Potential Remediation Technology Research Articles

Mediated Peroxymonosulfate Activation at the Single Atom Fe-N3O1 Sites: Synergistic Degradation of Antibiotics by Two Non-Radical Pathways.

The activation of persulfates to degrade refractory organic pollutants is a hot issue in advanced oxidation right now. Here, it is reported that single-atom Fe-incorporated carbon nitride (Fe-CN-650) can effectively activate peroxymonosulfate (PMS) for sulfamethoxazole (SMX) removal. Through some characterization techniques and DFT calculation, it is proved that Fe single atoms in Fe-CN-650 exist mainly in the form of Fe-N3O1 coordination, and Fe-N3O1 exhibited better affinity for PMS than the traditional Fe-N4 structure. The degradation rate constant of SMX in the Fe-CN-650/PMS system reached 0.472min-1, and 90.80% of SMX can still be effectively degraded within 10min after five consecutive recovery cycles. The radical quenching experiment and electrochemical analysis confirm that the pollutants are mainly degraded by two non-radical pathways through 1O2 and Fe(IV)═O induced at the Fe-N3O1 sites. In addition, the intermediate products of SMX degradation in the Fe-CN-650/PMS system show toxicity attenuation or non-toxicity. This study offers valuable insights into the design of carbon-based single-atom catalysts and provides a potential remediation technology for the optimum activation of PMS to disintegrate organic pollutants.

Bioavailability enhancement of petroleum-contaminated soil by electrokinetic remediation

The Electro kinetic Remediation Technology (EKR) is recognized as the most potential remediation technology for soils with low permeability, like clay soil characteristics. Electrokinetic treatment could increase the bioavailability of contaminants in bioremediation petroleum-contaminated soil. The study, “Bioavailability enhancement of petroleum contaminated soil by electrokinetic remediation,” is experimental research in a laboratory to improve the bioavailability of petroleum hydrocarbons on clay during bioremediation with initial treatment using electrokinetic remediation techniques, finding optimum electrokinetic operating conditions of remediations, and analyzing the mechanism of remediation process in contaminated soil. Bioavailability enhancement was studied for 35 days. Polluted soil was treated with an electrokinetic box test (17cm×12cm×10cm), and DC power was used for 48 hours. Total Petroleum Hydrocarbon (TPH) concentration was determined by gravimetric methods. The results showed that the characteristics of the soil samples were dominated by 49.31% clay. The initial concentration of TPH in polluted soil is 3.7%. The electrokinetic applications during 48 hours and followed by bioremediation for 35 days those processes removed TPH up to 80.74 % (from 33780.66 mg HC (kg dry w)-1 to 6506.155176 mg HC (kg dry w)-1. There is an increase in bioavailability indicated by the rise in bacterial populations and an increase in biodegradation after electrokinetic remediation. With this approach, bioavailability has been increased by 70.18%. Bio-electrokinetic remediation is the recommended method for polluted clay soils with low bioavailability.

Phycoremediation and simultaneous production of protein‐rich algal biomass from aquaculture and agriculture wastewaters

AbstractBACKGROUNDMicroalgae cultivation in wastewaters is a potential remediation technology for converting residual nutrients into valuable biomass for biofuels, fertilizers, animal and aquaculture feeds, and bio‐based chemicals. The objective of this study was to determine the potential for microalgae phycoremediation of aquaculture and agriculture wastewaters for sustainable production of nutrient‐rich algal biomass.RESULTSThirty‐seven aquaculture and agriculture wastewaters were evaluated as growth media for two freshwater, chlorophytic microalgae strains (Chlorella sorokiniana SMC14M and Scenedesmus sp. AMDD). Although nutrient levels and physicochemical parameters of the wastewaters varied widely, phycoremediation efficiency of nitrogen and phosphorous was high (> 70%) for a large majority of them, with both microalgae strains. Photobioreactor cultivation (300 L) of C. sorokiniana grown on finfish aquaculture wastewater (CA2) and standard growth medium (SGM) exhibited similar biomass production levels and nutritional compositions of moisture (4.9–5.0%), ash (5.9–6.1%), nitrogen (8.6–8.8%), protein (41.0–42.1%), lipid (8.6–8.8%), carbohydrate (38.3–39.3%) and gross energy (22.2–22.3 MJ⋅kg−1) with highly similar fatty acid and amino acid profiles.CONCLUSIONSThis study demonstrates that the use of freshwater microalgae to remediate various aquaculture and agriculture wastewaters, while producing valuable nutrient‐rich biomass, is feasible. We have found that a particular finfish aquaculture wastewater (CA2) contains all of the nutrients required for rapid microalgae growth, avoiding the need for expensive commercial fertilizers. The biochemical composition of C. sorokiniana grown on CA2 aquaculture wastewater has good potential for use as a nutrient‐rich ingredient for animal and aquaculture feeds, fertilizers products, biofuels and other applications, resulting in remediated water that could be reused. © 2023 National Research Council Canada. Reproduced with the permission of the Minister of Innovation, Science, and Economic Development.

Efficient remediation of the field soil contaminated with PAHs by amorphous porous iron material activated peroxymonosulfate

An amorphous porous iron material (FH) was firstly self-synthesized using a simple coprecipitation approach and then utilized to activate peroxymonosulfate (PMS) for the catalytic degradation of pyrene and remediation of PAHs contaminated soil on site. FH exhibited more excellent catalytic activity than traditional hydroxy ferric oxide and possessed stability at a pH range of 3.0–11.0. According to quenching studies and electron paramagnetic resonance (EPR) analyses, non-radicals (Fe(IV) = O and 1O2) were the major reactive oxygen species (ROS) in the FH/PMS system's degradation of pyrene. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) of FH before and after the catalytic reaction, as well as active site substitution experiments and electrochemical analysis all verified that PMS adsorbed on FH could produce more abundant bonded hydroxyl groups (Fe–OH) which dominated the radical and non-radical oxidation reactions. Then, a possible pathway for pyrene degradation was presented according to gas chromatography-mass spectrometry (GC–MS). Furthermore, the FH/PMS system exhibited excellent catalytic degradation in the remediation of PAH-contaminated soil at real sites. This work provides a remarkable potential remediation technology of persistent organic pollutants (POPs) in environmental and will contribute to understanding the mechanism of Fe-based hydroxides in advanced oxidation processes.

Remediation mechanism of Cu, Zn, As, Cd, and Pb contaminated soil by biochar-supported nanoscale zero-valent iron and its impact on soil enzyme activity

Recently, heavy metal contaminated soil has been widespread concerned. Herein, rice straw-derived biochar-supported nanoscale zero-valent iron (nZVI@BC) composite was prepared and characterized, and its remediation performance in Cu, Zn, As, Cd, and Pb contaminated soil were evaluated. nZVI@BC demonstrated better immobilization effect on multiple heavy metals than biochar, and the residual component of Cu, Zn, As, Cd, and Pb increased by 10.27%, 7.18%, 7.44%, 9.26%, and 12.75%, respectively. After nZVI@BC treatment, the soil pH, the available iron, cation exchange capacity, total organic carbon, and dissolved organic carbon increased. Besides, soil enzyme (catalase, urease, and fluorescein diacetate hydrolase) activities significantly increased, especially, the catalase activity was doubled. Furthermore, the immobilization mechanism was explored, including surface adsorption, electrostatic attraction, ion exchange, coprecipitation, oxidation-reduction, and complexation. Additionally, the adsorption sites of Pb and Cu were more competitive, and As synergistically promoted the adsorption of Pb, forming a ternary surface complex PbFeAsO4OH. Therefore, it well demonstrates that nZVI@BC may be a potential technology for remediation of multiple heavy metals contaminated soil.

Impact of microbial-rock-CO2 interactions on containment and storage security of supercritical CO2 in carbonates

Carbon Capture and Sequestration (CCS) has been widely adopted as a key technology to mitigate anthropogenic greenhouse gas emissions and to meet the 2050 net-zero carbon emission target. However, the long-term CO2 storage security and potential leakage in geologic formations still pose a major concern to the commercial implementation and viability of CCS as an efficient and safe carbon-negative technology against climate change. Also, the long-term effectiveness of carbonate formations for carbon sequestration is poorly constrained due to the reactivity of carbonates with pore water when exposed to CO2, the possible leakage paths that might develop, and potential consequences that could occur. Here, we examine CO2 storage in carbonate formations and the possible leakage issues and explore a potential remediation technology for improving storage security in carbonate formations to mitigate CO2 leakage and achieve long-term containment. In this study, samples from deep carbonate intervals are treated with cultured microbial media and/or supercritical CO2 (ScCO2). These treatments are complemented with pre- and post-treatment geomechanical tests, permeability measurements, Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD) analyses to assess mechanical, chemical, and microstructural responses of carbonates exposed to ScCO2 in the presence or absence of microbial media in the pore volume. The results indicate that, in the absence of sufficient post-injection remediation, the long-term integrity of CO2 storage in carbonate reservoirs may be compromised by CO2 leakage leading to environmental degradation. However, analyses of results suggest that coupling microbial treatment with CCS in carbonate reservoirs can potentially maintain long-term CO2 storage security by moderately enhancing its mechanical strength and integrity. In tight carbonate samples, unconfined compressive strength is shown to increase +85% with Poisson's ratio decreasing by 32% and fracture toughness increasing +108%. In more porous carbonate samples, unconfined compressive strength increases +64%, Poisson's ratio decreases by 34%, and fracture toughness increases +130%, all relative to the same CO2 saturation in carbonates without microbial media. Further, results show a post-microbial-CO2 change in permeability, dissolution and reprecipitation of stronger minerals due to microstructural alteration and occlusion of leakage pathways. This study provides new insights into the viability of CCS in carbonate reservoirs with microbial treatment as an efficient technology against climate change and greenhouse gas emissions to prevent leakage of stored CO2 and provide adequate long-term CO2 storage retention.

Phytoremediation prospects of per- and polyfluoroalkyl substances: A review

Extensive use of per- and polyfluoroalkyl substances (PFASs) in various industrial activities and daily-life products has made them ubiquitous contaminants in soil and water. PFAS-contaminated soil acts as a long-term source of pollution to the adjacent surface water bodies, groundwater, soil microorganisms, and soil invertebrates. While several remediation strategies exist to eliminate PFASs from the soil, strong ionic interactions between charged groups on PFAS with soil constituents rendered these PFAS remediation technologies ineffective. Pilot and field-scale data from recent studies have shown a great potential of PFAS to bio-accumulate and distribute within plant compartments suggesting that phytoremediation could be a potential remediation technology to clean up PFAS contaminated soils. Even though several studies have been performed on the uptake and translocation of PFAS by different plant species, most of these studies are limited to agricultural crops and fruit species. In this review, the role of both aquatic and terrestrial plants in the phytoremediation of PFAS was discussed highlighting different mechanisms underlying the uptake of PFASs in the soil–plant and water-plant systems. This review further summarized a wide range of factors that influence the bioaccumulation and translocation of PFASs within plant compartments including both structural properties of PFASs and physiological properties of plant species. Even though phytoremediation appears to be a promising remediation technique, some limitations that reduced the feasibility of phytoremediation in the practical application have been emphasized in previous studies. Additional research directions are suggested, including advanced genetic engineering techniques and endophyte-assisted phytoremediation to upgrade the phytoremediation potential of plants for the successful removal of PFASs.

Effect of mono- and di-valent cations on PFAS removal from water using foam fractionation – A modelling and experimental study

Per- and poly-fluoroalkyl substances (PFAS) are a group of recalcitrant compounds whose widespread use in a variety of consumer products has led to contamination of groundwater and surface water systems. Foam fractionation is a potential remediation technology for treatment of PFAS contaminated water, which takes advantage of the high surface activity imparted by the fluorocarbon chain to remove them from solution by adsorption to the surface of air bubbles. In this study, the effect of mono- and di-valent cations on the performance of a PFAS foam fractionation process where sodium dodecyl sulphate (SDS) is used as a co-foaming agent has been evaluated. The results indicated that the separation of PFAS was improved in an order that followed the charge density of the salts with Mg2+ > Na+ > K+. It was also observed that at salt concentrations above 100 mM for Na+, above 10 mM for K+ and Mg2+ but between 0.1 and 10 mM for Ca2+ in the presence of greater than 4 ppm of SDS, the cations can complex with the SDS in the system and suppress foam formation due to the surfactant precipitation. Foam fractionation was able to remove perfluorohexane sulphonic acid (PFHxS), perfluorooctanoic acid (PFOA) and perfluorooctane sulphonic acid (PFOS) from a sample of Australian groundwater to below the analytical detection limit of 0.1 ppb within 60 min with SDS being used as the co-foaming agent, but was unable to remove the short chain perfluorobutanoic acid (PFBA).

Oryza sativa as a Tool for Assessing Arsenic Efficacy of Arsenic Remediation of Agricultural Soils by Sulfidated Zerovalent Iron Nanoparticles.

Arsenic (As) is highly toxic in its inorganic form. It is naturally presented at elevated levels in the groundwater of a number of countries and contaminates drinking water sources, generating numerous health and environmental problems. Current methodologies for its remediation have deficiencies which fuel the constant exploration of new alternatives. Therefore, the development of robust methodologies for the evaluation of potential remediation technologies are not only timely but also highly needed. In this study we have investigated the use of a rice plant species as a means to evaluate the efficacy of As remediation using sulfidated zerovalent iron nanoparticles (S-nZVI). The obtained results show that addition of S-nZVI to soils had a beneficial impact to plant growth in the presence of As(V) and As(III) concentrations between 10 and 50 ppm. Positive effects were also found for plant biomass and chlorophyll content in the plants. Moreover, evaluation of As uptake by plants showed that the application of S-nZVI reduced the amount of both As(V) and As(III) in shoots and increased the amount of As in the roots. Studies on the Fe and P content in shoot and root after exposure to As with and without the nanoparticles demonstrated that nanoparticles remain mainly in the roots and that P uptake by plants was not significantly affected, suggesting that S-nZVI treatment is safe for plants at the assayed doses. These results overall confirm the method as robust and reliable for demonstrating the reduction of the bioavailability of As in soil by S-nZVI sequestration.

Rapid reactivation of aged NZVI/GO by Shewanella CN32 for efficient removal of tetrabromobisphenol A and associated reaction mechanisms

Tetrabromobisphenol A (TBBPA) is one of the most widely applied brominated flame retardants, which has consequently resulted in severe environmental contamination. Graphene oxide-loaded nanoscale zero-valent iron (NZVI/GO) has previously shown excellent performance for potential TBBPA removal. However, the aging of NZVI/GO resulted in reduced reaction rates. In this study, Shewanella CN32 was used to reactivate the performance of aged NZVI/GO. The results demonstrated that CN32 significantly reactivated aged NZVI/GO (27%) and consequently improved the removal of TBBPA by 240% in aged NZVI/GO+CN32 (92%). Compared to aged NZVI (0.07 mM), CN32 rapidly decomposed the iron oxide passivation layer of aged NZVI/GO, with a subsequent increase in the release of Fe2+ ions (0.12 mM). Moreover, Fe(II) vivianite (FeII3(PO4)2·8H2O) and SO42− type green rust (Fe3.6Fe0.9(O,OH,SO4)9) formed at the surface of aged NZVI/GO+CN32. GO accelerated the reduction of dissimilatory iron (α-Fe2O3) and the formation of vivianite crystals. Vivianite further improved the debromination of TBBPA. Furthermore, the semiquinone radicals (C=O) in the interface of the aged NZVI/GO effectively mediated electron transfer and reactivated the performance of aged NZVI/GO by CN32. It could therefore be concluded that CN32-induced iron oxide reduction and NZVI exposure, C=O mediated electron transfer, and vivianite-induced debromination were the main removal mechanisms of TBBPA in the system. It is a potential technology for convenient remediation of soil, groundwater, and lake.

Nitrate Removal Performance of Denitrifying Woodchip Bioreactors in Tropical Climates

In Australia, declining water quality in the Great Barrier Reef (GBR) is a threat to its marine ecosystems and nitrate (NO3−) from sugar cane-dominated agricultural areas in the coastal catchments of North Queensland is a key pollutant of concern. Woodchip bioreactors have been identified as a potential low-cost remediation technology to reduce the NO3− runoff from sugar cane farms. This study aimed to trial different designs of bioreactors (denitrification walls and beds) to quantify their NO3− removal performance in the distinct tropical climates and hydrological regimes that characterize sugarcane farms in North Queensland. One denitrification wall and two denitrification beds were installed to treat groundwater and subsurface tile-drainage water in wet tropics catchments, where sugar cane farming relies only on rainfall for crop growth. Two denitrification beds were installed in the dry tropics to assess their performance in treating irrigation tailwater from sugarcane. All trialled bioreactors were effective at removing NO3−, with the beds exhibiting a higher NO3− removal rate (NRR, from 2.5 to 7.1 g N m−3 d−1) compared to the wall (0.15 g N m−3 d−1). The NRR depended on the influent NO3− concentration, as low influent concentrations triggered NO3− limitation. The highest NRR was observed in a bed installed in the dry tropics, with relatively high and consistent NO3− influent concentrations due to the use of groundwater, with elevated NO3−, for irrigation. This study demonstrates that bioreactors can be a useful edge-of-field technology for reducing NO3− in runoff to the GBR, when sited and designed to maximise NO3− removal performance.

Carbothermal reduction synthesis of zero-valent iron and its application as a persulfate activator for ciprofloxacin degradation

• Novel Fe@BC was synthesized by carbothermal reduction method. • Corn straw based-biochar was used as a carbon source to prepare ZVI. • The synthesis process of ZVI was the conversion of Fe 2 O 3 into Fe 3 O 4 , and then into Fe 0 . • Ciprofloxacin was effectively removed by Fe@BC/PS. In the present research, zero-valent iron (ZVI) was synthesized by carbothermal reduction method and its formation mechanism was studied. The obtained material (Fe@BC) was applied as a persulfate (PS) catalyst for ciprofloxacin degradation. Further, Scanning Electron Microscopy (SEM) of Fe@BC has shown that the crystal shape of Fe 2 O 3 changed with the increase in temperature, and also revealed the spherical morphology of ZVI. X-ray Diffraction (XRD) further verified the process of conversion of Fe 2 O 3 to Fe 3 O 4 and then to ZVI. X-ray Photoelectron Spectroscopy (XPS) revealed that the change of iron valence state during the conversion process and the peak area of Fe 2+ increased with sintering temperature. The effect of experimental parameters including pH, Fe@BC dosage, PS concentration and temperature on ciprofloxacin degradation, were thoroughly investigated. The results illustrated that the Fe@BC has excellent catalytic performance and can remove 90.78% of ciprofloxacin within 120 min. Free radical quenching experiments confirmed that the reaction of ciprofloxacin with ∙ OH and SO 4 ∙ - mainly occurs on the Fe@BC surface. Based on the different experiments, it was proposed that degradation mechanism of ciprofloxacin via Fe@BC includes three aspects. Thus, it was found that carbothermal synthesis of Fe@BC is cost effective and potential technology for ciprofloxacin remediation.

Microplastics in marine environment: a review on sources, classification, and potential remediation by membrane technology

Microplastics are pollutants highly stable to complete biodegradation and require more specific separation processes for their removal. Classification and potential remediation technologies, such as membrane technology, are discussed in this review.

Sulfadiazine removal using green zero-valent iron nanoparticles: A low-cost and eco-friendly alternative technology for water remediation

In this work, the effectiveness of green zero-valent iron nanoparticles (gnZVIs) for the removal of the antibiotic sulfadiazine (SDZ) from water via adsorption and reduction was tested. Additionally, the effectiveness of this material as a catalyst for the Fenton and photo-Fenton processes was also investigated. This represents the first study concerning the use of gnZVIs for the degradation of a sulfonamide antibiotic. The results obtained indicate that gnZVIs were able to remove up to 58% of SDZ via adsorption and up to 69% via adsorption plus reduction using a SDZ/Fe3+ molar ratio of 1:61.6. Furthermore, gnZVIs showed strong effectiveness as a catalyst for the Fenton and photo-Fenton reactions, with complete SDZ removal in 8 h and 5 min, respectively, using a SDZ/Fe3+/H2O2 molar ratio of 1:38.4:38.4. These results demonstrate that the use of gnZVIs constitutes an attractive and potential alternative technology for water remediation, reducing environmental impact and operational costs.

Dechlorination and defluorination capability of sulfidized nanoscale zerovalent iron with suppressed water reactivity

Recently, sulfidation of nanoscale zerovalent iron (S-nZVI) has become a potential remediation technology. However, the impact of sulfidation methods and actual sulfur content ([S/Fe]particle) on the physicochemical properties and the reactivity of S-nZVI remains unknown. Here, we synthesized S-nZVI via one co-sulfidation and three post-sulfidation methods to determine how different sulfur reagents and addition procedures affect the reactivity of S-nZVI for defluorination. The measured S amounts of co-sulfidized S-nZVI and post-sulfidized S-nZVI was much lower than their dose. Different sulfur reagents and sulfidation approach would affect the amount and speciation of sulfur in the particles. Sulfidation of nZVI improved the reactivity for dechlorination (up to 12-fold) and defluorination (up to 3-fold) of florfenicol (FF), but inhibited the reactivity with water (up to 31-fold). Density functional theory calculations showed that sulfidation increases the hydrophobicity of materials, and the amount and nature of sulfur affect the hydrophobicity and the number of blocked H sites. S-nZVI particles with more S2− and S22− species showed faster dechlorination and defluorination of FF. Up to ~ 45% of FF was defluorinated by S-nZVI after 15 days reaction at room temperature and pressure. The [S/Fe]particle and Fe0 content was responsible for the initial and long-term defluorination, respectively. These results suggest that S-nZVI could be a promising agent for defluorination, and the sulfur reagents and sulfidation approach would affect its properties and reactivity.

Potential of Vetiver grass for the phytoremediation of a real multi-contaminated soil, assisted by electrokinetic.

Phytoremediation assisted by electrokinetic is a potential technology for remediation of contaminated soil, but little is known about its application on real contaminated soils. This study aims to evaluate the Vetiver grass application on the electro-phytoremediation of a real contaminated soil around a metal smelter factory. Different types of the electric field (AC-DC), voltage gradient (1-2V/cm), saturation and unsaturation condition, and Eh-pH variation were investigated for Vetiver electro-phytoremediation performance. Vetiver grass had been grown for 21 days. Then three different voltage gradients (1, 2DCV/cm and 2ACV/cm) were applied for 8h/d across the soil domain for the next 21 days in comparison with a control cell without electric field (PR). The results showed that despite the AC current application which induced small changes, the application of DC current significantly changed the Eh-pH values. The maximum accumulation of extractable metals in Vetiver grass occurred in 2DCV/cm that shows approximately 50% increase in comparison with the AC and PR cells. The presence of contaminants poisons the Vetiver in all cells and all plants under 2DCV/cm dried out at the end of the experiment. Despite the significant reduction of heavy metals, there was no noticeable phytoextraction due to the application of DC current. Therefore, DC current can be used for phytoremediation through phytostabilization. However, the overall metals uptake in plants shoots under AC treatment with BCF>1 was much higher than the PR and DC treatment. Considering the translocation rate and plants health, if the AC current is applied in a long treatment time, it could have better results in electro-phytoremediation of the Vetiver grass through phytoextraction process. However, the maximum removal of heavy metals was in the cathode part of the cell under 2DCV/cm that shows 65% improvement in comparison with the PR cell.

Kinetics and mechanisms of debromination of tetrabromobisphenol A by Cu coated nano zerovalent iron

Brominated flame retardants are of concern to our environment because of its endocrine disruptive, immune toxicant characteristics, and toxic brominated byproducts. As a potential remediation technology, debromination of tetrabromobisphenol A (TBBPA) from both aqua and soil by Cu coated nano zero-valent iron particles (Cu-nZVI) was investigated. Because of its catalytic reductive properties, Cu-nZVI has a potential for removing TBBPA. Batch experiments show that Cu-nZVI effectively debrominated TBBPA into tri-, di-, mono-bromobisphenol A, and bisphenol A (BPA) with a low suspension density (0.5 g L−1). As indicated by the low apparent activation energy (69.66 kJ mol−1), the optimal reaction condition was the Cu loading of 0.5 wt%, 27 °C and pH 5.0. Tetrabromobisphenol A (10 mg L−1) was transformed into several reaction products within 120 min, and BPA was detected as a major reaction product after 240 min. The reaction rate constant (kobs) was proportionally correlated to solid-solution ratio and temperature. The concentration of metals during the debromination was too low (less than 0.13 mg L−1) to induce an adverse effect on the ecosystem. During the redox reaction, a new mineral, magnetite formed on particles’ surface accompanied by the oxidation of Fe0 and the elevation of pH. This study suggests that Cu-nZVI has the potential to be explored for the rapid and complete debromination of brominated flame retardants in both aquatic and edaphic environments.

Potential Electrokinetic Remediation Technologies of Laboratory Scale into Field Application- Methodology Overview

Heavy metal in soil possesses high contribution towards soil contamination which causes to unbalance ecosystem. There are many ways and procedures to make the electrokinetic remediation (EKR) method to be efficient, effective, and potential as a low cost soil treatment. Electrode compartment for electrolyte is expected to treat the contaminated soil through electromigration and enhance metal ions movement. The electrokinetic is applicable for many approaches such as electrokinetic remediation (EKR), electrokinetic stabilization (EKS), electrokinetic bioremediation and many more. This paper presents a critical review on comparison of laboratory scale between EKR, EKS and EK bioremediation treatment by removing the heavy metal contaminants. It is expected to propose one framework of contaminated soil mapping. Electrical Resistivity Method (ERM) is one of famous indirect geophysical tools for surface mapping and subsurface profiling. Hence, ERM is used to mapping the migration of heavy metal ions by electrokinetic.

Historical record, source, and toxicity assessment of sedimentary organic matter using molecular composition of hydrocarbons in an urban lake, Wuhan, China

The historical record of the spatial distribution, source, occurrence, and ecotoxicology of organic matter deposited in the past 100 years was investigated in a sediment core from an urban lake, in central China by analyzing different organic targets. These targets included total organic carbon (TOC), n-alkanes, representative petroleum biomarkers of terpanes and steranes, non-alkylated polycyclic aromatic hydrocarbons (PAHs), and their alkylated congeners (APAHs). Three sediment cores were collected from East Lake (Wuhan, China) in September 2013. The freeze-dried samples were Soxhlet extracted and cleaned up/fractionated into saturated and aromatic fractions. Gas chromatography equipped with mass spectrometry (GC-MS) was used to analyze the specific target groups. The TOC content of sediment was determined by an elemental analyzer after the freeze-dried sediments were pre-treated with 1 mol L−1 HCl to remove carbonate. The impact of human activities has become more serious since the 1960s as determined by analyzing the historical records of the measured parameters, due to the isolation of the study water body from the Yangtze River and the development of the local social economy. Higher plant wax was the major source of the identified n-alkanes; non-alkylated PAHs were more abundant than their alkylated congeners over the past 100 years. The source identification of n-alkanes, petroleum biomarkers, and PAHs suggested that the mixed sources, including biogenic and petrogenic input, and the incomplete combustion of biomass/solid fossil fuel have contributed to the organic matter in the study lake. The toxicity assessment suggested the presence of PAHs would not cause potential toxicity to the benthic organisms. The historical record of organic matter with different molecular compositions reflects the hydrodynamic condition of the study lake and the development of the local social economy. The mixed biogenic, pyrogenic, and petrogenic sources have contributed to the lake sediments. The detected PAHs did not have negative impacts to benthic organics. This study will provide valuable information to control organic contamination and guide potential remediation technologies in the future.

Removal of industrial dyes and heavy metals by Beauveria bassiana: FTIR, SEM, TEM and AFM investigations with Pb(II).

Presence of industrial dyes and heavy metal as a contaminant in environment poses a great risk to human health. In order to develop a potential technology for remediation of dyes (Reactive remazol red, Yellow 3RS, Indanthrene blue and Vat novatic grey) and heavy metal [Cu(II), Ni(II), Cd(II), Zn(II), Cr(VI) and Pb(II)] contamination, present study was performed with entomopathogenic fungi, Beauveria bassiana (MTCC no. 4580). High dye removal (88-97%) was observed during the growth of B. bassiana while removal percentage for heavy metals ranged from 58 to 75%. Further, detailed investigations were performed with Pb(II) in terms of growth kinetics, effect of process parameters and mechanism of removal. Growth rate decreased from 0.118h-1 (control) to 0.031h-1, showing 28% reduction in biomass at 30mgL-1 Pb(II) with 58.4% metal removal. Maximum Pb(II) removal was observed at 30°C, neutral pH and 30mgL-1 initial metal concentration. FTIR analysis indicated the changes induced by Pb(II) in functional groups on biomass surface. Further, microscopic analysis (SEM and atomic force microscopy (AFM)) was performed to understand the changes in cell surface morphology of the fungal cell. SEM micrograph showed a clear deformation of fungal hyphae, whereas AFM studies proved the increase in surface roughness (RSM) in comparison to control cell. Homogenous bioaccumulation of Pb(II) inside the fungal cell was clearly depicted by TEM-high-angle annular dark field coupled with EDX. Present study provides an insight into the mechanism of Pb(II) bioremediation and strengthens the significance of using entomopathogenic fungus such as B. bassiana for metal and dye removal.