Recent advances in nanoremediation: Carving sustainable solution to clean-up polluted agriculture soils

Effects of environmental metal and metalloid pollutants on plants and human health: exploring nano-remediation approach

Metal and metalloid pollutants severely threatens environmental ecosystems and human health, necessitating effective remediation strategies. Nanoparticle (NPs)-based approaches have gained significant attention as promising solutions for efficient removing heavy metals from various environmental matrices. The present review is focused on green synthesized NPs-mediated remediation such as the implementation of iron, carbon-based nanomaterials, metal oxides, and bio-based NPs. The review also explores the mechanisms of NPs interactions with heavy metals, including adsorption, precipitation, and redox reactions. Critical factors influencing the remediation efficiency, such as NPs size, surface charge, and composition, are systematically examined. Furthermore, the environmental fate, transport, and potential risks associated with the application of NPs are critically evaluated. The review also highlights various sources of metal and metalloid pollutants and their impact on human health and translocation in plant tissues. Prospects and challenges in translating NPs-based remediation from laboratory research to real-world applications are proposed. The current work will be helpful to direct future research endeavors and promote the sustainable implementation of metal and metalloid elimination.

Integrated Electrochemical Oxidation and Biodegradation for Remediation of a Neonicotinoid Insecticide Pollutant

A novel integrated electrochemical oxidation (EO) and bacterial degradation (BD) technique was employed for the remediation of the chloropyridinyl and chlorothiazolyl classes of neonicotinoid (NEO) insecticides in the environment. Imidacloprid (IM), clothianidin (CL), acetamiprid (AC), and thiamethoxam (TH) were chosen as the target NEOs. Pseudomonas oleovorans SA2, identified through 16S rRNA gene analysis, exhibited the potential for BD. In EO, for the selected NEOs, the total percentage of chemical oxygen demand (COD) was noted in a range of 58-69%, respectively. Subsequently, in the biodegradation of EO-treated NEOs (BEO) phase, a higher percentage (80%) of total organic carbon removal was achieved. The optimum concentration of NEOs was found to be 200 ppm (62%) for EO, while for BEO, the COD efficiency was increased up to 79%. Fourier-transform infrared spectroscopy confirms that the heterocyclic group and aromatic ring were degraded in the EO and further utilized by SA2. Gas chromatography-mass spectroscopy indicated up to 96% degradation of IM and other NEOs in BD (BEO) compared to that of EO (73%). New intermediate molecules such as silanediamine, 1,1-dimethyl-n,n'-diphenyl produced during the EO process served as carbon sources for bacterial growth and further mineralized. As a result, BEO enhanced the removal of NEOs with a higher efficiency of COD and a lower consumption of energy. The removal efficiency of the NEOs by the integrated approach was achieved in the order of AC > CL > IM > TH. This synergistic EO and BD approach holds promise for the efficient detoxification of NEOs from polluted environments.

Mycoremediation of the novel fungicide ametoctradin by different agricultural soils and accelerated degradation utilizing selected fungal strains

Accelerating safety assessments for novel agrochemicals is imperative, advocating for in vitro setups to present pesticide biodegradation by soil microbiota before field studies. This approach enables metabolic profile generation in a controlled laboratory environment eliminating extrinsic factors. In the current study, ten different soil samples were utilized to check their capability to degrade Ametoctradin by their microbiota. Furthermore, five different fungal strains (Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Lasiodiplodia theobromae, and Penicillium chrysogenum) were utilized to degrade Ametoctradin in aqueous media. A degradation pathway was established using the metabolic patterns created during the biodegradation of Ametoctradin. In contrast to 47% degradation (T1/2 of 34 days) when Ametoctradin was left in the soil samples, the fungal strain Aspergillus fumigatus demonstrated 71% degradation of parent Ametoctradin with a half-life (T1/2) of 16 days. In conclusion, soil rich in microorganisms effectively cleans Ametoctradin-contaminated areas while Fungi have also been shown to be an effective, affordable, and promising way to remove Ametoctradin from the environment.

In vivo application of potent probiotics for enhancing potato growth and controlling Ralstonia solanacearum and Fusarium oxysporum infections

Plant probiotics are live microbial cells or cultures that support plant growth and control plant pathogens through different mechanisms. They have various effects on plants, including plant growth promotion through the production of indole acetic acid (IAA), biological control activity (BCA), and production of cellulase enzymes, thus inducing systemic resistance and increasing the availability of mineral elements. The present work aimed to study the potential of Achromobacter marplatensis and Bacillus velezensis as plant probiotics for the field cultivation of potatoes. In vitro studies have demonstrated the ability of selected probiotics to produce IAA and cellulase, as well as antimicrobial activity against two plant pathogens that infect Solanum tuberosum as Fusarium oxysporum and Ralstonia solanacearum under different conditions at a broad range of different temperatures and pH values. In vivo study of the effects of the probiotics A. marplatensis and B. velezensis on S. tuberosum plants grown in sandy clay loamy soil was detected after cultivation for 90 days. Probiotic isolates A. marplatensis and B. velezensis were able to tolerate ultraviolet radiation (UV) exposure for up to two hours, the dose response curve exhibited that the D10 values of A. marplatensis and B. velezensis were 28 and 16 respectively. In the case of loading both probiotics with broth, the shoot dry weight was increased significantly from 28 in the control to 50 g, shoot length increased from 24 to 45.7 cm, branches numbers increased from 40 to 70 branch, leaves number increased from 99 to 130 leaf, root dry weight increased from 9.3 to 12.9 g, root length increased from 24 to 35.7 cm, tuber weight increased from 15 to 37.0 g and tubers number increased from 9 to 24.4 tuber, the rot percentage was reduced to 0%. The addition of both probiotic isolates, either broth or wheat grains load separately has enhanced all the growth parameters; however, better results and increased production were in favor of adding probiotics with broth more than wheat. On the other hand, both probiotics showed a remarkable protective effect against potato pathogens separately and reduced the negative impact of the infection using them together.

In vitro and in vivo evaluation of alginate hydrogel-based wound dressing loaded with green chemistry cerium oxide nanoparticles

Interactive wound dressings have displayed promising outcomes in enhancing the wound healing process. This study focuses on creating a nanocomposite wound dressing with interactive and bioactive properties, showcasing potent antioxidant effects. To achieve this, we developed cerium oxide nanoparticles utilizing curcumin as both the reducing and capping agent. Characterization techniques such as SEM, EDX, DLS, Zetasizer, FTIR, and XRD were utilized to analyze the cerium oxide nanoparticles synthesized through a green approach. The image analysis on the obtained TEM images showed that the curcumin-assisted biosynthesized CeO2NPs have a size of 18.8 ± 4.1 nm. The peaks located at 28.1, 32.7, 47.1, 56.0, 58.7, 69.0, and 76.4 correspond to (111), (200), (220), (311), (222), (400), and (331) crystallographic planes. We applied the Debye-Scherrer equation and observed that the approximate crystallite size of the biosynthesized NPs is around 8.2 nm based on the most intensive broad Bragg peak at 28.1°. The cerium oxide nanoparticles synthesized were integrated into an alginate hydrogel matrix, and the microstructure, porosity, and swelling behavior of the resulting wound dressing were assessed. The characterization analyses provided insights into the physical and chemical properties of the green-synthesized cerium oxide nanoparticles and the alginate hydrogel-based wound dressing. In vitro studies demonstrated that the wound dressing based on alginate hydrogel exhibited favorable antioxidant properties and displayed hemocompatibility and biocompatibility. Animal studies conducted on a rat full-thickness skin wound model showed that the alginate hydrogel-based wound dressing effectively accelerated the wound healing process. Overall, these findings suggest that the alginate hydrogel-based wound dressing holds promise as a highly effective material for wound healing applications.

Management of arsenic-contaminated excavated soils: A review

Ongoing global sustainable development and underground space utilization projects have inadvertently exposed many excavated soils naturally contaminated with geogenic arsenic (As). Recent investigations have revealed that As in certain excavated soils, especially those originating from deep construction projects, has exceeded regulatory limits, threatening the environment and human health. While numerous remediation techniques exist for treating As-contaminated soil, the unique characteristics of geogenic As contamination in excavated soil require specific measures when leachable As content surpasses established regulatory limits. Consequently, several standard leaching tests have been developed globally to assess As leaching from contaminated soil. However, a comprehensive comparative analysis of these methods and their implementation in contaminated excavated soils remains lacking. Furthermore, the suitability and efficacy of most conventional and advanced techniques for remediating As-contaminated excavated soils remained unexplored. Therefore, this study critically reviews relevant literature and summarize recent research findings concerning the management and mitigation of geogenic As in naturally contaminated excavated soil. The objective of this study was to outline present status of excavated soil globally, the extent and mode of As enrichment, management and mitigation approaches for As-contaminated soil, global excavated soil recycling strategies, and relevant soil contamination countermeasure laws. Additionally, the study provides a concise overview and comparison of standard As leaching tests developed across different countries. Furthermore, this review assessed the suitability of prominent and widely accepted As remediation techniques based on their applicability, acceptability, cost-effectiveness, duration, and overall treatment efficiency. This comprehensive review contributes to a more profound comprehension of the challenges linked to geogenic As contamination in excavated soils.

Toxicity assessment of microplastic (MPs); a threat to the ecosystem

Plastic is now considered part and parcel of daily life due to its extensive usage. Microplastic (MP) pollution is becoming a growing worry and has been ranked as the second most critical scientific problem in the realm of ecology and the environment. Microplastics are smaller in size than the plastic and are more harmful to biotic and as well as abiotic environments. The toxicity of microplastic depends upon its shape and size and increases with an increase in its adsorption capacity and their toxicity. The reason behind their harmful nature is their small size and their large surface area-to-volume ratio. Microplastic can get inside fruits, vegetables, seeds, roots, culms, and leaves. Hence microplastic enters into the food chain. There are different entry points for microplastic to enter into the food chain. Such sources can include polluted food, beverages, spices, plastic toys, and household (packing, cooking, etc.). The concentration of microplastic in terrestrial environments is increasing day by day. Microplastic causes the destruction of soil structure; destroys soil microbiota, cause depletion of nutrients in the soil, and their absorption by plants decreases plant growth. Apart from other environmental problems caused by microplastic, human health is also badly affected by microplastic pollution present in the terrestrial environment. The presence of microplastics in the human body has been confirmed. Microplastic enters into the body of humans in different possible ways. According to their way of entering the body, microplastics cause different diseases in humans. MPs also cause negative effects on the human endocrine system. At the ecosystem level, the impacts of microplastic are interconnected and can disrupt ecological processes. Although recently different papers have been published on several aspects of the microplastic present in the terrestrial environment but there is no complete overview that focus on the interrelationship of MPs in plants, and soil and their effect on higher animals like a human. This review provides a completely detailed overview of existing knowledge about sources, occurrences, transport, and effects of microplastic on the food chain and soil quality and their ecotoxicological effects on plants and humans.

Aspergillus niger CJ6 extract with antimicrobial potential promotes in-vitro cytotoxicity and induced apoptosis against MIA PaCa-2 cell line

Nowadays, the increased number of multidrug-resistant strains among pathogens is a severe public health concern and cancer is posing a great threat for humans. These problems should be tackled with the development of novel and broad-spectrum antimicrobials from microbial origin. During the present study, the bioactive secondary metabolites from Aspergillus niger CJ6 were extracted, characterized; their biological properties were evaluated by subjecting them for antimicrobial, antifungal and anticancer activities. The potent isolate Aspergillus niger CJ6 with nucleotide sequence of 959 base pairs showed antagonistic activity against fungal pathogens in dual culture. The chemical profiling of crude ethyl acetate extract indicated the presence of various bioactive molecules belonging to phenolic, hydrocarbons, and phthalate derivative classes. In antimicrobial activity, the crude extract displayed increasing activity with increased concentration; the highest activity observed against Shigella flexneri with 15 ± 1.0, 19 ± 0.5, 20 ± 1.0 and 24 ± 1.0 mm zones of inhibition at 25, 50, 75 and 100 μl concentrations. The MTT assay illustrated deformed cells of MIA PaCa-2 cell line in in-vitro cytotoxic activity; outflow of cell matrix and membrane rupture; the IC₅₀ of 90.78 μg/ml suggested moderate potential of extract to prevent cancer cell growth. The apoptosis/necrosis study by flow cytometer exhibited 8.98 ± 0.85% early and 73 ± 0.7% of late apoptotic population with 3.8 ± 1.1% necrotic cells; only 14.22 ± 0.6% of healthy cells suggested the increased apoptosis inducing capacity of Aspergillus niger CJ6 crude extract. The outcomes of this study persuade further exploration on the identification, purification and development of novel bioactive agents that could help battle fatal diseases in humans.

Environmental safety of nanotechnologies: The eco-design of manufactured nanomaterials for environmental remediation

Nanosafety is paramount considering the risks associated with manufactured nanomaterials (MNMs) whose implications could outweigh their advantages for environmental applications. Although nanotechnology-based solutions to implement pollution control, remediation and prevention are incremental with clear benefits for public health and Earth' natural ecosystems, nanoremediation is having a setback due to the risks associated with the safety of MNMs for humans and the environment. MNMs are diverse, work differently and bionano-interactions occurring upon environmental exposure will guide their fate and hazardous outcomes. Here we propose a new ecologically-based design strategy (eco-design) having its roots in green nanoscience and LCA that will ground on an Ecological Risk Assessment approach, which introduces the evaluation of MNMs' ecotoxicity along with their performances and efficacies at the design stage. As such, the proposed eco-design strategy will allow recognition and design-out since the very beginning of material synthesis, those hazardous peculiar features that can be hazardous to living beings and the natural environment. A more ecologically sound eco-design strategy in which nanosafety is conceptually included in MNMs design will sustain safer nanotechnologies including those for the environment as remediation by leveraging any risks for humans and natural ecosystems.

Recent approaches and advanced wastewater treatment technologies for mitigating emerging microplastics contamination - A critical review

Microplastics have been identified as an emerging pollutant due to their irrefutable prevalence in air, soil, and particularly, the aquatic ecosystem. Wastewater treatment plants (WWTPs) are seen as the last line of defense which creates a barrier between microplastics and the environment. These microplastics are discharged in large quantities into aquatic bodies due to their insufficient containment during water treatment. As a result, WWTPs are regarded as point sources of microplastics release into the environment. Assessing the prevalence and behavior of microplastics in WWTPs is therefore critical for their control. The removal efficiency of microplastics was 65 %, 0.2-14 %, and 0.2-2 % after the successful primary, secondary and tertiary treatment phases in WWTPs. In this review, other than conventional treatment methods, advanced treatment methods have also been discussed. For the removal of microplastics in the size range 20-190 μm, advanced treatment methods like membrane bioreactors, rapid sand filtration, electrocoagulation and photocatalytic degradation was found to be effective and these methods helps in increasing the removal efficiency to >99 %. Bioremediation based approaches has found that sea grasses, lugworm and blue mussels has the ability to mitigate microplastics by acting as a natural trap to the microplastics pollutants and could act as candidate species for possible incorporation in WWTPs. Also, there is a need for controlling the use and unchecked release of microplastics into the environment through laws and regulations.

Synergistic impact of nanomaterials and plant probiotics in agriculture: A tale of two-way strategy for long-term sustainability

Modern agriculture is primarily focused on the massive production of cereals and other food-based crops in a sustainable manner in order to fulfill the food demands of an ever-increasing global population. However, intensive agricultural practices, rampant use of agrochemicals, and other environmental factors result in soil fertility degradation, environmental pollution, disruption of soil biodiversity, pest resistance, and a decline in crop yields. Thus, experts are shifting their focus to other eco-friendly and safer methods of fertilization in order to ensure agricultural sustainability. Indeed, the importance of plant growth-promoting microorganisms, also determined as "plant probiotics (PPs)," has gained widespread recognition, and their usage as biofertilizers is being actively promoted as a means of mitigating the harmful effects of agrochemicals. As bio-elicitors, PPs promote plant growth and colonize soil or plant tissues when administered in soil, seeds, or plant surface and are used as an alternative means to avoid heavy use of agrochemicals. In the past few years, the use of nanotechnology has also brought a revolution in agriculture due to the application of various nanomaterials (NMs) or nano-based fertilizers to increase crop productivity. Given the beneficial properties of PPs and NMs, these two can be used in tandem to maximize benefits. However, the use of combinations of NMs and PPs, or their synergistic use, is in its infancy but has exhibited better crop-modulating effects in terms of improvement in crop productivity, mitigation of environmental stress (drought, salinity, etc.), restoration of soil fertility, and strengthening of the bioeconomy. In addition, a proper assessment of nanomaterials is necessary before their application, and a safer dose of NMs should be applicable without showing any toxic impact on the environment and soil microbial communities. The combo of NMs and PPs can also be encapsulated within a suitable carrier, and this method aids in the controlled and targeted delivery of entrapped components and also increases the shelf life of PPs. However, this review highlights the functional annotation of the combined impact of NMs and PPs on sustainable agricultural production in an eco-friendly manner.

Intimately coupled gC3N4 photocatalysis and mixed culture biofilm enhanced detoxification of sulfamethoxazole: Elucidating degradation mechanism and toxicity assessment

In recent years, wide spread of antibiotic-resistant microorganisms and genes emerging globally, an eco-friendly method for efficient degradation of antibiotics from the polluted environment is essential. Intimately coupled photocatalysis and biodegradation (ICPB) using gC₃N₄ for enhanced degradation of sulfamethoxazole (SMX) was investigated. The gC₃N₄ were prepared and coated on the carbon felt. The mixed culture biofilm was developed on the surface as a biocarrier. The photocatalytic degradation showed 74%, and ICPB exhibited 95% SMX degradation efficiency. ICPB showed superior visible light adsorption, photocatalytic activity, and reduced charge recombination. The electron paramagnetic resonance spectrum confirms that the generation of •OH and O₂• radicals actively participated in the degradation of SMX into biodegradable intermediated compounds, and then, the bacterial communities present in the biofilm mineralized the biodegradable compound into carbon dioxide and water. Moreover, the addition of NO₃^-, PO₄^-, and Cl^- significantly enhanced the degradation efficiency by trapping the surface electron. Stability experiments confirmed that gC₃N₄ biohybrid can maintain 85% SMX degradation efficiency after 5 consecutive recycling. Extracellular polymeric substances characterization results show that biohybrid contains 47 mg/L, 14 mg/L, and 13 mg/L protein, carbohydrate, and humic acid, respectively, which can protect the bacterial communities from the antibiotic toxicity and reactive oxygen species. Furthermore, biotoxicity was investigated using degradation products on E.coli and results revealed 83% detoxification efficiency. Overall, this study suggested that gC₃N₄ photocatalyst in an ICPB can be used as a promising eco-friendly method to degrade sulfamethoxazole efficiently.

Exploring the significance of nanomaterials and organic amendments - Prospect for phytoremediation of contaminated agroecosystem

Emerging micro-pollutants have rapidly contaminated the agro-ecosystem, posing serious challenges to a sustainable future. The vast majority of them have infiltrated the soil and damaged agricultural fields and crops after being released from industry. These pollutants and their transformed products are also transported in vast quantities which further exacerbate the damage. Sustainable remediation techniques are warranted for such large amounts of contaminants. As aforementioned, many of them have been detected at very high concentrations in soil and water which adversely affect crop physiology by disrupting different metabolic processes. To combat this situation, nanomaterials and other organic amendments assisted phytoremediation ware considered as a viable alternative. It is a potent synergistic activity between the biological system and the supplied organic or nanomaterial material to eliminate emerging contaminants and micropollutants from crop fields. This can be effectively be applied to degraded crop fields and could potentially embody a green technology for sustainable agriculture.

Mycodegradation of diazinon pesticide utilizing fungal strains isolated from polluted soil

The current study aimed to isolate biodegradable soil fungi capable of metabolizing diazinon. The collected soil samples were investigated for diazinon pollution to detect the pesticide level in the polluted soil samples. Food poisoning techniques were utilized to preliminary investigate the biodegradation efficiency of the isolated fungal strains to diazinon pesticide using solid and liquid medium and also to detect their tolerance to different concentrations. GC-MS analysis of control and treated flasks were achieved to determine the diazinon residues for confirmation of the biodegradation efficiency. The total diazinon residues in the collected soil samples was found to be 0.106 mg/kg. Out of thirteen fungal strains isolated form diazinon polluted soils, six strains were potentially active in diazinon biodegradation. Food poisoning technique showed that A. niger, B. antennata, F. graminearum, P. digitatum, R. stolonifer and T. viride strains recorded fungal growth diameters of 65.2 ± 0.18, 57.5 ± 0.41, 47.2 ± 0.36, 56.5 ± 0.27, 85.0 ± 0.01, 85.0 ± 0.06 mm respectively in the treated group which were non significantly different compared to that of control (P > 0.05), indicating the high efficiency of these strains in diazinon degradation compared to the other isolated strains. GC-MS analysis revealed that B. antennata was the most efficient strain in diazinon degradation recording 32.24 ± 0.15 ppm concentration after 10 days incubation. Linear regression analysis confirmed that B. antennata was the most effective biodegradable strain recording the highest diazinon dissipation (83.88%) with the lowest T_1/2 value of 5.96 days while T. viride, A. niger, R. stolonifer and F. graminearum exhibited a high biodegradable activities reducing diazinon to 80.26%, 78.22%, 77.36% and 75.43% respectively after 10 days incubation. In conclusion, these tolerant fungi could be considered as promising, eco-friendly and biodegradable fungi for the efficient and potential removal of hazardous diazinon from polluted soil.

An efficient optical properties of Sn doped ZnO/CdS based solar light driven nanocomposites for enhanced photocatalytic degradation applications

Metal sulfide - semiconductor nanocomposites synthesized with well-defined tin metal, exhibited the wide bandgap, the absorptions are limited to the UV-vis region for reduction of Reactive Blue 160 (RB 160) under solar light irradiation. The prepared samples were characterized using optoelectronic techniques. Conveniently, a wider range of wavelengths and physical properties can be enabled by doping these metal oxide nanoparticles. Whereas the photoreduction of RB 160 is unambiguously associated within charge separation and transmission progression from the excited Sn doped ZnO/CdS. Furthermore, Photocatalytic degradation efficiency for the Sn doped ZnO/CdS composites still reliant on the excitation strength, indicating the several electrons and protons were precise as a result of charge separation and transmission in prepared catalyst. Sn doped ZnO/CdS composites shows 94% Photocatalytic degradation efficiency within 120 min under sunlight irradiation. This photocatalytic nanocomposites may find capable applications in solar cells to power stretchable and also in wearable electronics.

Artificial neural network and statistical modelling of biosorptive removal of hexavalent chromium using macroalgal spent biomass

This study focused on the sustainable removal of chromium in its hexavalent form by adsorption using sugar-extracted spent marine macroalgal biomass - Ulva prolifera. The adsorption of Cr (VI) from aqueous solutions utilizing macroalgal biomass was studied under varying conditions of pH, adsorbent amount, agitation speed, and time to assess and optimize the process variables by using a statistical method - response surface methodology (RSM) to enhance the adsorption efficiency. The maximum adsorption efficiency of 99.11 ± 0.23% was obtained using U. prolifera under the optimal conditions: pH: 5.4, adsorbent dosage: 200 mg, agitation speed: 160 rpm, and time: 75 min. Also, a prediction tool - artificial neural network (ANN) model was developed using the RSM experimental data. Eight neurons in the hidden layer yielded the best network topology (4-8-1) with a high correlation coefficient (R_ANN: 0.99219) and low mean squared error (MSE_ANN: 0.99219). Various performance parameters were compared between RSM and ANN models, which confirmed that the ANN model was better in predicting the response with a high coefficient of determination value (R²_ANN: 0.9844, R²_RSM: 0.9721) and low MSE value (MSE_ANN: 3.7002, MSE_RSM: 6.2179). The adsorption data were analyzed by fitting to various equilibrium isotherms. The maximum adsorption capacity was estimated as 6.41 mg/g. Adsorption data was in line with Freundlich isotherm (R² = 0.97) that confirmed the multilayer adsorption process. Therefore, the spent U. prolifera biomass can credibly be applied as a low-cost adsorbent for Cr (VI) removal, and the adsorption process can be modelled and predicted efficiently using ANN.