutants from water.