Zero-valent iron (ZVI) facilitated in-situ selenium (Se) immobilization and its recovery by magnetic separation: Mechanisms and implications for microbial ecology.

Selenium (Se(VI)) is environmentally toxic. One of the most popular reducing agents for Se(VI) remediation is zero-valent iron (ZVI). However, most ZVI studies were carried out in water matrices, and the recovery of reduced Se has not been investigated. A water-sediment system constructed using natural sediment was employed here to study in-situ Se remediation and recovery. A combined effect of ZVI and unacclimated microorganisms from natural sediment was found in Se(VI) removal in the water phase with a removal efficiency of 92.7 ± 1.1% within 7 d when 10 mg L-1 Se(VI) was present. Soluble Se(VI) was removed from the water and precipitated to the sediment phase (74.8 ± 0.1%), which was enhanced by the addition of ZVI (83.3 ± 0.3%). The recovery proportion of the immobilized Se was 34.2 ± 0.1% and 92.5 ± 0.2% through wet and dry magnetic separation with 1 g L-1 ZVI added, respectively. The 16 s rRNA sequencing revealed the variations in the microbial communities in response to ZVI and Se, which the magnetic separation could potentially mitigate in the long term. This study provides a novel technique to achieve in-situ Se remediation and recovery by combining ZVI reduction and magnetic separation.

A sustainable bioprocess to produce bacterial cellulose (BC) using waste streams from wine distilleries and the biodiesel industry: evaluation of BC for adsorption of phenolic compounds, dyes and metals.

BACKGROUND: The main challenge for large-scale production of bacterial cellulose (BC) includes high production costs interlinked with raw materials, and low production rates. The valorization of renewable nutrient sources could improve the economic effectiveness of BC fermentation while their direct bioconversion into sustainable biopolymers addresses environmental pollution and/or resource depletion challenges. Herein a green bioprocess was developed to produce BC in high amounts with the rather unexplored bacterial strain Komagataeibacter rhaeticus, using waste streams such as wine distillery effluents (WDE) and biodiesel-derived glycerol. Also, BC was evaluated as a bio-adsorbent for phenolics, dyes and metals removal to enlarge its market diversification. RESULTS: BC production was significantly affected by the WDE mixing ratio (0-100%), glycerol concentration (20-45 g/L), type of glycerol and media-sterilization method. A maximum BC concentration of 9.0 g/L, with a productivity of 0.90 g/L/day and a water holding capacity of 60.1 g water/g dry BC, was achieved at 100% WDE and ≈30 g/L crude glycerol. BC samples showed typical cellulose vibration bands and average fiber diameters between 37.2 and 89.6 nm. The BC capacity to dephenolize WDE and adsorb phenolics during fermentation reached respectively, up to 50.7% and 26.96 mg gallic acid equivalents/g dry BC (in-situ process). The produced BC was also investigated for dye and metal removal. The highest removal of dye acid yellow 17 (54.3%) was recorded when 5% of BC was applied as the bio-adsorbent. Experiments performed in a multi-metal synthetic wastewater showed that BC could remove up to 96% of Zn and 97% of Cd. CONCLUSIONS: This work demonstrated a low-carbon approach to produce low-cost, green and biodegradable BC-based bio-adsorbents, without any chemical modification. Their potential in wastewater-treatment-applications was highlighted, promoting closed-loop systems within the circular economy era. This study may serve as an orientation for future research towards competitive or targeted adsorption technologies for wastewater treatment or resources recovery.

Urban mining of municipal solid waste incineration (MSWI) residues with emphasis on bioleaching technologies: a critical review.

Metals are essential in our daily lives and have a finite supply, being simultaneously contaminants of concern. The current carbon emissions and environmental impact of mining are untenable. We need to reclaim metals sustainably from secondary resources, like waste. Biotechnology can be applied in metal recovery from waste streams like fly ashes and bottom ashes of municipal solid waste incineration (MSWI). They represent substantial substance flows, with roughly 46 million tons of MSWI ashes produced annually globally, equivalent in elemental richness to low-grade ores for metal recovery. Next-generation methods for resource recovery, as in particular bioleaching, give the opportunity to recover critical materials and metals, appropriately purified for noble applications, in waste treatment chains inspired by circular economy thinking. In this critical review, we can identify three main lines of discussion: (1) MSWI material characterization and related environmental issues; (2) currently available processes for recycling and metal recovery; and (3) microbially assisted processes for potential recycling and metal recovery. Research trends are chiefly oriented to the potential exploitation of bioprocesses in the industry. Biotechnology for resource recovery shows increasing effectiveness especially downstream the production chains, i.e., in the waste management sector. Therefore, this critical discussion will help assessing the industrial potential of biotechnology for urban mining of municipal, post-combustion waste.

Natural Materials Modified and Applied to the Detection of Drugs In Situ: Modification of Eggshell and Quantification of Oxytetracycline.

This work describes a novel sensing system using eggshells as substrate for the first time, targeting the detection and semiquantitative determination of antibiotics in waters from aquaculture, enabling simple, inexpensive, and in situ drug monitoring. Eggshell was ground and the resulting powder was modified by adsorption of suitable reagents, and it takes a typical colour after contact with the antibiotic. The colour intensity is correlated with the concentration of the antibiotic. This novel approach was applied to oxytetracycline, one of the antibiotics commonly used in aquaculture. The chemical changes on the eggshell powder were evaluated and optimised to produce an intense colour change as a function of the concentration of the antibiotic. The colour changes were evaluated by visual comparison with images taken with a digital camera, applying an appropriate mathematical treatment to the colour coordinates of the HSL system used by Windows. The selectivity of the response was tested against other antibiotic drugs. The materials were also used in the analysis of a spiked environmental water sample. Overall, this work presents a rapid, inexpensive, simple and equipment-free method for screening and discrimination of tetracycline drugs in aquaculture. The method is a green approach by reusing eggshells and decreasing the level of contamination correlated to analytical methods, thus being a promising tool for local, rapid, and cost-effective antibiotic monitoring.

Selenium (Se) recovery for technological applications from environmental matrices based on biotic and abiotic mechanisms.

Selenium (Se) is an essential element with application in manufacturing from food to medical industries. Water contamination by Se is of concern due to anthropogenic activities. Recently, Se remediation has received increasing attention. Hence, different types of remediation techniques are listed in this work, and their potential for Se recovery is evaluated. Sorption, co-precipitation, coagulation and precipitation are effective for low-cost Se removal. In photocatalytic, zero-valent iron and electrochemical systems, the above mechanisms occur with reduction as an immobilization and detoxification process. In combination with magnetic separation, the above techniques are promising for Se recovery. Biological Se oxyanions reduction has been widely recognized as a cost-effective method for Se remediation, simultaneously generating biosynthetic Se nanoparticles (BioSeNPs). Increasing the extracellular production of BioSeNPs and controlling their morphology will benefit its recovery. However, the mechanism of the microbial production of BioSeNPs is not well understood. Se containing products from both microbial reduction and abiotic methods need to be refined to obtain pure Se. Eco-friendly and cost-effective Se refinery methods need to be developed. Overall, this review offers insight into the necessity of shifting attention from Se remediation to Se recovery.

Research Trends and Future Perspectives in Marine Biomimicking Robotics.

Mechatronic and soft robotics are taking inspiration from the animal kingdom to create new high-performance robots. Here, we focused on marine biomimetic research and used innovative bibliographic statistics tools, to highlight established and emerging knowledge domains. A total of 6980 scientific publications retrieved from the Scopus database (1950-2020), evidencing a sharp research increase in 2003-2004. Clustering analysis of countries collaborations showed two major Asian-North America and European clusters. Three significant areas appeared: (i) energy provision, whose advancement mainly relies on microbial fuel cells, (ii) biomaterials for not yet fully operational soft-robotic solutions; and finally (iii), design and control, chiefly oriented to locomotor designs. In this scenario, marine biomimicking robotics still lacks solutions for the long-lasting energy provision, which presently hinders operation autonomy. In the research environment, identifying natural processes by which living organisms obtain energy is thus urgent to sustain energy-demanding tasks while, at the same time, the natural designs must increasingly inform to optimize energy consumption.

Silver Nanoparticles as Carriers of Anticancer Drugs for Efficient Target Treatment of Cancer Cells.

Since the last decade, nanotechnology has evolved rapidly and has been applied in several areas, such as medicine, pharmaceutical, microelectronics, aerospace, food industries, among others. The use of nanoparticles as drug carriers has been explored and presents several advantages, such as controlled and targeted release of loaded or coupled drugs, and the improvement of the drug's bioavailability, in addition to others. However, they also have some limitations, related to their in vivo toxicity, which affects all organs including the healthy ones, and overall improvement in the disease treatment, which can be unnoticeable or minimal. Silver nanoparticles have been increasingly investigated due to their peculiar physical, chemical, and optical properties, which allows them to cover several applications, namely in the transport of drugs to a specific target in the body. Given the limitations of conventional cancer chemotherapy, which include low bioavailability and the consequent use of high doses that cause adverse effects, strategies that overcome these difficulties are extremely important. This review embraces an overview and presentation about silver nanoparticles used as anticancer drug carrier systems and focuses a discussion on the state of the art of silver nanoparticles exploited for transport of anticancer drugs and their influence on antitumor effects.

Bioleaching for resource recovery from low-grade wastes like fly and bottom ashes from municipal incinerators: A SWOT analysis.

Bioleaching (or microbial leaching) is a biohydrometallurgical technology that can be applied for metal recovery from anthropogenic waste streams. In particular, fly ashes and bottom ashes of municipal solid waste incineration (MSWI) can be used as a target material for biomining. Globally, approximately 46 million tonnes of MSWI ashes are produced annually. Currently landfilled or used as aggregate, these contain large amounts of marketable metals, equivalent to low-grade ores. There is opportunity to recover critical materials as the circular economy demands, using mesophile, moderately thermophile, and extremophile microorganisms for bioleaching. A Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis was developed to assess the potential of this biotechnology to recover critical metals from MSWI wastes. Bioleaching has potential as a sustainable technology for resource recovery and enhanced waste management. However, stakeholders can only reap the full benefits of bioleaching by addressing both the technical engineering challenges and regulatory requirements needed to realise and integrated approach to resource use.

Circular economy and the matter of integrated resources.

A circular economy offers solutions for global sustainability challenges through the transition from the linear take-make-use-dispose economy to a better organisation of resources. However, realising a circular economy has ran into various biophysical constraints. Circular economy implementation is shaped by the Ellen MacArthur Foundation's butterfly diagram that depicts 'biological' and 'technical' flows as separate cycles, subsequently interpreted as organic materials circulating in open loop systems via the environment and inorganic materials circulating in closed loop systems within society. Conversely, in our view, resource flows often contain tightly bound combinations of organic and inorganic materials either due to their natural composition or due to their technical design. Building on this observation, a new diagram is proposed that broadens the scope of the circular economy to cover extractive sectors and the return of materials from anthropogenic use to natural reserves, thereby reshaping the conceptual space within which solutions such as effective zero-waste-residue technologies, business models, and policies can be developed for the optimal management of integrated resources from a whole-system perspective. The diagram offers a realistic outlook on the biophysical limitations of circularity and endeavours to inspire discussion that supports the transition towards a sustainable circular economy.

Constructed wetlands for steel slag leachate management: Partitioning of arsenic, chromium, and vanadium in waters, sediments, and plants.

Constructed wetlands can treat highly alkaline leachate resulting from the weathering of steel slag before reuse (e.g. as aggregate) or during disposal in repositories and legacy sites. This study aimed to assess how metal(loid)s soluble at high pH, such as arsenic (As), chromium (Cr), and vanadium (V) are removed in constructed wetlands and how they accumulate in the sediments and the plants (Phragmites australis, common reed). The results show that reedbeds were very effective at removing calcium (98%), aluminium (81%), barium (98%), chromium (90%), gallium (80%), nickel (98%), and zinc (98%), and lowering pH and alkalinity. No statistical difference was found for As and V between leachate influent and wetland samples, showing that these metal(loid)s were not efficiently removed. As, Cr, and V were significantly higher in the reedbed sediments than in a reference site. However, sediment concentrations are not at levels that would pose a concern regarding reuse for agricultural purposes (average values of 39 ±â€¯26 mg kg-1 for As, 108 ±â€¯15 mg kg-1 for Cr, and 231 ±â€¯34 mg kg-1 for V). Also, there is no significant uptake of metals by the aboveground portions of the reeds compared to reference conditions. Results show statistically significant enrichment in metal(loid)s in rhizomes and also a seasonal effect on the Cr concentrations. The data suggest minimal risk of oxyanion-forming element uptake and cycling in wetlands receiving alkaline steel slag.

Atmospheric CO2 Sequestration in Iron and Steel Slag: Consett, County Durham, United Kingdom.

Carbonate formation in waste from the steel industry could constitute a nontrivial proportion of the global requirements for removing carbon dioxide from the atmosphere at a potentially low cost. To utilize this potential, we examined atmospheric carbon dioxide sequestration in a >20 million ton legacy slag deposit in northern England, United Kingdom. Carbonates formed from the drainage water of the heap had stable carbon and oxygen isotope values between -12 and -25 ‰ and -5 and -18 ‰ for δ13C and δ18O, respectively, suggesting atmospheric carbon dioxide sequestration in high-pH solutions. From the analyses of solution saturation states, we estimate that between 280 and 2900 tons of CO2 have precipitated from the drainage waters. However, by combining a 37 year long data set of the drainage water chemistry with geospatial analysis, we estimate that <1% of the maximum carbon-capture potential of the deposit may have been realized. This implies that uncontrolled deposition of slag is insufficient to maximize carbon sequestration, and there may be considerable quantities of unreacted legacy deposits available for atmospheric carbon sequestration.

Recovery of Al, Cr and V from steel slag by bioleaching: Batch and column experiments.

Steel slag is a major by-product of the steel industry and a potential resource of technology critical elements. For this study, a basic oxygen furnace (BOF) steel slag was tested for bacterial leaching and recovery of aluminium (Al), chromium (Cr), and vanadium (V). Mixed acidophilic bacteria were adapted to the steel slag up to 5% (w/v). In the batch tests, Al, Cr, and V were bioleached significantly more from steel slag than in control treatments. No statistical difference was observed arising from the duration of the leaching (3 vs 6 d) in the batch tests. Al and Cr concentrations in the leachate were higher for the smaller particle size of the steel slag (<75 µm), but no difference was observed for V. In the column tests, no statistical difference was found for pH, Al, Cr and V between the live culture (one-step bioleaching) and the supernatant (two-step bioleaching). The results show that the culture supernatant can be effectively used in an upscaled industrial application for metal recovery. If bioleaching is used in the 170-250 million tonnes of steel slag produced per year globally, significant recoveries of metals (100% of Al, 84% of Cr and 8% of V) can be achieved, depending on the slag composition. The removal and recovery percentages of metals from the leachate with Amberlite®IRA-400 are relatively modest (<67% and <5%, respectively), due to the high concentration of competing ions (SO42-, PO43-) in the culture medium. Other ion exchange resins can be better suited for the leachate or methods such as selective precipitation could improve the performance of the resin. Further research is needed to minimise interference and maximise metal recovery.

Hydraulic and biotic impacts on neutralisation of high-pH waters.

The management of alkaline (pH11-12.5) leachate is an important issue associated with the conditioning, afteruse or disposal of steel slags. Passive in-gassing of atmospheric CO2 is a low cost option for reducing Ca(OH)2 alkalinity, as Ca(OH)2 is neutralised by carbonic acid to produce CaCO3. The relative effectiveness of such treatment can be affected by both the system geometry (i.e. stepped cascades versus settlement ponds) and biological colonization. Sterilized mesocosm experiments run over periods of 20days showed that, due to more water mixing and enhanced CO2 dissolution at the weirs, the cascade systems (pH11.2→9.6) are more effective than settlement ponds (pH11.2→11.0) for lowering leachate alkalinity in all the tested conditions. The presence of an active microbial biofilm resulted in significantly more pH reduction in ponds (pH11.2→9.5), but had a small impact on the cascade systems (pH11.2→9.4). The pH variation in biofilm colonized systems shows a diurnal cycle of 1 to 1.5pH units due to CO2 uptake and release associated with respiration and photosynthesis. The results demonstrate that, where gradient permits, aeration via stepped cascades are the best option for neutralisation of steel slag leachates, and where feasible, the development of biofilm communities can also help reduce alkalinity.

Removal and recovery of vanadium from alkaline steel slag leachates with anion exchange resins.

Leachable vanadium (V) from steel production residues poses a potential environmental hazard due to its mobility and toxicity under the highly alkaline pH conditions that characterise these leachates. This work aims to test the efficiency of anion exchange resins for vanadium removal and recovery from steel slag leachates at a representative average pH of 11.5. Kinetic studies were performed to understand the vanadium sorption process. The sorption kinetics were consistent with a pseudo-first order kinetic model. The isotherm data cannot differentiate between the Langmuir and Freundlich models. The maximum adsorption capacity (Langmuir value qmax) was 27 mg V g-1 resin. In column anion exchange, breakthrough was only 14% of the influent concentration after passing 90 L of steel slag leachate with 2 mg L-1 V through the column. When eluting the column 57-72% of vanadium was recovered from the resin with 2 M NaOH. Trials on the reuse of the anion exchange resin showed it could be reused 20 times without loss of efficacy, and on average 69% of V was recovered during regeneration. The results document for the first time the use of anion exchange resins to remove vanadium from steel slag leachate. As an environmental contaminant, removal of V from leachates may be an obligation for long-term management requirements of steel slag repositories. Vanadium removal coupled with the recovery can potentially be used to offset long-term legacy treatment costs.

Vanadium removal and recovery from bauxite residue leachates by ion exchange.

Bauxite residue is an important by-product of the alumina industry, and current management practices do not allow their full valorisation, especially with regard to the recovery of critical metals. This work aims to test the efficiency of ion exchange resins for vanadium (V) removal and recovery from bauxite residue leachates at alkaline pH (11.5 and 13). As an environmental pollutant, removal of V from leachates may be an obligation of bauxite residue disposal areas (BRDA) long-term management requirements. Vanadium removal from the leachate can be coupled with the recovery, and potentially can be used to offset long-term legacy treatment costs in legacy sites. Kinetics studies were performed to understand the adsorption process. The rate kinetics for the V adsorption was consistent with the pseudo-first-order kinetic model, with a higher adsorption rate for pH 11.5 (1.2 min-1). Adsorption isotherm data fitted better to Freundlich equations than to the Langmuir model. The maximum adsorption capacity (Langmuir value q max) was greatest for pH 13 (9.8 mg V g-1 resin). In column tests, breakthrough was reached at 70 bed volumes with the red mud leachate at pH 13, while no breakthrough was achieved with the effluent at pH 11.5. In regeneration, 42 and 76 % of V were eluted from the resin with 2 M NaOH from the red mud leachate at pH 13 and 11.5, respectively. Further optimization will be needed to upscale the treatment.

Electrokinetic delivery of persulfate to remediate PCBs polluted soils: Effect of different activation methods.

Persulfate-based in-situ chemical oxidation (ISCO) for the remediation of organic polluted soils has gained much interest in last decade. However, the transportation of persulfate in low-permeability soil is very low, which limits its efficiency in degrading soil pollutants. Additionally, the oxidation-reduction process of persulfate with organic contaminants takes place slowly, while, the reaction will be greatly accelerated by the production of more powerful radicals once it is activated. Electrokinetic remediation (EK) is a good way for transporting persulfate in low-permeability soil. In this study, different activation methods, using zero-valent iron, citric acid chelated Fe(2+), iron electrode, alkaline pH and peroxide, were evaluated to enhance the activity of persulfate delivered by EK. All the activators and the persulfate were added in the anolyte. The results indicated that zero-valent iron, alkaline, and peroxide enhanced the transportation of persulfate at the first stage of EK test, and the longest delivery distance reached sections S4 or S5 (near the cathode) on the 6th day. The addition of activators accelerated decomposition of persulfate, which resulted in the decreasing soil pH. The mass of persulfate delivered into the soil declined with the continuous decomposition of persulfate by activation. The removal efficiency of PCBs in soil followed the order of alkaline activation > peroxide activation > citric acid chelated Fe(2+) activation > zero-valent iron activation > without activation > iron electrode activation, and the values were 40.5%, 35.6%, 34.1%, 32.4%, 30.8% and 30.5%, respectively. The activation effect was highly dependent on the ratio of activator and persulfate.

Electroremediation of PCB contaminated soil combined with iron nanoparticles: Effect of the soil type.

Polychlorinated biphenyls (PCB) are carcinogenic and persistent organic pollutants that accumulate in soils and sediments. Currently, there is no cost-effective and sustainable remediation technology for these contaminants. In this work, a new combination of electrodialytic remediation and zero valent iron particles in a two-compartment cell is tested and compared to a more conventional combination of electrokinetic remediation and nZVI in a three-compartment cell. In the new two-compartment cell, the soil is suspended and stirred simultaneously with the addition of zero valent iron nanoparticles. Remediation experiments are made with two different historically PCB contaminated soils, which differ in both soil composition and contamination source. Soil 1 is a mix of soils with spills of transformer oils, while Soil 2 is a superficial soil from a decommissioned school where PCB were used as windows sealants. Saponin, a natural surfactant, was also tested to increase the PCB desorption from soils and enhance dechlorination. Remediation of Soil 1 (with highest pH, carbonate content, organic matter and PCB concentrations) obtained the maximum 83% and 60% PCB removal with the two-compartment and the three-compartment cell, respectively. The highest removal with Soil 2 were 58% and 45%, in the two-compartment and the three-compartment cell, respectively, in the experiments without direct current. The pH of the soil suspension in the two-compartment treatment appears to be a determining factor for the PCB dechlorination, and this cell allowed a uniform distribution of the nanoparticles in the soil, while there was iron accumulation in the injection reservoir in the three-compartment cell.

Treatment of a suspension of PCB contaminated soil using iron nanoparticles and electric current.

Contaminated soils and sediments with polychlorinated biphenyls (PCB) are an important environmental problem due to the persistence of these synthetic aromatic compounds and to the lack of a cost-effective and sustainable remediation technology. Recently, a new experimental setup has been proposed using electrodialytic remediation and iron nanoparticles. The current work compares the performance of this new setup (A) with conventional electrokinetics (setup B). An historically contaminated soil with an initial PCB concentration of 258 µg kg(-1) was treated during 5, 10, 20 and 45 d using different amounts of iron nanoparticles in both setups A and B. A PCB removal of 83% was obtained in setup A compared with 58% of setup B. Setup A also showed additional advantages, such as a higher PCB dechlorination, in a shorter time, with lower nZVI consumption, and with the use of half of the voltage gradient when compared with the traditional setup (B). Energy and nZVI costs for a full-scale reactor are estimated at 72 € for each cubic meter of PCB contaminated soil treated on-site, making this technology competitive when compared with average off-site incineration (885 € m(-3)) or landfilling (231 € m(-3)) cost in Europe and in the USA (327 USD m(-3)).

Development of paper-based color test-strip for drug detection in aquatic environment: Application to oxytetracycline.

The wide use of antibiotics in aquaculture has led to the emergence of resistant microbial species. It should be avoided/minimized by controlling the amount of drug employed in fish farming. For this purpose, the present work proposes test-strip papers aiming at the detection/semi-quantitative determination of organic drugs by visual comparison of color changes, in a similar analytical procedure to that of pH monitoring by universal pH paper. This is done by establishing suitable chemical changes upon cellulose, attributing the paper the ability to react with the organic drug and to produce a color change. Quantitative data is also enabled by taking a picture and applying a suitable mathematical treatment to the color coordinates given by the HSL system used by windows. As proof of concept, this approach was applied to oxytetracycline (OXY), one of the antibiotics frequently used in aquaculture. A bottom-up modification of paper was established, starting by the reaction of the glucose moieties on the paper with 3-triethoxysilylpropylamine (APTES). The so-formed amine layer allowed binding to a metal ion by coordination chemistry, while the metal ion reacted after with the drug to produce a colored compound. The most suitable metals to carry out such modification were selected by bulk studies, and the several stages of the paper modification were optimized to produce an intense color change against the concentration of the drug. The paper strips were applied to the analysis of spiked environmental water, allowing a quantitative determination for OXY concentrations as low as 30ng/mL. In general, this work provided a simple, method to screen and discriminate tetracycline drugs, in aquaculture, being a promising tool for local, quick and cheap monitoring of drugs.

Electrodialytic remediation of polychlorinated biphenyls contaminated soil with iron nanoparticles and two different surfactants.

Polychlorinated biphenyls (PCB) are persistent organic pollutants (POP) that strongly adsorb in soils and sediments. There is a need to develop new and cost-effective solutions for the remediation of PCB contaminated soils. The suspended electrodialytic remediation combined with zero valent iron nanoparticles (nZVI) could be a competitive alternative to the commonly adapted solutions of incineration or landfilling. Surfactants can enhance the PCB desorption, dechlorination, and the contaminated soil cleanup. In this work, two different surfactants (saponin and Tween 80) were tested to enhance PCB desorption and removal from a soil sampled at a polluted site, in a two-compartment cell where the soil was stirred in a slurry with 1% surfactant, 10mL of nZVI commercial suspension, and a voltage gradient of 1Vcm(-1). The highest PCB removal was obtained with saponin. Higher chlorinated PCB congeners (penta, hexa, hepta and octachlorobiphenyl) showed removal percentages between 9% and 96%, and the congeners with highest removal were PCB138, PCB153 and PCB180. The use of low level direct current enhanced PCB removal, especially with saponin. Electrodechlorination of PCB with surfactants and nZVI showed encouraging tendencies and a base is thus formed for further optimization towards a new method for remediation of PCB polluted soils.