Conventional Remediation Research Articles

Using Low Molecular Weight Organic Acids to Enhance Microbial Degradation of Polycyclic Aromatic Hydrocarbons: Current Understanding and Future Perspectives

Polycyclic aromatic hydrocarbons (PAHs), an organic pollutant with persistence and carcinogenicity, are universally present in the environment and food processing. Biological approaches toward remediating PAHs-contaminated sites are a viable, economical, and environmentally friendly alternative compared to conventional physical and/or chemical remediation methods. Recently, various strategies relating to low molecular weight organic acids (LMWOAs) have been developed to enhance the microbial degradation of PAHs. However, the remaining challenge is to reveal the role of LMWOAs in the PAHs biodegradation process, and the latter limits researchers from expanding the application scope of biodegradation. In this mini-review, we summarized the current understanding of the impact of LMWOAs on (1) the physicochemical behavior of PAHs in the extracellular environment; (2) the interactions between PAHs and the microbial cell surface; and (3) the intracellular metabolization of PAHs. Future perspectives for this field are discussed in this review as well.

Nutshells as Efficient Biosorbents to Remove Cadmium, Lead, and Mercury from Contaminated Solutions.

The release of potentially toxic elements into the environment, and their effects on aquatic ecosystems still present a real threat. To avoid such contamination, the use of biological sorbents as an alternative to conventional and expensive water remediation techniques has been proposed. The present study evaluated the potential of 0.5 g L−1 of peanut, hazelnut, pistachio, walnut, and almond shells to remove the requisite concentrations of cadmium (Cd), lead (Pb), and mercury (Hg) from contaminated water. Hazelnut shells were identified as the sorbent with the highest potential and were evaluated in mono- and multi-contaminated mineral water. The influence of sorbent-intrinsic and solution-intrinsic characteristics were assessed. Differences among sorbents were attributed to varying percentages of their main components: cellulose, hemicellulose, and lignin. Matrix complexity increase caused a decrease in Cd removal, presumably due to the diminution in electrostatic interaction, and complexation with anions such as Cl−. When simultaneously present in the solution, contaminants competed, with Pb showing higher affinity to the sorbent than Hg. High efficiencies (>90%) obtained for hazelnut shells for all elements in ultrapure water and for Pb and Hg in mineral water) reveals the high potential of this low-cost and abundant waste for use in the remediation of contaminated waters (circular economy).

Study on aerobic degradation of 2,4,6-trinitrotoluene (TNT) using Pseudarthrobacter chlorophenolicus collected from the contaminated site.

2,4,6-trinitrotoluene or TNT, a commonly used explosive, can pollute soil and groundwater. Conventional remediation practices for the TNT-contaminated sites are neither eco-friendly nor cost-effective. However, exploring bacteria to biodegrade TNT into environment-friendly compound(s) is an interesting area to explore. In this study, an indigenous bacterium, Pseudarthrobacter chlorophenolicus, strain S5-TSA-26, isolated from explosive contaminated soil, was investigated for potential aerobic degradation of TNT for the first time. The isolated strain of P. chlorophenolicus was incubated in a minimal salt medium (MSM) containing 120mg/L TNT for 25days at specified conditions. TNT degradation pattern by the bacterium was monitored at regular interval using UV-Vis spectrophotometry, high-performance liquid chromatography, and liquid chromatography mass spectrophotometric, by estimating nitrate, nitrite, and ammonium ion concentration and other metabolites such as 2,4-dinitrotoluene (DNT), 2-amino-4,6-dinitrotoluene (2-ADNT), and 2,4-diamino-6-nitrotoluene (2-DANT). It was observed that, in the presence of TNT, there was no reduction in growth of the bacterium although it multiplied well in the presence of TNT along with no considerable morphological changes. Furthermore, it was found that TNT degraded completely within 15days of incubation. Thus, from this study, it may be concluded that the bacterium has the potential for degrading TNT completely with the production of non-toxic by-products and might be an important bacterium for treating TNT (i.e., a nitro-aromatic compound)-contaminated sites.

The biotechnology approach for sustainable concrete material – a review

Biomineralisation is a process of formation of calcite from supersaturated solution due to the presence of bacterial cells and biochemical activities. In this article, a biological approach towards the development of sustainable construction materials is studied. Evidence of bacterial precipitation of calcite has led several research groups to explore the possibility of adopting this process in the area of construction materials. The goal of this review paper is to highlight the application of biomineralisation in concrete. The effect of a bio-based agent and bacterial solution on various properties of concrete is discussed. Additionally, the factors in the choice of bacteria for the biomineralisation process are also elaborated. This green biotechnology concept is a promising, environmentally safe substitute for conventional and current remediation methods to mitigate environmental problems in multidisciplinary fields.

Rhizofiltration for Removal of Inorganic and Organic Pollutants in Groundwater: a Review

Groundwater serves as the water recharge of surface water and provides clean water for domestic, industrial, and agricultural usage for human life. However, rapid developments resulted in groundwater contamination by heavy metals, pesticides, waste by-products, cosmetics, pharmaceutics, and biological agents. Groundwater contamination by the percolation of heavy metals (HM) is focused on in this review. Heavy metals known for their persistence, bioaccumulation, and biomagnification properties are hazardous to live organisms. Long-term exposure to heavy metals brings adverse effects on respiratory diseases, cardiovascular disorders, cancer, etc. They are considered toxins, carcinogens, mutagens, and teratogens for humans in low concentrations. Hence, technologies to remediate heavy metals and organic pollutant in groundwater is vital to prevent environmental and health issues. However, current conventional remediation technologies that are expensive, utilize hazardous materials, and produce toxic by-products in effluents are insufficient to alleviate heavy metals' effects in groundwater. Thus, an eco-friendly and cost-effective rhizofiltration method that adsorb, concentrate, and precipitate contaminants in or on plants' rhizosphere is introduced. This review portrays the mechanisms involved in rhizofiltration to remediate heavy metals-contaminated groundwater and describes the gaps for rhizofiltration to be a commercially viable technology.

Biosorption and removal of toxic heavy metals by metal tolerating bacteria for bioremediation of metal contamination: A comprehensive review

Heavy metal pollution caused due to the industrialization has been considered as a significant public health hazard, and these heavy metals exhibit various types of toxicological manifestations. Conventional remediation methods are expensive and also yield toxic by-products, which negatively affect the environment. Hence, a green technology employing various biological agents, predominantly bacteria, algae, yeasts, and fungi, has received more attention for heavy metal removal and recovery because of their high removal efficiency, low cost, and availability. However, bacterial biosorption is the safest treatment method for the toxic pollutants that are not readily biodegradable such as heavy metals. Metal biosorption by bacteria has received significant attention due to a safe, productive, and feasible technology for the heavy metal-containing wastewater treatment. These metal tolerating bacteria can bind the cationic toxic heavy metals with the negatively charged bacterial structures and live or dead biomass components. Due to the large surface area to volume ratio, these bacterial biomasses efficiently act as the biosorbent for metal bioremediation under multimetal conditions. This review summarizes the biosorption potentials of bacterial biomass towards different metal ions, cell wall constituent, biofilm, extracellular polymeric substances (EPS) in metal binding, and the effect of various environmental parameters influencing the metal removal. Suitable mathematical models of biosorption and their application have been discussed to understand and interpret the adsorption process. Furthermore, different desorbing agents and their utilization in heavy metals recovery and regeneration of biosorbent have been summarized.

Phytoremediation: sustainable approach for the removal of Heavy metals from the environment using plants

These studies Review the plant species for phytoremediation potential and capability to consumption and accrue Heavy metals concentration. Natural renewable resources are valuable assets for human development. Extreme utilization of the resources and severely contaminated due to the influence of human activity on nature. Resources Contamination with toxic metals is a wide-ranging environmental issue resultant from various sources like Inorganic fertilizer, pesticides, leaching, and dumping of pollutants. The Remediation of sites polluted with toxic metals is predominantly difficult. Conventional techniques for recovery are expensive and environmentally uncongenial. Plant-based technology known as Phytoremediation has been proposed as an economical environment-friendly alternative technology to the conventional remediation approaches.

In vitro microcosm of co-cultured bacteria for the removal of hexavalent Cr and tannic acid: A mechanistic approach to study the impact of operational parameters

Industrial wastes, for instance, tannery wastes are rich soups of resistant and bioremediation-potent bacteria. In the present work, Chromium (Cr) and tannic acid (TA) resistance bacterial strains were isolated from tannery effluent and identified as Bacillus subtilis (MCC 3275) and Bacillus safensis (MCC 3283) based on its 16S Ribosomal RNA homology. Hexavalent Cr is highly toxic and mutagenic due to its high mobility and reactivity. Whereas, TA is known to inhibit enzyme activity, substrate deprivation, and interaction with membranes and matrix-metal ions. The developed In vitro co-cultured microcosm of B. subtilis and B. safensis was able to remove Cr(VI) up to 95% and TA up to 23%. The bacteria cultures separately were able to degrade Cr(VI) to 88% by B. subtilis and 91% by B. safensis and TA up to 27%. Plackett Burman design (PBD) followed by Response surface methodology (RSM) was applied for the optimization of physio-chemical parameters. The optimized conditions for co-culture development were recorded as K2HPO4 = 0.2 g/L, MgSO4 = 0.2 g/L, NH4Cl = 0.5 g/L, glucose – 0.2 g/L, TA – 5%, Cr = 200 ppm, incubation period of 96 h, agitation speed of 110 rpm, pH = 5.0, temperature= 30 °C and inoculum size = 3%. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) revealed the thorough mechanism of cellular uptake followed by degradation of Cr(VI) and TA. The efficiency of co-culture for other heavy metals was observed as follows: Zn 65%, Pb 63%, Cd 65%, and Ni 65%. Bioremediation using bacteria is an economical and environmentally better alternative to conventional remediation methods. The isolated bacteria are useful in the effluent treatment of tannery or related industries and in metal recovery in mining processes.

Application of Hybrid Membrane Processes Coupling Separation and Biological or Chemical Reaction in Advanced Wastewater Treatment.

The rapid urbanization and water shortage impose an urgent need in improving sustainable water management without compromising the socioeconomic development all around the world. In this context, reclaimed wastewater has been recognized as a sustainable water management strategy since it represents an alternative water resource for non-potable or (indirect) potable use. The conventional wastewater remediation approaches for the removal of different emerging contaminants (pharmaceuticals, dyes, metal ions, etc.) are unable to remove/destroy them completely. Hybrid membrane processes (HMPs) are a powerful solution for removing emerging pollutants from wastewater. On this aspect, the present paper focused on HMPs obtained by the synergic coupling of biological and/or chemical reaction driven processes with membrane processes, giving a critical overview and particular emphasis on some case studies reported in the pertinent literature. By using these processes, a satisfactory quality of treated water can be achieved, permitting its sustainable reuse in the hydrologic cycle while minimizing environmental and economic impact.

Brevundimonas diminuta MYS6 associated Helianthus annuus L. for enhanced copper phytoremediation

Natural occurring metal-tolerant microbial population have replaced conventional expensive metal remediation approach since the last few years. The present study focuses on investigating the potential of a copper-tolerant plant growth promoting rhizobacterial strain Brevundimonas diminuta MYS6 for Cu bioremediation, plant growth promotion and Cu uptake in Helianthus annuus L. Box-Behnken Design of response surface methodology optimized the influencing parameters such as pH, temperature and Cu concentration. At optimized conditions of pH (5), temperature (32.5 °C) and Cu concentration (250 mg/L), the rhizobacteria followed a sigmoid growth curve pattern with maximum Cu removal of 94.8% in the stationary phase of growth. Cu exposed Brevundimonas diminuta MYS6 produced increased EPS (18.6%), indicating their role in internal defence against Cu stress. The FTIR analysis suggested the role of carboxylic acids, alcohols and aliphatic amine groups in Cu bioremoval. Furthermore, the results of pot experiments conducted with Helianthus annuus L. var. CO4 and Brevundimonas diminuta MYS6 showed enhanced plant growth and Cu uptake. The rhizobacteria increased root and shoot length, fresh and dry plant biomass and leaf chlorophyll by 1.5, 1.7, 9.9, 15.8 and 2.1 fold. The plant biomass mediate enhanced Cu uptake in roots and shoots was found to be 2.98 and 4.1 folds higher when compared to non-inoculated treatment. Henceforth the results of the study evidence the rhizobacterial strain Brevundimonas diminuta MYS6 as an efficient bio-inoculant for copper remediation.

Adsorption and desorption of water-soluble naphthenic acid in simulated offshore oilfield produced water

The removal of water-soluble organics compounds in oilfield produced water (OPW) is currently one of the biggest challenges to meet the environmental legislation, as conventional remediation focuses mainly on removing solids and the dispersed oil fraction. Naphthenic acids (NAs) are present in significant amounts in water-soluble organics compounds; therefore, this work milestone is to properly understand the adsorption process by using an acutely recalcitrant O2-NA as WSO model. For this, a comprehensive screening of commercial adsorbents and waste was tested for NAs remediation, assessing also the influence of adsorbent properties and functionalities. Afterwards, there were selected the resins MN 202 and L 493 as adsorbents to further evaluate the regeneration and other variables such as temperature, pH and salt content, focusing on on-site offshore conditions. The initial screening and the equilibrium data suggest that characteristics such as surface area, pore diameter, and ionic form have a great influence on the adsorption process. Furthermore, the adsorption mechanisms involve anion exchange and hydrophobic interactions, showing a transition between multilayer to monolayer adsorption with the increase of the adsorbent dosage and the kinetics, while increasing NA encourages pore diffusion, resulting in irreversible adsorption. The use of eluents, while avoiding irreversible adsorption, allows recovering the adsorbent, improving the process feasibility at the targeted conditions.

Enzymatic technologies as green and sustainable techniques for remediation of oil-contaminated environment: state of the art

The consistent discharge of xenobiotic compounds including hydrocarbon-containing substances, pesticides, plastics, fertilizers, etc., in the surrounding is the main source of pollution in our ecosystem and must be eradicated and controlled. Numerous conventional remediation strategies such as biological, chemical and physical techniques have been adopted and are presently in use. However, several limitations attached to the utilization of the aforementioned techniques had led to the fervent search for more cost-effective and efficient methods. Enzyme-based remediation is an eco-friendly, quick, easy and acceptable strategy utilized for the degradation of these contaminants in the ecosystem. Numerous enzymes with potent biodegradation potentials have been identified and distinguished from their innate sources; conversely, less extraction of these enzymes has limited further exploitation of the enzymes. More recently, research has shown that genetic engineering strategy has the capacity to produce numerous types of enzymes. In addition, enzyme immobilization techniques can be used to enhance the stability, half-life and overall catalytic rate of enzymes. In this current appraisal, we have presented a concise overview of the enzymes used for the remediation of hazardous and toxic contaminants. The comprehension of the mode of action of enzymatic bioremediation of enzymes like tyrosinase, laccase, peroxidase, oxygenase has also been extensively revealed in this current review. Diverse enzyme methods (enzyme immobilization and engineering) are used to overcome those limitations. Hopefully, this appraisal will expose the world to considerable description about enzymes and numerous enzymatic technologies which can be utilized for the remediation of pollutants in the ecosystem.

Phytoremediation Mechanisms in Air Pollution Control: a Review

Air pollutants originated from natural and anthropogenic sources and able to bio-magnify and bio-accumulate in the trophic levels, thus increase toxicity in the food chain. Various air pollutants (particulate matters (PMs), volatile organic compounds (VOCs), inorganic air pollutants (IAP), persistent organic pollutants (POPs), heavy metals, and black carbon) resulted in adverse effects on environmental and human health after prolonged exposure. These airborne particles can travel in gaseous form for long distance and deteriorate the air quality of downstream areas. Air pollution abatement can be implemented by reducing emissions at source and purifying pollutants with remediation techniques. However, air pollution remained as the dominant issue to cause burden in human and ecosystem well-being. Due to drawbacks like expensive, high maintenance, and likelihood for pollutants’ reemission, existing conventional remediation technologies is insufficient for air pollutants mitigation. Phytoremediation enters the picture of air pollution control as a cost-effective, energy-saving, and environmental-friendly technology in remediating air pollutants. In phytoremediation, plant organs and associating microbes in the phyllosphere and rhizosphere interacted with each other to remediate air pollutants. Phytoremediation of air pollutants involves the rhizosphere of plants as pollutants may deposit in the soil during leaf fall and precipitation. Additionally, the phytoremediation mechanisms involve phytoextraction, phytovolatilization, phytodegradation, phytostabilization, rhizodegradation, and rhizofiltration. A brief overview of phytoremediation mechanisms for each air pollutants is presented. In short, the benefits of phytoremediation and its associated gaps in air pollution control are described.

Acid Mine Drainage Remediation: Aluminum Chelation Using Functional Graphenic Materials.

Acid mine drainage (AMD) is a pervasive source of metal pollution that severely impacts freshwater ecosystems and has a direct impact on human health. Conventional active and passive methods work very well for removing iron in AMD remediation, which is typically the highest metallic impurity. However, conventional passive remediation fails to remove all aluminum, which has severe ecological implications. Removal of aluminum ions using chelation, which traditionally uses small molecules that bind metals tightly for sequestration, holds promise. Yet, chelation strategies are limited because once introduced into surface water, small molecules are difficult to reclaim and often persist in the environment as pollutants. To address this, we have designed six unique scaffolds based on functional graphenic materials (FGMs) to create nonsoluble materials that could be placed at the end of a passive remediation process to remove persistent aluminum. When tested for efficacy, all six FGMs successfully demonstrated a reversible capacity to remove aluminum from acidic water, chelating up to 21 μg of Al/mg of FGM. Furthermore, when they were exposed to E. coli as an approximation for environmental compatibility, viability was unaffected, even at high concentrations, suggesting these FGMs are nontoxic and viable candidates for passive chelation-based remediation.

Enhanced catalytic degradation of organic pollutants by multi-stimuli activated multiferroic nanoarchitectures

Smart catalysts that can simultaneously utilize multiple energy sources will have a significant positive impact on the inefficiencies of conventional environmental remediation approaches, and will address their high energy demands. In this work, we have manufactured multiferroic magnetoelectric photocatalysts that can be simultaneously activated using multiple energy sources for the degradation of organic pollutants. The catalysts are composed of CoFe2O4@BiFeO3 (CFO@BFO) nanooctahedrons (NOs), CFO@BFO nanocubes (NCs), and CFO@BFO nanowires (NWs), and were successful in harnessing energy from three different energy sources, including UV-vis light, acoustically mediated mechanical vibrations and magnetic fields. The CFO@BFO NOs displayed the most enhanced degradation, reaching 93%, 96%, and 99% degradation of RhB dye within 1 h under light, ultrasound, and magnetic fields, respectively. When these energy sources were used simultaneously, significantly increased reaction rates were observed compared to the single-energy source stimulation. Results of radical trapping experiments indicate that radical species i.e., OH· and O2·- play a dominant role in catalytic degradation of organic pollutant, RhB, under all three stimuli. These results will contribute significantly to the development of new environmental technologies that are highly versatile in nature and able to adapt to changing environments to deliver efficient environmental remediation.

Decontamination of xenobiotics in water and soil environment through potential application of composite maize stover/rice husk (MS/RH) biochar-a review.

Industries continuously emit xenobiotics into the environment, which increases risks of exposing humans and other biota to xenobiotics. Though various conventional and modern environmental remediation technologies are being employed, some of them are ineffective in removing xenobiotics, while others are costly and not feasible for large-scale utilization. Maize stover (MS) and rice husks (RH) are produced in abundance globally, which make them ideal and cost-effective feedstocks for large-scale biochar production for environmental remediation. Since either type of pristine MS and RH biochar may not be effective in removing some xenobiotics, the incorporation of modifiers into MS/RH biochars can help to form composite MS/RH biochar which in turn can better decontaminate water and soil. Thus, this review paper provides a comprehensive overview of the preparation, characterization, and environmental remediation using pristine and composite MS/RH biochar. Possible areas for composite MS/RH biochar applications and future perspectives of the technology in reducing xenobiotics are also proposed in this paper.

Conventional and emerging technologies for removal of antibiotics from wastewater

Antibiotics and pharmaceuticals related products are used to enhance public health and quality of life. The wastewater that is produced from pharmaceutical industries still contains noticeable amount of antibiotics, and this has remained one of the major environmental problems facing public health. The conventional wastewater remediation approach employed by the pharmaceutical industries for the antibiotics wastewater removal is unable to remove the antibiotics completely. Besides, municipal and livestock wastewater also contain unmetabolized antibiotics released by human and animal, respectively. The antibiotic found in wastewater leads to antibiotic resistance challenges, also emergence of superbugs. Currently, numerous technological approaches have been developed to remove antibiotics from the wastewater. Therefore, it was imperative to critically review the weakness and strength of these current advanced technological approaches in use. Besides, the conventional methods for removal of antibiotics such as Klavaroti et al., Homem and Santos also discussed. Although, membrane treatment is discovered as the ultimate choice of approach, to completely remove the antibiotics, while the filtered antibiotics are still retained on the membrane. This study found, hybrid processes to be the best solution antibiotics removal from wastewater. Nevertheless, real-time monitoring system is also recommended to ascertain that, wastewater is cleared of antibiotics.

Nanotechnology to remove polychlorinated biphenyls and polycyclic aromatic hydrocarbons from water: a review

Persistent pollutants cause adverse effects to human and environmental health. Most polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH) are toxic and stable in the environment, yet their removal is rarely targeted by conventional remediation methods. Alternatively, nanotechnology appears promising for contaminant removal. Indeed, nanomaterials have unique size-dependent properties due to their high specific surface area. Nanomaterials also possess fast dissolution properties, strong sorption, supermagnetic characteristics and quantum confinement. This manuscript reviews the application of nanotechnologies for the removal of PCB and PAH from contaminated water sources.

Biofiltration of oil sands process water in fixed-bed biofilm reactors shapes microbial community structure for enhanced degradation of naphthenic acids

Naphthenic acids (NAs) are a complex mixture of carboxylic acids present in oil sands process water (OSPW). Their recalcitrant nature makes them difficult to be removed from the environment using conventional remediation strategies. This study hypothesized that, upon continuous operation, biofiltration of OSPW in fixed-bed biofilm reactors would allow the development of NA-degrading microbial community within the biofilter following successful removal. Both raw and ozonated OSPW were treated in the biofilters and changes in microbial community were tested via 16S/18S amplicon sequencing and metatranscriptomics. Through switch from suspended growth to attached growth, a shift in indigenous microbial community was seen following by an increase in alpha diversity. Concomitantly, improved degradation of NAs was monitored, i.e., 35.8% and 69.4% of NAs were removed from raw and ozonated OSPW, respectively. Metatranscriptomics analysis suggested the presence of genes involved in the degradation of organic acids and petroleum-related compounds. Specifically, functional abundance of aromatic compounds' metabolism improved from 0.05% to 0.76%; whereas abundance of benzoate transport and degradation pathway increased from 0.04% to 0.64%. These changes conclude that continuous operation of OSPW in the bioreactors was in favor of shaping the overall microbiome towards better NA degradation.

Process optimization of silica encapsulation technique as a unique remediation technology for the treatment of crude oil contaminated soil

The effect of hydrocarbon pollution on soil quality is globally challenging. Addressing the menace of pollution on soil necessitates research into the development of viable remediation technique that is fast, effective, efficient and environmentally friendly; with cutting edge advantages over conventional remediation techniques. The technique was designed using a formulated silica encapsulating product and applied on soil contaminated by simulation with 10% crude oil. Soil was characterized for its physicochemical properties using standard methods, while its TPH content determined by molecular spectroscopy. Properties such as conductivity, pH and phosphorus levels were severely impacted by the hydrocarbon effect. Silica encapsulating product was formulated from sodium silicate and sodium dodecyl sulphate using proper optimization procedures. The encapsulating product (sodium silicate and SDS) were used in a ratio of 1:2. Optimum concentrations of 60,000 ppm sodium silicate solution, 120,000 ppm SDS, applied at optimum pH and temperature of 5 and 25 °C respectively were established from the process optimization of the experimental technique. The technique shows rapid response towards TPH removal, as 86.79% TPH reduction is achieved after seven days of treatment. The encapsulation process follows pseudo first order kinetics. Significant reduction in metals; Ni (0.61–0.036 mg/kg), V (0.82–0.11 mg/kg) and Cd (0.05–0.016 mg/kg) shows the efficacy of the technique, thereby providing a dual alternative for the remediation of hydrocarbons and heavy metals. The technique seems to be effective in restoring some lost soil properties as seen in pH, conductivity and total nitrogen after treatment. The environmental friendliness, cost effectiveness and merits associated with this technique gives it a unique advantage over other conventional methods; as such presents promising alternative route for remediation experts in addressing the challenges associated with hydrocarbon and metals pollution on soil. Silica encapsulation technique is therefore suitable for outright applications in real field challenges.