Polypyrole, polyaniline and sodium alginate biocomposites and adsorption-desorption efficiency for imidacloprid insecticide

Eco-friendly engineering of micro composite-based hydroxyapatite bio crystal and polyaniline for high removal of OG dye from wastewater: Adsorption mechanism and RSM@BBD optimization

The presence of harmful substances such as dyes in water systems poses a direct threat to the quality of people's lives and other organisms living in the ecosystem. Orange G (OG) is considered a hazardous dye. The existing paper attempts to evaluate a low-cost adsorbent for the effective removal of OG dye. The developed adsorbent Polyaniline@Hydroxyapatite extracted from Cilus Gilberti fish Scale (PANI@FHAP) was elaborated through the application of the in situ chemical polymerization method to incorporate PANI on the surface of naturally extracted hydroxyapatite FHAP. The good synthesis of PANI@FHAP was evaluated through multiple techniques including X-ray diffraction (XRD), Scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM/EDS), Fourier Transforms Infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) coupled with thermal differential analysis (DTA) analysis. The results reveal a highly ordered disposition of PANI chains on FHAP, resulting in a well-coated FHAP in the PANI matrix. Furthermore, the presence of functional groups on the surface of PANI such as amine (-NH2) and imine (=NH) groups would facilitate the removal of OG dye from contaminated water. The adsorption of OG onto PANI@FHAP was conducted in batch mode and optimized through response surface methodology coupled with box-Behnken design (RSM/BBD) to investigate the effect of time, adsorbent dose, and initial concentration. The outcomes proved that OG adsorption follows a quadratic model (R2 = 0.989). The kinetic study revealed that the adsorption of OG fits the pseudo-second-order model. On the other hand, the isotherm study declared that the Freundlich model is best suited to the description of OG adsorption. For thermodynamic study, the adsorption of OG is spontaneous in nature and exothermic. Furthermore, the regeneration-reusability study indicates that PANI@FHAP could be regenerated and reused up to five successive cycles. Based on the FTIR spectrum of PANI@FHAP after OG adsorption, the mechanism governing OG adsorption is predominantly driven by π-π interaction, electrostatic interaction, and hydrogen bonding interactions. The obtained results suppose that PANI@FHAP adsorbent can be a competitive material in large-scale applications.

Synthesis and Characterization of Environmentally Friendly β-Cyclodextrin Cross-Linked Cellulose/Poly(vinyl alcohol) Hydrogels for Adsorption of Malathion

The widespread use of malathion enhances agricultural plant productivity by eliminating pests, weeds, and diseases, but it may lead to serious environmental pollution and potential health risks for humans and animals. To mitigate these issues, environmentally friendly hydrogel adsorbents for malathion were synthesized using biodegradable polymers, specifically cellulose, β-cyclodextrin (β-CD), poly(vinyl alcohol) (PVA), and biobased epichlorohydrin as a cross-linker. This study investigated the effects of the cellulose-to-PVA ratio and epichlorohydrin (ECH) content on the properties and malathion adsorption capabilities of β-CD/cellulose/PVA hydrogels. It was found that the gel content of the hydrogels increased with a higher cellulose-to PVA and ECH ratio, whereas the swelling ratio decreased, indicating a denser structure that impedes water permeation. In addition, various parameters affecting the malathion adsorption capacity of the hydrogel, namely, contact time, pH, hydrogel dosage, initial concentration of malathion, and temperature, were studied. The hydrogel prepared with a β-CD/cellulose/PVA ratio of 20:40:40 and 9 mL of ECH exhibited the highest malathion adsorption rate and capacity, which indicated an equilibrium adsorption capacity of 656.41 mg g-1 at an initial malathion concentration of 1000 mg L-1. Fourier transform infrared spectroscopy (FTIR), ζ-potential, and X-ray photoelectron spectroscopy (XPS) and NMR spectroscopy confirmed malathion adsorption within the hydrogel. The adsorption process followed intraparticle diffusion kinetics and corresponded to Freundlich isotherms, indicating multilayer adsorption on heterogeneous substrates within the adsorbent, facilitated by diffusion.

Remediation technologies for neonicotinoids in contaminated environments: Current state and future prospects

Neonicotinoids (NEOs) are synthetic insecticides with broad-spectrum insecticidal activity and outstanding efficacy. However, their extensive use and persistence in the environment have resulted in the accumulation and biomagnification of NEOs, posing significant risks to non-target organisms and humans. This review provides a summary of research history, advancements, and highlighted topics in NEOs remediation technologies and mechanisms. Various remediation approaches have been developed, including physiochemical, microbial, and phytoremediation, with microbial and physicochemical remediation being the most extensively studied. Recent advances in physiochemical remediation have led to the development of innovative adsorbents, photocatalysts, and optimized treatment processes. High-efficiency degrading strains with well-characterized metabolic pathways have been successfully isolated and cultured for microbial remediation, while many plant species have shown great potential for phytoremediation. However, significant challenges and gaps remain in this field. Future research should prioritize isolating, domesticating or engineering high efficiency, broad-spectrum microbial strains for NEO degradation, as well as developing synergistic remediation techniques to enhance removal efficiency on multiple NEOs with varying concentrations in different environmental media. Furthermore, a shift from pipe-end treatment to pollution prevention strategies is needed, including the development of green and economically efficient alternatives such as biological insecticides. Integrated remediation technologies and case-specific strategies that can be applied to practical remediation projects need to be developed, along with clarifying NEO degradation mechanisms to improve remediation efficiency. The successful implementation of these strategies will help reduce the negative impact of NEOs on the environment and human health.

Low-cost materials as vehicles for pesticides in aquatic media: a review of the current status of different biosorbents employed, optimization by RSM approach

Water contamination by pesticides is increasing dramatically due to population growth and the extensive use of pesticides in agriculture, leading to grave environmental and health concerns. Thus, efficient processes and the design and development of effective treatment technologies are required due to the enormous demand for fresh water. The adsorption approach has been widely used to remove organic contaminants such as pesticides because of its performance, less expense, high selectivity, and simplicity of operation compared to other treatment technologies. Among alternative adsorbents, biomaterials abundantly available for pesticide sorption from water resources have attracted the attention of researchers worldwide. The main objective of this review article is to (i) present studies on a wide range of raw or chemically modified biomaterials potentially effective in removing pesticides from aqueous media; (ii) indicating the effectiveness of biosorbents as green and low-cost materials for removing pesticides from wastewater; and (iii) furthermore, report the application of response surface methodology (RSM) for modeling and optimizing adsorption.

Insights into the ubiquity, persistence and microbial intervention of imidacloprid

Imidacloprid, a neonicotinoid pesticide, is employed to increase crop productivity. Meanwhile, its indiscriminate application severely affects the non-target organisms and the environment. As an eco-friendly and economically workable option, the microbial intervention has garnered much attention. This review concisely outlines the toxicity, long-term environmental repercussions, degradation kinetics, biochemical pathways, and interplay of genes implicated in imidacloprid remediation. The studies have highlighted imidacloprid residue persistence in the environment for up to 3000 days. In view of high persistence, effective intervention is highly required. Bacteria-mediated degradation has been established as a viable approach with Bacillus spp. being among the most efficient at 30 ℃ and pH 7. Further, a comparative metagenomic investigation reveals dominant neonicotinoid degradation genes in agriculture compared to forest soils with distinctive microbial communities. Functional metabolism of carbohydrates, amino acids, fatty acids, and lipids demonstrated a significantly superior relative abundance in forest soil, implying its quality and fertility. The CPM, CYP4C71v2, CYP4C72, and CYP6AY3v2 genes that synthesize cyt p450 monooxygenase enzyme play a leading role in imidacloprid degradation. In the future, a systems biology approach incorporating integrated kinetics should be utilized to come up with innovative strategies for moderating the adverse effects of imidacloprid on the environment.

Characterization of New Polymer Material of Amino-β-Cyclodextrin and Sodium Alginate for Environmental Purposes

The β-cyclodextrin polymer (PβCD) cross-linked with pyromellitic dianhydride (PD) and functionalized with an amino group (PAβCD) was introduced into a matrix made of sodium alginate (SA). Scanning electron microscopy (SEM) images showed a homogeneous surface of the composite material. Infrared spectroscopy (FTIR) testing of the PAβCD confirmed polymer formation. The tested polymer increased its solubility relative to the polymer without the amino group. Thermogravimetric analysis (TGA) confirmed the stability of the system. Differential scanning calorimetry (DSC) showed the chemical binding of PAβCD and SA. Gel permeation chromatography (GPC-SEC) showed high cross-linking of PAβCD and allowed for accurate determination of its weight. The formation of the composite material such as PAβCD introduced into a matrix made of sodium alginate (SA) has several potential environmental implications, including the use of sustainable materials, reduced waste generation, reduced toxicity, and improved solubility.

An inclusive outlook on the fate and persistence of pesticides in the environment and integrated eco-technologies for their degradation

Intensive and inefficient exploitation of pesticides through modernized agricultural practices has caused severe pesticide contamination problems to the environment and become a crucial problem over a few decades. Due to their highly toxic and persistent properties, they affect and get accumulated in non-target organisms, including microbes, algae, invertebrates, plants as well as humans, and cause severe issues. Considering pesticide problems as a significant issue, researchers have investigated several approaches to rectify the pesticide contamination problems. Several analyses have provided an extensive discussion on pesticide degradation but using specific technology for specific pesticides. However, in the middle of this time, cleaner techniques are essential for reducing pesticide contamination problems safely and environmentally friendly. As per the research findings, no single research finding provides concrete discussion on cleaner tactics for the remediation of contaminated sites. Therefore, in this review paper, we have critically discussed cleaner options for dealing with pesticide contamination problems as well as their advantages and disadvantages have also been reviewed. As evident from the literature, microbial remediation, phytoremediation, composting, and photocatalytic degradation methods are efficient and sustainable and can be used for treatment at a large scale in engineered systems and in situ. However, more study on the bio-integrated system is required which may be more effective than existing technologies.

Rapid and efficient removal of multiple aqueous pesticides by one-step construction boric acid modified biochar

Tricyclazole, propiconazole, imidacloprid, and thiamethoxam are commonly used pesticides in paddy fields. It is necessary and practical to remove pesticides from the water environment because the low utilization rate of pesticides will produce residues in the water environment. It is known that there are few studies on the preparation of biochar adsorption pesticides by the walnut shell and few studies on the removal of tricyclazole and propiconazole. Based on this, this paper used the walnut shell as raw material and boric acid as an activator to prepare biochar by the one-step method. The boric acid modified walnut shell biochar (WAB4) with a specific surface area of 640.6 m² g^-1, exhibited the high adsorption capacity of all four pesticides (>70%) at pH 3-9. The adsorption capacities of tricyclazole, propiconazole, imidacloprid, and thiamethoxam were 171.67, 112.27, 156.40, and 137.46 mg g^-1, respectively. The adsorption kinetics fitted the pseudo-second-order kinetic model and the adsorption isotherm curves conformed to the Freundlich isotherm model. The adsorption of pesticides by WAB4 was associated with hydrogen bonding, pore filling, hydrophobic effects, and π-π interactions. More significantly, WAB4 has excellent adsorption capacity compared to other adsorbents for real water samples. Finally, walnut shell biochar has no significant acute toxicity to Daphnia magna. This work shows that walnut shell-based biochar has a good effect on the removal of pesticides at a wide range of pH and is economical and safe, providing a new idea for the removal of pesticides in water.

Iron-modified biochar derived from sugarcane bagasse for adequate removal of aqueous imidacloprid: sorption mechanism study

Adsorption has been considered as a promising remediation technology to separate organic and inorganic agrochemicals from contaminated soil and water. Low-cost adsorbents, including waste derived materials, clay composites, biochar, and biochar modified materials, have attracted enormous attention for the removal of organic contaminants, including pesticides. In this study, iron-modified base-activated biochar (FeBBC) was prepared by pyrolysis (at 400 °C for 1 h) of iron-doped base (KOH) activated sugarcane bagasse for the removal of a widely used insecticide, namely imidacloprid (IMI) from water. The maximum adsorption capacity of the adsorbent (FeBBC) was calculated as 10.33 (± 1.57) mg/g from Langmuir isotherm model. The adsorbents could remove up to ~ 92% of IMI from aqueous solution at 23.8 mg/L IMI. Experimental data fitted well with the Freundlich model and pseudo-second-order model, demonstrating physisorption, as well as chemosorption, contributed to the sorption process. Even at highly acidic/basic solution pH, the FeBBC could remove substantial amount of IMI demonstrating hydrophobic interaction and pore diffusion play vital role for removal of IMI. The slight improving of IMI sorption with increasing solution pH indicated the sorption was also facilitated through ionic interaction alongside physical sorption. However, physical sorption including hydrophobic interaction and pore-filling interaction plays a vital role in the sorption of IMI.

Imidacloprid degrading efficiency of Pseudomonas plecoglossicida MBSB-12 isolated from pesticide contaminated tea garden soil of Assam

Long-term use of toxic pesticides in agricultural grounds has led to adverse effects on the environment and human health. Microbe-mediated biodegradation of pollutants is considered an effective strategy for the removal of contaminants in agricultural and environmental sustainability. Imidacloprid, a neonicotinoid class of pesticides, was widely applied insecticide in the control of pests in agricultural fields including the tea gardens of Assam. Here, native bacteria from imidacloprid contaminating tea garden soils were isolated and screened for imidacloprid degradation efficiency under laboratory conditions. Out of the 30 bacterial isolates, 4 were found to tolerate high concentrations of imidacloprid (25,000 ppm), one of which isolate MBSB-12 showed the highest efficiency for imidacloprid tolerance and utilization as the sole carbon source. Morphological, biochemical, and 16 S ribosomal RNA gene sequencing-based characterization revealed the isolate as Pseudomonas plecoglossicida MBSB-12. The isolate reduced 87% of extractable imidacloprid from the treated soil in 90 days compared to the control soil (without bacterial treatment). High-Resolution Mass Spectrometry (HRMS) analysis indicated imidacloprid breakdown to comparatively less harmful products viz., imidacloprid guanidine olefin [m/z = 209.0510 (M + H)⁺], imidacloprid urea [m/z = 212.0502 (M + H)⁺] and a dechlorinated degraded product of imidacloprid with m/z value 175.0900 (M + H)⁺. Further investigation on the molecular machinery of P. plecoglossicida MBSB-12 involved in the degradation of imidacloprid is expected to provide a better understanding of the degradation pathway.

Synthesis of monolith silica anchored graphene oxide composite with enhanced adsorption capacities for carbofuran and imidacloprid

Highly efficient adsorbent was prepared for the removal of carbofuran and imidacloprid pesticides from wastewater. The silica monolith anchored graphene oxide composite was synthesized by the modified Fischer esterification protocol. The composite showed improved adsorption capacity for the removal of pesticides from wastewater. Graphene oxide was synthesized using the modified Hummer's method, while the silica monolith was prepared via sol-gel method. The composite was characterized via X-ray diffraction, Fourier transform infra-red, Brunauer Emmett and Teller (BET/BJH) analysis, zeta potential, and FESEM imaging. Different adsorption parameters such as pH, contact time, adsorbate and adsorbent concentration, and temperature were optimized for the adsorption of pesticides. The equilibrium and kinetic models were applied to the adsorption process of the pesticides. Qe of the composite as found to be 342.46 mg g^-1 for imidacloprid and 37.15 mg g^-1 for carbofuran. The adsorption process followed the pseudo 2nd order kinetic model for carbofuran (R²~0.9971) and imidacloprid (R²~0.9967). The Freundlich isotherm best fitted to the adsorption data of the pesticides with R² value of 0.9956 for carbofuran and 0.95 for imidacloprid. The resultant adsorbent/composite material came out with very good results for the removal of pesticides.

PbO2 modified BDD electrode by dicationic ionic liquids assisted electrodeposition for efficient electrocatalytic degradation of pesticide wastewater

Pesticide wastewater is difficult to treat, and it is necessary to develop a new anode material electrochemical oxidation to efficiently degrade pesticide wastewater. DIL-PbO₂-Ti/BDD electrodes with better electrocatalytic oxidation performance were obtained by using dicationic ionic liquid (DIL) for assisted electrodeposition of PbO₂ modified boron-doped diamond (BDD) electrodes. At a current density of 100 mA cm^-2 and a temperature of 25 °C, the DIL-PbO₂-Ti/BDD electrode was used as anode and titanium plate as cathode. The electrochemical window and oxygen evolution potential (OEP) of the DIL-PbO₂-Ti/BDD electrode obtained by CV testing at a scan rate of 50 mV s^-1 in 1 M H₂SO₄ were 4.12 and 3.29 V, respectively. Under the conditions of current density of 100 mA cm^-2, 25 °C, pH 12, salt content of 8%, chemical oxygen demand (COD) of 24,280.98 mg L^-1, and total nitrogen (TN) content of 5268 mg L^-1, after electrification for 12 h, the removal efficiency of COD and TN reached 64.88 and 67.77%, respectively, indicating that the DIL-PbO₂-Ti/BDD electrode has excellent electrocatalytic performance. In order to further understand the mechanism of electrochemical degradation of pesticide wastewater, HPLC-MS was used to detect the intermediates in the degradation process, and the possible degradation pathways were proposed in turn.

Recovery, regeneration and sustainable management of spent adsorbents from wastewater treatment streams: A review

Adsorption is the most widely adopted, effective, and reliable treatment process for the removal of inorganic and organic contaminants from wastewater. One of the major issues with the adsorption-treatment process for the removal of contaminants from wastewater streams is the recovery and sustainable management of spent adsorbents. This review focuses on the effectiveness of emerging adsorbents and how the spent adsorbents could be recovered, regenerated, and further managed through reuse or safe disposal. The critical analysis of both conventional and emerging adsorbents on organic and inorganic contaminants in wastewater systems are evaluated. The various recovery and regeneration techniques of spent adsorbents including magnetic separation, filtration, thermal desorption and decomposition, chemical desorption, supercritical fluid desorption, advanced oxidation process and microbial assisted adsorbent regeneration are discussed in detail. The current challenges for the recovery and regeneration of adsorbents and the methodologies used for solving those problems are covered. The spent adsorbents are managed through regeneration for reuse (such as soil amendment, capacitor, catalyst/catalyst support) or safe disposal involving incineration and landfilling. Sustainable management of spent adsorbents, including processes involved in the recovery and regeneration of adsorbents for reuse, is examined in the context of resource recovery and circular economy. Finally, the review ends with the current drawbacks in the recovery and management of the spent adsorbents and the future directions for the economic and environmental feasibility of the system for industrial-scale application.

Microbial adaptation and impact into the pesticide's degradation

The imprudent use of agrochemicals to control agriculture and household pests is unsafe for the environment. Hence, to protect the environment and diversity of living organisms, the degradation of pesticides has received widespread attention. There are different physical, chemical, and biological methods used to remediate pesticides in contaminated sites. Compared to other methods, biological approaches and their associated techniques are more effective, less expensive and eco-friendly. Microbes secrete several enzymes that can attach pesticides, break down organic compounds, and then convert toxic substances into carbon and water. Thus, there is a lack of knowledge regarding the functional genes and genomic potential of microbial species for the removal of emerging pollutants. Here we address the knowledge gaps by highlighting systematic biology and their role in adaptation of microbial species from agricultural soils with a history of pesticide usage and profiling shifts in functional genes and microbial taxa abundance. Moreover, by co-metabolism, the microbial species fulfill their nutritional requirements and perform more efficiently than single microbial-free cells. But in an open environment, free cells of microbes are not much prominent in the degradation process due to environmental conditions, incompatibilities with mechanical equipment and difficulties associated with evenly distributing inoculum through the agroecosystem. This review highlights emerging techniques involving the removal of pesticides in a field-scale environment like immobilization, biobed, biocomposites, biochar, biofilms, and bioreactors. In these techniques, different microbial cells, enzymes, natural fibers, and strains are used for the effective biodegradation of xenobiotic pesticides.

Cellulose, clay and sodium alginate composites for the removal of methylene blue dye: Experimental and DFT studies

Cellulose/clay/sodium alginate composites were prepared and employed for the removal of methylene blue (MB) dye. Cellulose was extracted from a paper mill waste and used for composite preparation with sodium alginate (Na-Alg) and clay. MB dye removal was analyzed at different operating conditions (pH, initial concentration, temperature, composite dose). This dye was adsorbed up to 90% for an equilibrium time of 60 min at optimum level of adsorbent dose (0.05 g), temperature (30 °C) and pH (i.e., 7 and 11 for cellulose-Na-Alg and cellulose-Na-Alg-clay, respectively). Kinetics and isotherms of MB adsorption were quantified and modeled. Results showed that MB dye adsorption data followed the pseudo-first order kinetics and a statistical physics model was used to analyze the adsorption mechanism. Thermodynamic calculation revealed that the MB dye adsorption on these composites was an exothermic, spontaneous and feasible process. The composites were regenerated with HCl thus contributing to their reutilization in subsequent adsorption cycles. The DFT (density functional theory) calculations were executed to explain the interactions responsible for the adsorption of MB dye on the composites. Results revealed that the Na-Alg-cellulose composites were effective for the MB dye removal. Therefore, these composites can be considered as low-cost alternative adsorbents for the pollution remediation caused by dyes in industrial effluents and wastewater.

An efficient, green and sustainable potassium hydroxide activated magnetic corn cob biochar for imidacloprid removal

The extensive use of imidacloprid (IMI) has led to its being frequently detected in natural water, also caused the potential damage to the ecosystem. Development of efficient, green and sustainable technique is demanded to eliminate this problem. A novel biochar (KMCBC) derived from agriculture waste of corn cob was first time co-modified by potassium hydroxide (KOH), ferric chloride (FeCl₃) and zinc chloride (ZnCl₂), which showed the greater adsorption amount (410 mg g^-1 at 298 K) for imidacloprid (IMI). Pseudo-second-order kinetic and Langmuir isotherm models fitted well with the experimental data, together with the physicochemical characterization analysis, demonstrating that the adsorption process of IMI by KMCBC might be mainly controlled by micropore filling, π-π electron donor-acceptor and functional groups interactions (H-bonding and complexation). Additionally, the thermodynamics parameters suggested that IMI adsorption in this study was a spontaneous, endothermic and randomly increasing process. Besides, KMCBC owned the easy separation performance and promising environmental safety, also exhibited a high selective adsorption capacity regardless of solution pH (its optimum adsorption performance for IMI was obtained at pH = 5), inorganic ions strength and humic acid (HA) concentrations. The regenerated KMCBC (synergistic ultrasound/ethanol) could sustainably and efficiently adsorb IMI in the reuse cycles. Therefore, this study provided an efficient, green and sustainable adsorbent of KMCBC for IMI removal.

Biochar-supported starch/chitosan-stabilized nano-iron sulfide composites for the removal of lead ions and nitrogen from aqueous solutions

Novel materials that nano-FeS and starch (or chitosan) loaded on peanut shells biochar(Starch-FeS@PSB and Chitosan-FeS@PSB) were prepared and applied for removal of Pb(II) and nitrogen(NO₃-N and NH₄-N) in wastewater. It showed that Starch-FeS@PSB and Chitosan-FeS@PSB had excellent absorptive effects compared with PSB. The maximum adsorption capacity of Pb(II) by Starch-FeS@PSB and Chitosan-FeS@PSB reached 91.74 mg/g, 98.04 mg/g, respectively. Absorption of Pb(II) by Starch-FeS@PSB and Chitosan-FeS@PSB were controlled by monolayer chemisorption. Mechanism studies showed that complexation, electrostatic attraction, REDOX and physical absorption happened on the adsorbent surface. In addition, the maximum adsorption capacity of NO₃-N and NH₄-N by Starch-FeS@PSB and Chitosan-FeS@PSB reached 16.89 mg/g, 15.65 mg/g, and 18.45 mg/g, 18.28 mg/g, respectively. Absorption of N by Starch-FeS@PSB and Chitosan-FeS@PSB were controlled by multilayer chemisorption. Mechanism studies showed that complexation, electrostatic attraction and physical absorption happened on the adsorbent surface. Starch-FeS@PSB and Chitosan-FeS@PSB can be utilized in Pb(II) and N wastewater treatment.

The Synthesis of Magnetic Nitrogen-Doped Graphene Oxide Nanocomposite for the Removal of Reactive Orange 12 Dye

Herein, we report the nanofabrication of magnetic calcium ferrite (CaFe2O4) with nitrogen-doped graphene oxide (N-GO) via facile ultrasonication method to produce CaFe2O4/N-GO nanocomposite for the potential removal of reactive orange 12 (RO12) dye from aqueous solution. The successful construction of the nanocomposite was confirmed using different characterization techniques including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform-infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The magnetic properties were studied using vibrating sample magnetometer (VSM) indicating ferromagnetic behavior of the synthesized materials that facilitate their separation using an external magnetic field after adsorption treatment. The addition of N-GO to CaFe2O4 nanoparticles enhanced the BET surface area from 24 to 52.93 m2/g as resulted from the N2 adsorption-desorption isotherm. The adsorption of the synthesized nanomaterials is controlled by several parameters (initial concentration of dye, contact time, adsorbent dosage, and pH), and the RO12 dye removal on the surface of CaFe2O4 nanoparticles and CaFe2O4/N-GO nanocomposite was reached through the chemisorption process as indicated from the kinetic study. The adsorption isotherm study indicated that the adsorption process of RO12 dye was best described through the Langmuir isotherm approving the monolayer adsorption. According to the Langmuir model, the maximum adsorption capacity for RO12 was 250 and 333.33 mg/g for CaFe2O4 nanoparticles and CaFe2O4/N-GO nanocomposite, respectively. The adsorption capacity offered by CaFe2O4/N-GO nanocomposite was higher than reported in the literature for adsorbent materials. Additionally, the regeneration study indicated that CaFe2O4/N-GO nanocomposite is reusable and cost-effective adsorbent. Therefore, the nanofabricated CaFe2O4/N-GO hybrid material is a promising adsorbent for water treatment.

Efficient Recovery of Noble Metal Ions (Pd2+, Ag+, Pt2+, and Au3+) from Aqueous Solutions Using N,N'-Bis(salicylidene)ethylenediamine (Salen) as an Extractant (Classic Solvent Extraction) and Carrier (Polymer Membranes)

This paper presents the results of the first application of N,N'-bis(salicylidene)ethylenediamine (salen) as an extractant in classical liquid-liquid extraction and as a carrier in membrane processes designed for the recovery of noble metal ions (Pd2+, Ag+, Pt2+, and Au3+) from aqueous solutions. In the case of the utilization of membranes, both sorption and desorption were investigated. Salen has not been used so far in the sorption processes of precious metal ions. Recovery experiments were performed on single-component solutions (containing only one type of metal ions) and polymetallic solutions (containing ions of all four metals). The stability constants of the obtained complexes were determined spectrophotometrically. In contrast, electrospray ionization high-resolution mass spectrometry (ESI-HRMS) was applied to examine the elemental composition and charge of the generated complexes of chosen noble metal ions and salen molecules. The results show the great potential of N,N'-bis(salicylidene)ethylenediamine as both an extractant and a carrier. In the case of single-component solutions, the extraction percentage was over 99% for all noble metal ions (molar ratio M:L of 1:1), and in the case of a polymetallic solution, it was the lowest, but over 94% for platinum ions and the highest value (over 99%) for gold ions. The percentages of sorption (%Rs) of metal ions from single-component solutions using polymer membranes containing N,N'-bis(salicylidene)ethylenediamine as a carrier were highest after 24 h of the process (93.23% for silver(I) ions, 74.99% for gold(III) ions, 69.11% and 66.13% for palladium(II) and platinum(II) ions, respectively), similar to the values obtained for the membrane process conducted in multi-metal solutions (92.96%, 84.26%, 80.94%, and 48.36% for Pd(II), Au(III), Ag(I), and Pt(II) ions, respectively). The percentage of desorption (%Rdes) was very high for single-component solutions (the highest, i.e., 99%, for palladium solution and the lowest, i.e., 88%, for silver solution), while for polymetallic solutions, these values were slightly lower (for Pt(II), it was the lowest at 63.25%).

Bio-nanocomposites of graphene with biopolymers; fabrication, properties, and applications

The unique properties of graphene and graphene oxide (GO) nanocomposites make them suitable for a wide range of medical, industrial, and agricultural applications. The addition of graphene or GO to a polymeric matrix can ameliorate its thermo-mechanical, electrical, and barrier characteristics. The present paper reviews the literature on graphene/GO-based bio-nanocomposites and examines the various fabrication methods, such as chemical vapor deposition, chemical synthesis, microwave synthesis, the solvothermal method, molecular beam epitaxy, and colloidal suspension. Each procedure potentially has its disadvantages, especially for mass production. Therefore, introducing an effective method for fabricating graphene on a large scale with high quality is essential. Recent studies have shown that graphene-based bio-nanocomposites are promising materials given their excellent performance in the development of biosensors, drug delivery systems, antimicrobials, modified electrodes, and energy storage systems among other applications. In this review, we evaluate the various procedures used for developing graphene/GO-based bio-nanocomposites and examine the features and applications of the related products. Furthermore, the toxicity of these compounds and attempts to uncover the optimal combinations of biopolymers and carbon nanomaterials for industrial applications will be discussed.

Sodium alginate blended membrane with polyurethane: Desalination performance and antimicrobial activity evaluation

A series of polymeric membranes were synthesized by blending polyurethane with sodium alginate (0.2, 0.4, 0.6, 0.8 and 1.0%). The structural, morphological and thermal properties of the membranes were examined by FTIR, SEM, AFM and TGA, respectively. Performance evaluation (salt rejection and flux) was assessed through reverse osmosis technique (RO). The FTIR spectra of membranes confirmed extensive hydrogen bonding (3350 cm^-1). The SEM and AFM analyses supported a progressively rising surface roughness of blended membranes. The hydrophilicity, crosslinking density and thermal stability of the membranes were improved with an increase in alginate content. The capability of salt (NaCl and MgCl₂) rejection was improved with alginate up to 0.8%. In addition, the rejection of divalent ions was better than monovalent ions (94 ± 0.96% for NaCl and 98 ± 0.98% for MgCl₂). The blended membranes ascertained an effective chlorine resistivity. The antibacterial activity was also promising, which enhanced with the alginate content in the membrane. The sodium alginate blended membrane with polyurethane proved to be an efficient approach to develop the blended membranes with tunable properties for water desalination.

Kinetics, equilibrium and thermodynamics of dyes adsorption onto modified chitosan: a review

In view of promising sorption capacity, stability, biodegradability, cost-effectiveness, environmental friendly nature, regeneration and recycling ability, the chitosan (CS) based adsorbents are highly efficient for the sequestration of dyes. Since CS offers variable chemical structures and CS have been modified by incorporating different moieties. The CS composites with unique properties have been employed successfully for dye adsorption with reasonably high adsorption capacity versus other similar adsorbents. Modifications of CS were promising for the preparation of composites that are extensively studied for their adsorption capacities for various dyes. This review highlights the CS and its modification and their applications for the adsorption of dyes. The removal capacities of CS-based adsorbents, equilibrium modeling, kinetics studies and the thermodynamic characteristics are reported. Moreover, the FTIR, BET, SEM, TGA and XRD were employed for the characterization of CS modified adsorbents are also discussed. Results revealed that the modified CS is highly efficient and can be employed for the sequestration of dyes from effluents.

Kinetics, equilibrium and thermodynamics of dyes adsorption onto modified chitosan: a review

In view of promising sorption capacity, stability, biodegradability, cost-effectiveness, environmental friendly nature, regeneration and recycling ability, the chitosan (CS) based adsorbents are highly efficient for the sequestration of dyes. Since CS offers variable chemical structures and CS have been modified by incorporating different moieties. The CS composites with unique properties have been employed successfully for dye adsorption with reasonably high adsorption capacity versus other similar adsorbents. Modifications of CS were promising for the preparation of composites that are extensively studied for their adsorption capacities for various dyes. This review highlights the CS and its modification and their applications for the adsorption of dyes. The removal capacities of CS-based adsorbents, equilibrium modeling, kinetics studies and the thermodynamic characteristics are reported. Moreover, the FTIR, BET, SEM, TGA and XRD were employed for the characterization of CS modified adsorbents are also discussed. Results revealed that the modified CS is highly efficient and can be employed for the sequestration of dyes from effluents.

Automated knowledge extraction from polymer literature using natural language processing

Materials science literature has grown exponentially in recent years making it difficult for individuals to master all of this information. This constrains the formulation of new hypotheses that scientists can come up with. In this work, we explore whether materials science knowledge can be automatically inferred from textual information contained in journal papers. Using a data set of 0.5 million polymer papers, we show, using natural language processing methods that vector representations trained for every word in our corpus can indeed capture this knowledge in a completely unsupervised manner. We perform time-based studies through which we track popularity of various polymers for different applications and predict new polymers for novel applications based solely on the domain knowledge contained in our data set. Using co-relations detected automatically from literature in this manner thus, opens up a new paradigm for materials discovery.

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Word embeddings trained on a corpus of polymer papers

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Common polymers and their corresponding applications analyzed over time

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Polymer domain knowledge encoded in word vectors

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Novel polymers for certain applications predicted and validated using word embeddings

ZnO, CuO and Fe2O3 green synthesis for the adsorptive removal of direct golden yellow dye adsorption: kinetics, equilibrium and thermodynamics studies

In the present investigation, ZnO, CuO and Fe2O3 were prepared via green route and utilized for the sequestration of DGY (Direct Golden Yellow) dye. Affecting variables i.e., temperature, contact time, adsorbent dose and pH were optimized for maximum sequestration of dye from aqueous medium. The pH 2, adsorbent dose 0.1 g/50 mL dye solution, temperature 30 °C and 50 mg/L dye initial concentration were best levels for efficient dye adsorption and equilibrium was attained in 30 min reaction time. The dye sequestration on to ZnO, CuO and Fe2O3 was an exothermic process. Freundlich and Temkin adsorption isotherms explained well the dye adsorption onto nanoadsorbents and dye adsorption followed pseudo first order kinetic model. Effect of electrolytes and heavy metal ions was also investigated and both affected the adsorption process significantly. In the presences of surfactant/detergent, the removal of dye was reduced and 0.5 N NaOH efficiently desorbed the dye from nanoadsorbents. Findings depicted that the nanoadsorbents are effectual for the sequestration of DGY dye, which can be employed for the remediation of textile effluents.

Biocomposite of sodium-alginate with acidified clay for wastewater treatment: Kinetic, equilibrium and thermodynamic studies

Clay-based composites were prepared, characterized, and applied for the elimination of Blue FBN (BFBN) and Rose FRN (RFRN) dyes. The Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), Thermogravimetric (TGA) and X-ray diffraction analyses were performed to check the interaction of dye molecule with adsorbents. The analysis showed a successful interaction between adsorbent and dyes ions. The experimental data was best fitted with Freundlich isotherm for both dyes (BFBN and RFRN). The findings revealed that at 80 min the adsorption grasped equilibrium in the case of both dyes and succeeded the pseudo-second-order kinetics model. Furthermore, the enthalpy (ΔH°), Gibbs free energy (ΔG°) and entropy (ΔS°) changes suggested that adsorption was exothermic, physical and spontaneous in nature. The maximum adsorption capacities were determined as 76.39% for BFBN and 59.85% for RFRN dye at pH 2.0 and 30 °C. Composites found to be stable at higher temperature and regenerated using MgSO₄ eluting agent. The textile effluent colour was removed up to 50.35 and 54.95% using raw and modified clay, respectively. The modified clay showed promising efficiency for adsorption of synthetic BFBN and RFRN dyes from aqueous solution, which could be a viable option for the treatment of industrial wastewater and textile effluents.

Insights into the Toxicity and Degradation Mechanisms of Imidacloprid Via Physicochemical and Microbial Approaches

Imidacloprid is a neonicotinoid insecticide that has been widely used to control insect pests in agricultural fields for decades. It shows insecticidal activity mainly by blocking the normal conduction of the central nervous system in insects. However, in recent years, imidacloprid has been reported to be an emerging contaminant in all parts of the world, and has different toxic effects on a variety of non-target organisms, including human beings, due to its large-scale use. Hence, the removal of imidacloprid from the ecosystem has received widespread attention. Different remediation approaches have been studied to eliminate imidacloprid residues from the environment, such as oxidation, hydrolysis, adsorption, ultrasound, illumination, and biodegradation. In nature, microbial degradation is one of the most important processes controlling the fate of and transformation from imidacloprid use, and from an environmental point of view, it is the most promising means, as it is the most effective, least hazardous, and most environmentally friendly. To date, several imidacloprid-degrading microbes, including Bacillus, Pseudoxanthomonas, Mycobacterium, Rhizobium, Rhodococcus, and Stenotrophomonas, have been characterized for biodegradation. In addition, previous studies have found that many insects and microorganisms have developed resistance genes to and degradation enzymes of imidacloprid. Furthermore, the metabolites and degradation pathways of imidacloprid have been reported. However, reviews of the toxicity and degradation mechanisms of imidacloprid are rare. In this review, the toxicity and degradation mechanisms of imidacloprid are summarized in order to provide a theoretical and practical basis for the remediation of imidacloprid-contaminated environments.

TV, Huamani-Palomino RG, Baena-Moncada AM. Simultaneous adsorption of a ternary mixture of brilliant green, rhodamine B and methyl orange as artificial wastewater onto biochar from cocoa pod husk waste. Quantification of dyes using the derivative spectrophotometry method

Biochar obtained from cocoa pod husk waste for the simultaneous adsorption of a ternary mixture of brilliant green, rhodamine B and methyl orange.