Highly antifouling polymer-nanoparticle-nanoparticle/polymer hybrid membranes

Clay-reinforced PVC composites and nanocomposites

Clay-reinforced polyvinyl chloride (PVC) composites and nanocomposites are one of the newest and most important compounds studied and used in various applications, including the biomedical, automotive industry, water treatment, packaging, fire retarding, and construction. The most important clays used in the synthesis of these composites are Bentonite, Montmorillonite, Kaolinite, and Illite. The addition of these nanoclays to the PVC matrix improves mechanical properties, thermal stability, and yellowness index properties. In this chapter, a detailed study of PVC and its properties, types of nanoclays and their properties, modification of nanoclays, production methods of composites, and nanocomposites of PVC/clay, their characterization, and applications have been performed. Herein, the types, properties, and applications of PVC/clay nanocomposites, as well as their challenges and future remarks, are reviewed.

Polysaccharide nanocomposites in wastewater treatment: A review

In modern times, wastewater treatment is vital due to increased water contamination arising from pollutants such as nutrients, pathogens, heavy metals, and pharmaceutical residues. Polysaccharides (PSAs) are natural, renewable, and non-toxic biopolymers used in wastewater treatment in the field of gas separation, liquid filtration, adsorption processes, pervaporation, and proton exchange membranes. Since addition of nanoparticles to PSAs improves their sustainability and strength, nanocomposite PSAs has gained significant attention for wastewater treatment in the past decade. This review presents a comprehensive analysis of PSA-based nanocomposites used for efficient wastewater treatment, focusing on adsorption, photocatalysis, and membrane-based methods. It also discusses potential future applications, challenges, and opportunities in adsorption, filtration, and photocatalysis. Recently, PSAs have shown promise as adsorbents in biological-based systems, effectively removing heavy metals that could hinder microbial activity. Cellulose-mediated adsorbents have successfully removed various pollutants from wastewater, including heavy metals, dyes, oil, organic solvents, pesticides, and pharmaceutical residues. Thus, PSA nanocomposites would support biological processes in wastewater treatment plants. A major concern is the discharge of antibiotic wastes from pharmaceutical industries, posing significant environmental and health risks. PSA-mediated bio-adsorbents, like clay polymeric nanocomposite hydrogel beads, efficiently remove antibiotics from wastewater, ensuring water quality and ecosystem balance. The successful use of PSA-mediated bio-adsorbents in wastewater treatment depends on ongoing research to optimize their application and evaluate their potential environmental impacts. Implementing these eco-friendly adsorbents on a large scale holds great promise in significantly reducing water pollution, safeguarding ecosystems, and protecting human health.

Treating waste with waste: Adsorption of anionic dyes in wastewater with surfactant-modified phosphogypsum

Phosphogypsum (PG) is a solid waste generated during the wet process of phosphoric acid production. The environmental-friendly disposal and recycling of PG is vital in the field of environmental solid waste treatment. In this study, PG is used for adsorbent of dyes in wastewater to achieve the goal of recycling waste with waste. Surfactant-modified phosphogypsum (ODBAC@PG) was prepared using octadecyl dimethyl benzyl ammonium chloride (ODBAC) as modifier. ODBAC@PG exhibits high adsorption capability for anionic dyes (methyl blue (MeB) and indocyanine carmine (IC)). The pseudo-second-order kinetic model fits the kinetic experimental data for the adsorption of two organic anionic dyes. Langmuir adsorption isotherm fits the adsorption characteristics of MeB and IC on ODBAC@PG, exhibiting a monolayer adsorption pattern. Thermodynamic parameters indicate the spontaneous and exothermic properties of MeB and IC on ODBAC@PG. MeB and IC have antagonistic effects on each other in binary adsorption system. High adsorption capacity after six cycles of experiments demonstrates the high reusability of ODBAC@PG. The nature for the adsorption includes electrostatic interaction, hydrogen bond and hydrophobic interaction. Using ODBAC@PG for dyes wastewater treatment can accomplish the goal of treating waste with waste and turning waste into treasure.

Wastewater reuse in agriculture: Prospects and challenges

Sustainable water recycling and wastewater reuse are urgent nowadays considering water scarcity and increased water consumption through human activities. In 2015, United Nations Sustainable Development Goal 6 (UN SDG6) highlighted the necessity of recycling wastewater to guarantee water availability for individuals. Currently, wastewater irrigation (WWI) of crops and agricultural land appears essential. The present work overviews the quality of treated wastewater in terms of soil microbial activities, and discusses challenges and benefits of WWI in line with wastewater reuse in agriculture and aquaculture irrigation. Combined conventional-advanced wastewater treatment processes are specifically deliberated, considering the harmful impacts on human health arising from WWI originating from reuse of contaminated water (salts, organic pollutants, toxic metals, and microbial pathogens i.e., viruses and bacteria). The comprehensive literature survey revealed that, in addition to the increased levels of pathogen and microbial threats to human wellbeing, poorly-treated wastewater results in plant and soil contamination with toxic organic/inorganic chemicals, and microbial pathogens. The impact of long-term emerging pollutants like plastic nanoparticles should also be established in further studies, with the development of standardized analytical techniques for such hazardous chemicals. Likewise, the reliable, long-term and extensive judgment on heavy metals threat to human beings's health should be explored in future investigations.

Fe3O4@Gum Arabic modified polyvinyl chloride membranes to improve antifouling performance and separation efficiency of organic pollutants

Nanofiltration (NF) membranes are promising media for water and wastewater treatment; however, they suffer from their hydrophobic nature and low permeability. For this reason, the polyvinyl chloride (PVC) NF membrane was modified by iron (III) oxide@Gum Arabic (Fe₃O₄@GA) nanocomposite. First, Fe₃O₄@GA nanocomposite was synthesized by the co-precipitation approach and then its morphology, elemental composition, thermal stability, and functional groups were characterized by various analyses. Next, the prepared nanocomposite was added to the casting solution of the PVC membrane. The bare and modified membranes were fabricated by a nonsolvent-induced phase separation (NIPS) method. The characteristics of fabricated membranes were assessed by mechanical strength, water contact angle, pore size, and porosity measurements. The optimum Fe₃O₄@GA/PVC membrane had a 52 L m^-2. h^-1. bar^-1 water flux with a high flux recovery ratio (FRR) value (82%). Also, the filtration experiment exhibited that the Fe₃O₄@GA/PVC membrane could remarkably remove organic contaminants, achieving high rejection rates of 98% Reactive Red-195, 95% Reactive Blue-19, and 96% Rifampicin antibiotic by 0.25 wt% of Fe₃O₄@GA/PVC membrane. According to the results, adding Fe₃O₄@GA green nanocomposite to the membrane casting solution is a suitable and efficient procedure for modifying NF membranes.

ANFIS-based forming limit prediction of stainless steel 316 sheet metals

Effect of microstructure on the formability of the stainless sheet metals is a major concern for engineers in sheet industries. In the case of austenitic steels, existence of strain-induced martensite ([Formula: see text]-martensite) in their micro structure causes considerable hardening and formability reduction. In the present study, we aim to evaluate the formability of AISI 316 steels with different intensities of martensite via experimental and artificial intelligence methods. In the first step, AISI 316 grade steels with 2 mm initial thicknesses are annealed and cold rolled to various thicknesses. Subsequently, the relative area of strain-induced martensite are measured using metallography tests. Formability of the rolled sheets are determined using hemisphere punch test to obtain forming limit diagrams (FLDs). The data obtained from experiments were further utilized to train and validate an artificial neural fuzzy interfere system (ANFIS). After training the ANFIS, predicted major strains by the neural network are compared to a new set experimental results. The results indicate that cold rolling has unfavorable effects on the formability of this type of stainless steels while significantly strengthens the sheets. Moreover, the ANFIS exhibits satisfactory results in comparison to the experimental measurements.

Modification of reinforced hollow fiber membranes with WO3 nanosheets for treatment of textile wastewater by membrane bioreactor

In this study, performance of braid reinforced hollow fiber membrane containing polyvinylidene fluoride (PVDF) embedded with tungsten trioxide (WO₃) nanosheets in a membrane bioreactor (MBR) was examined for textile wastewater treatment. The WO₃ nanosheets was synthesized and blended at different concentrations (0.1-0.02 wt%) in casting solutions of the membranes. The WO₃ nanosheets characterized using various tests such as XRD, FTIR, SEM, EDS, dot-mapping, and TEM. Furthermore, the effects of the increased WO₃ nanosheets into the PVDF matrix on the membrane morphology, hydrophilicity, permeability, antifouling, and COD and color removal efficiency was investigated. The addition of 0.1 wt% of the nanosheets reduces the water contact angle from 69.3° to 62.5° while increasing overall porosity from 37.5 to 43.2%. COD and color removal for PVDF/0.10 wt% WO₃ membrane was between 86-89% and 72-76%, respectively. While the TMP of modified WO₃ membranes did not significantly increase due to antimicrobial properties of the WO₃ nanosheets, the TMP of the pure PVDF membrane increase, indicating considerable cake layer fouling. The results of this study showed that modification of PVDF braid reinforced hollow fiber membrane using WO₃ nanosheets is promising membrane for MBR systems.

Recent Advances on the Fabrication of Antifouling Phase-Inversion Membranes by Physical Blending Modification Method

Membrane technology is an essential tool for water treatment and biomedical applications. Despite their extensive use in these fields, polymeric-based membranes still face several challenges, including instability, low mechanical strength, and propensity to fouling. The latter point has attracted the attention of numerous teams worldwide developing antifouling materials for membranes and interfaces. A convenient method to prepare antifouling membranes is via physical blending (or simply blending), which is a one-step method that consists of mixing the main matrix polymer and the antifouling material prior to casting and film formation by a phase inversion process. This review focuses on the recent development (past 10 years) of antifouling membranes via this method and uses different phase-inversion processes including liquid-induced phase separation, vapor induced phase separation, and thermally induced phase separation. Antifouling materials used in these recent studies including polymers, metals, ceramics, and carbon-based and porous nanomaterials are also surveyed. Furthermore, the assessment of antifouling properties and performances are extensively summarized. Finally, we conclude this review with a list of technical and scientific challenges that still need to be overcome to improve the functional properties and widen the range of applications of antifouling membranes prepared by blending modification.

Silver and Gold Nanoparticles for Antimicrobial Purposes against Multi-Drug Resistance Bacteria

Several pieces of research have been done on transition metal nanoparticles and their nanocomplexes as research on their physical and chemical properties and their relationship to biological features are of great importance. Among all their biological properties, the antibacterial and antimicrobial are especially important due to their high use for human needs. In this article, we will discuss the different synthesis and modification methods of silver (Ag) and gold (Au) nanoparticles and their physicochemical properties. We will also review some state-of-art studies and find the best relationship between the nanoparticles’ physicochemical properties and potential antimicrobial activity. The possible antimicrobial mechanism of these types of nanoparticles will be discussed in-depth as well.