Search

Ethylenediamine-N,N'-disuccinic acid (EDDS) has been studied extensively for its potential use as an amendment in agriculture due to its numerous beneficial properties. The widespread usage of microplastics (MPs) poses a growing threat to plant growth. This study investigated the effects of Polystyrene MPs (PSMPs) and EDDS on soil pH, EC, organic matter (OM), available nutrients, and maize (Zea mays L.) growth in a calcareous soil. Results showed that both PS and EDDS had significant effects on soil pH, with higher concentrations leading to a decrease in pH. PSMPs negatively impacted soil health by increasing EC and decreasing OM, nitrogen (N), phosphorus (P), and potassium (K). EDDS had potential applications in soil remediation and phytoremediation by decreasing EC and increasing N, P, and K. The interaction between EDDS and PSMPs suggests that their effects on soil pH may be modulated by each other. The study highlights the potential negative impacts of high concentrations of PS on soil health and the potential benefits of using EDDS at lower concentrations in soil remediation and phytoremediation. However, further research is needed to understand the mechanisms and environmental impacts of EDDS and the combined effects of EDDS and PSMPs on soil properties and plant growth. Plastic pollution is a serious environmental issue affecting soil health worldwide, and this study sheds new light on the potential benefits of using EDDS at lower concentrations for soil remediation and phytoremediation. The findings reveal that EDDS can mitigate the negative impacts of PS on soil health and maize growth by improving nutrient availability, enhancing soil structure, and water retention. The study is the first to investigate the interactive effects of EDDS and PS on maize growth parameters across different levels of PS contamination. The results provide critical insights into the mechanisms underlying the mitigating effects of EDDS and highlight the need for further research on the environmental impacts of plastic pollution and effective management practices. Overall, this study presents a novel approach to mitigating the negative impacts of plastic pollution on soil health and crop production, with important implications for sustainable agriculture and environmental preservation. This study shows that EDDS, at lower concentrations, can mitigate the negative impacts of PSMPS on soil health and maize growth. It is the first to examine interactions between EDDS and PSMPS across varying levels of contamination. The results point to the potential benefits of EDDS as a soil amendment to remediate MPs pollution, revealing insights into its mechanisms of action. Findings suggest possible solutions for MPs pollution in agriculture but call for more research to balance environmental goals. Both EDDS and PSMPs impacted soil pH, EC, OM, and nutrient levels. PSMPS caused pH decrease, increased EC, and reduced OM, N, P, and K levels, negatively affecting soil health. EDDS showed potential for soil remediation, increasing N, P, and K levels, and decreasing EC, with optimal concentrations. Interaction between EDDS and PSMPs influenced soil pH modulation, revealing interplay between their effects. PSMPs had significantly negative effects on maize growth parameters, including root and shoot dry weight, chlorophyll content, leaf area, and plant height. EDDS amendment mitigated PSMPs's adverse impacts on maize growth, especially chlorophyll content and leaf area. Interaction between PSMPs and EDDS improved soil and plant health, possibly via chelation, property alteration, and enhanced nutrient availability. EDDS demonstrates promise as an environmentally friendly strategy to counteract the effects of PSMPs contamination on agricultural soils and crop productivity. Further research is essential to understand EDDS mechanisms and environmental impacts, as well as the combined effects of EDDS and PSMPs on soil and plant properties. [ABSTRACT FROM AUTHOR]

The superabsorbents' application as materials for the preparation of modern mineral fertilizers of controlled activity is presented. Under the static conditions, the commercial acrylic-based Agro® Hydrogel was used as a sorbent for Cu(II), Fe(III), Mn(II), and Zn(II) ions in the presence of three biodegradable complexing agents of the new generation: (N-1,2-dicarboxyethyl)-D,L-aspartate acid (IDHA), N,N-ethylenediaminedisuccinic acid (EDDS) and N,N-bis(carboxymethyl) glutamic acid (GLDA). The ions and complexes concentrations were determined by the inductively coupled plasma optical emission spectrometer (ICP-OES). The characterization of hydrogel before and after the adsorption process was made using the Fourier transform infrared spectroscopy (FT-IR), surface area determination (ASAP), scanning electron microscopy (SEM-EDS) as well as the thermogravimetric (TGA) methods. The influence of the phase contact time, initial concentration, and pH on the adsorption capacities was investigated. The kinetic and adsorption parameters were determined. The Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin adsorption models were applied to describe the experimental data. The Langmuir isotherm model accurately characterized the equilibrium process. The adsorption process was fast, and it reached equilibrium after 60 min of the phase contact time. The research on the adsorption of Cu(II), Fe(III), Mn(II), and Zn(II) onto Agro® Hydrogel with IDHA, EDDS, and GLDA indicates that these complexing agents improve process efficiency. [ABSTRACT FROM AUTHOR]

The ability of plants to accumulate heavy metals is a crucial factor in phytoremediation. This study investigated the effect of NaCl and S,S-ethylenediaminesuccinic acid (EDDS) on heavy metal accumulation in Kosteletzkya pentacarpos in soil polluted with arsenic, cadmium, lead, and zinc. The addition of NaCl reduced the bioavailability of arsenic and cadmium, while EDDS increased the bioavailability of arsenic and zinc. The toxicity of the polymetallic pollutants inhibited plant growth and reproduction, but NaCl and EDDS had no significant positive effects. NaCl reduced the accumulation of all heavy metals in the roots, except for arsenic. In contrast, EDDS increased the accumulation of all heavy metals. NaCl reduced the accumulation of arsenic in both the main stem (MS) and lateral branch (LB), along with a decrease in cadmium in the leaves of the main stem (LMS) and zinc in the leaves of the lateral branch (LLB). Conversely, EDDS increased the accumulation of all four heavy metals in the LB, along with an increase in arsenic and cadmium in the LMS and LLB. Salinity significantly decreased the bioaccumulation factor (BF) of all four heavy metals, while EDDS significantly increased it. NaCl had different effects on heavy metals in terms of the translocation factor (TFc), increasing it for cadmium and decreasing it for arsenic and lead, with or without EDDS. EDDS reduced the accumulation of all heavy metals, except for zinc, in the presence of NaCl in polluted soil. The polymetallic pollutants also modified the cell wall constituents. NaCl increased the cellulose content in the MS and LB, whereas EDDS had little impact. In conclusion, salinity and EDDS have different effects on heavy metal bioaccumulation in K. pentacarpos, and this species has the potential to be a candidate for phytoremediation in saline environments. [ABSTRACT FROM AUTHOR]

Cylindrospermopsin (CYN) is a potent cyanobacterial toxin found in freshwaters worldwide. In this work, the feasibility of the photo-Fenton process under neutral pH using light emitting diodes as irradiation source for the removal of this hazardous cyanotoxin from freshwater was investigated. The impact of the kind of iron chelating agent (ethylenediamine-N, N′-disuccinic acid vs. ethylenedinitrilotetraacetic acid) as well as the effect of the main operating conditions viz. H2O2 dose, Fe(III) load, initial CYN concentration, and Fe(III):EDDS molar ratio on the performance of the process was systematically evaluated. EDDS was selected as the most appropriate iron chelating agent considering the kinetics of the process and the environmental impact (Vibrio fischeri and Artemia salina). Under optimized conditions ([H2O2] = 30 mg L−1; [Fe(III)] = 5 mg L−1; Fe(III):ligand = 1:0.5 (molar ratio)), complete removal of CYN was achieved in 15-min reaction time. Furthermore, the catalytic system showed to be effective in real water matrices (river and reservoir waters) spiked with CYN. Although the presence of inorganic ions (mainly HCO3−/CO32−) and dissolved organic carbon decreased the oxidation rate of CYN due to scavenging reactions and iron coordination, respectively, complete elimination of the cyanotoxin was achieved in all cases. The fate of EDDS along the process was also evaluated to demonstrate that the catalytic system investigated, apart from its effectiveness, warrants the complete absence of residues after reaction. Therefore, the proposed system constitutes a promising method for cyanotoxin treatment either as a drinking water treatment step in conventional plants or as a potential remediation strategy in the natural environment. [ABSTRACT FROM AUTHOR]

Toxic contaminants (metals and metal-containing compounds) are accumulating in the environment at an astonishing rate and jeopardize human health. Remarkable industrial revolution and the spectacular economic growth are the prime causes for the release of such toxic contaminants in the environment. Cadmium (Cd) is ranked the 7th most toxic compound by the Agency for Toxic Substances and Disease Registry (USA), owing to its high carcinogenicity and non-biodegradability even at miniscule concentration. The present study assessed the efficiency of four biodegradable chelants [nitrilotriacetic acid (NTA), ethylenediamine disuccinate (EDDS), ethylene glycol tetraacetic acid (EGTA), and citric acid (CA)] and their dose (5 mM and 10 mM) in enhancing metal accumulation in Solanum americanum Mill. (grown under 24 mg Cd kg−1 soil) through morpho-physiological and metal extraction parameters. Significant variations were observed for most of the studied parameters in response to chelants and their doses. However, ratio of root and shoot length, and plant height stress tolerance index differed non-significantly. The potential of chelants to enhance Cd removal efficiency was in the order — EGTA (7.44%) > EDDS (6.05%) > NTA (4.12%) > CA (2.75%). EGTA and EDDS exhibited dose-dependent behavior for Cd extraction with 10 mM dose being more efficient than 5 mM dose. Structural equation model (SEM) depicted strong positive interaction of metal extraction parameters with chelants (Z-value = 11.61, p = 0.001). This study provides insights into the importance of selecting appropriate dose of biodegradable chelants for Cd extraction, as high chelant concentration might also result in phytotoxicity. In the future, phytoextraction potential of these chelants needs to be examined through field studies under natural environmental conditions. [ABSTRACT FROM AUTHOR]

The ability of plants to accumulate heavy metals is a crucial factor in phytoremediation. This study investigated the effect of NaCl and S,S-ethylenediaminesuccinic acid (EDDS) on heavy metal accumulation in Kosteletzkya pentacarpos in soil polluted with arsenic, cadmium, lead, and zinc. The addition of NaCl reduced the bioavailability of arsenic and cadmium, while EDDS increased the bioavailability of arsenic and zinc. The toxicity of the polymetallic pollutants inhibited plant growth and reproduction, but NaCl and EDDS had no significant positive effects. NaCl reduced the accumulation of all heavy metals in the roots, except for arsenic. In contrast, EDDS increased the accumulation of all heavy metals. NaCl reduced the accumulation of arsenic in both the main stem (MS) and lateral branch (LB), along with a decrease in cadmium in the leaves of the main stem (LMS) and zinc in the leaves of the lateral branch (LLB). Conversely, EDDS increased the accumulation of all four heavy metals in the LB, along with an increase in arsenic and cadmium in the LMS and LLB. Salinity significantly decreased the bioaccumulation factor (BF) of all four heavy metals, while EDDS significantly increased it. NaCl had different effects on heavy metals in terms of the translocation factor (TFc), increasing it for cadmium and decreasing it for arsenic and lead, with or without EDDS. EDDS reduced the accumulation of all heavy metals, except for zinc, in the presence of NaCl in polluted soil. The polymetallic pollutants also modified the cell wall constituents. NaCl increased the cellulose content in the MS and LB, whereas EDDS had little impact. In conclusion, salinity and EDDS have different effects on heavy metal bioaccumulation in K. pentacarpos, and this species has the potential to be a candidate for phytoremediation in saline environments.

Degradable chelating agent–assisted phytoextraction is a promising method for the remediation of Cd-contaminated agricultural soil. However, there are limited studies that have examined the effect of chelating agents on soil solutions and soil quality in alkaline soil. In this study, the effects of S,S-ethylenediamine disuccinic acid (EDDS) on the growth and phytoextraction of Solanum nigrum L. (S. nigrum) were studied using pot experiments. The influence of EDDS on the soil solutions, heavy metal contents, and soil enzyme activities was evaluated. EDDS application increased the height of S. nigrum by 7.25–29.25 cm and increased the biomass of stem and leaf by 4.26–14.95 and 1.14–10.78 g/pot, respectively. The Cd concentrations in the leaves and berries of S. nigrum were 1.21–2.17 and 1.7–9.47 times higher than that of the control, respectively, and the Cd extraction amount in the shoots of S. nigrum increased by 22.78–256.16 μg/pot after EDDS application. The chelation of EDDS on heavy metals reached a peak after 7 days of application, decreased gradually with the degradation of EDDS, and disappeared after 30 days of application. Soil pH, available metals, metal speciation, and soil urease were significantly related to the application time of EDDS. Importantly, EDDS application 45 days before S. nigrum harvest treatments decreased the available metal concentrations and improved soil pH and urease activity. However, when EDDS was applied 15 days before S. nigrum harvest, the available Cd and Pb concentrations significantly increased and caused additional Pb pollution. Considering the chelation and degradation effects, the environmental implication, and the cost of EDDS, the results of this study showed that one application of EDDS was better than two applications, a 45-day application before harvest was preferred to a 15-day application, and application of 1–3 mM EDDS 30–45 days before S. nigrum harvest was the most promising application method for the remediation of Cd-contaminated alkaline soil. [ABSTRACT FROM AUTHOR]

Extensive research has been conducted on the utilization of a metal-based catalyst to activate peracetic acid (PAA) for the degradation of micropollutants (MPs) in water. Mn(II) is a commonly employed catalyst for homogeneous advanced oxidation processes (AOPs), but its catalytic performance with PAA is poor. This study showed that the environmentally friendly chelator ethylenediamine- N , N '-disuccinic acid (EDDS) could greatly facilitate the activation of Mn(II) in PAA for complete atrazine (ATZ) degradation. In this process, the EDDS enhanced the catalytic activity of manganese (Mn) and prevented disproportionation of transient Mn species, thus facilitating the decay of PAA and mineralization of ATZ. By employing electron spin resonance detection, quenching and probe tests, and 18 O isotope-tracing experiments, the significance of high-valent Mn-oxo species (Mn(V)) in the Mn(II)-EDDS/PAA system was revealed. In particular, the involvement of the Mn(III) species was essential for the formation of Mn(V). Mn(III) species, along with singlet oxygen ( 1 O 2 ) and acetyl(per)oxyl radicals (CH 3 C(O)O • /CH 3 C(O)OO • ), also contributed partially to ATZ degradation. Mass spectrometry and density functional theory methods were used to study the transformation pathway and mechanism of ATZ. The toxicity assessment of the oxidative products indicated that the toxicity of ATZ decreased after the degradation reaction. Moreover, the system exhibited excellent interference resistance toward various anions and humid acid (HA), and it could selectively degrade multiple MPs.

• Bioprocess for metal chelant (S,S)-ethylenediamine -N,N '-disuccinic acid (EDDS). • Removal of fumarase with IMAC and immobilization of EDDS lyase with amino carrier. • Immobilized EDDS lyase for 11 batches of EDDS synthesis (864.5 h). • EDDS concentration improved from 19.8–209.3 g/L in the reaction. • High yield (both >90 %) for biosynthesis reaction and product isolation. Ethylenediamine -N,N '-disuccinic acid (EDDS) is a promising chelating agent for the remediation of heavy metal-contaminated soil. In general, EDDS is produced through a chemical method. In this study, we report an efficient biotechnological approach for EDDS production using an immobilized enzyme. We expressed the EDDS lyase in E. coli and obtained 19.8 g/L of EDDS through a reaction catalyzed by crude enzymes, containing EDDS lyase and fumarase. After performing metal affinity chromatography-mediated purification, we thoroughly eliminated the fumarase activity, which could result in the unnecessary formation of malate. Then, the purified EDDS lyase was immobilized on a glutaraldehyde-activated amino carrier, and the immobilized enzyme was used in 11 batches (864.5 h). After optimization, 209.3 g/L EDDS was obtained in a 100 mL reaction system, resulting in 20.2 g of EDDS product with a purity of 99.8 % after isolation. The yields of reaction and isolation were 94.0 % and 91.8 %, respectively. In conclusion, this study describes a promising bioproduction process for industrial-level EDDS production. [ABSTRACT FROM AUTHOR]

Phytoextraction has been considered an effective and environment-friendly method for removing heavy metals from contaminated soil. However, the efficiency, mechanism, and adaptability of phytoextraction by hyperaccumulators in Cd-polluted weakly alkaline soil have not been investigated in detail. In this study, pot experiments were conducted to evaluate the enhanced effects of S,S-ethylenediamine disuccinic acid (EDDS) on phytoextraction in alkaline soil by measuring the degradation kinetic characteristics of EDDS and Cd absorption dynamics of Tagetes patula L. (T. patula) and Phytolacca americana L. (P. americana) for a period of 55 days. Results showed that the half-life of EDDS varied from 4.20–7.07 days and 3.35–4.36 days for T. patula and P. americana, respectively. EDDS-activated Cd reached saturation at a low dosage (1 mM) and a single application of EDDS was found to be better than double applications. The activation of EDDS on Cd applied before 45 days of harvest was better than that before 15 days of harvest, and disappeared after a 35-day application. Correspondingly, the Cd concentration in P. americana and T. patula leaves increased significantly after 3 days of the EDDS application. However, T. patula had a biomass 2.57 times and Cd absorption capacity 10.06 times higher than P. americana. EDDS showed almost no influence on the stem and leaf biomass of T. patula; however, the root weight decreased by 9.44–71.77%. The Cd concentration in T. patula leaves of all the treatments was 1.00–1.81 times that of the control group. In comparison with other treatments, the EDDS application (3 mM) before 15 days of harvest extracted the highest amount of Cd (601.45 μg/pot) in T. patula shoots, reaching 1.40 times that in the control group. Therefore, T. patula might be a more suitable phytoremediator for Cd-polluted alkaline soil than P. americana; the most effective method was the EDDS application (3 mM) before 15 days of harvest. [ABSTRACT FROM AUTHOR]

Photo-Fenton processes have been widely studied in wastewater treatment. In this research, the degradation of bisphenol A (BPA) was carried out in a new heterogeneous photo-Fenton process. The ethylenediamine-N,N′-disuccinic acid (EDDS) was used as chelating agent in this system with two different kinds of commercially available nanosized hematite (30 nm and 80 nm) addition. The results showed that the present of EDDS could enhance the degradation efficiency. And can be concluded that the degradation efficiency is better in the system with 30 nm hematite. The TEM, XRD, and specific surface area were conducted to understand the different characteristics of the two size hematite. The adsorption experiments of BPA and EDDS on hematite proved that there was little adsorption of BPA while the EDDS was adsorbed much more on hematite, which has confirmed Fe(III) and EDDS can form Fe(III)-EDDS complex. The effects of different parameters including hematite loading, H2O2, and EDDS concentrations on the degradation process were investigated. According to the results, the optimum condition for BPA degradation using 30 nm (0.8 g L−1 hematite, 0.1 mmol L−1 H2O2, and 1.2 mmol L−1 EDDS) and 80 nm (0.6 g L−1 hematite, 0.05 mmol L−1 H2O2, and 1.2 mmol L−1 EDDS) hematite were selected. It was confirmed that the ·OH plays an important role in the oxidation process through attacking the BPA molecule and produce hydroxyl addition derivative. In addition, O2 can react with electron (e−) and holes (h+) produced by iron oxide under UV irradiation to create 1O2, which could work as potential reactive species to oxidize BPA. [ABSTRACT FROM AUTHOR]

Chelates, used to increase the uptake of heavy metals in phytoremediation, can also increase the mobility of metals. If plants fail to uptake or stabilize all the mobilized metals, then subsurface soil or groundwater can be contaminated. Therefore, the type and concentration of chelate used and proper site management are important for chelate-aided phytoremediation. In this study, we evaluated potential metal leaching from the soil after applying three different chelates. The readily soluble and exchangeable metal (RSEM) and plant-available metal (PAM) of Pb, Zn, Cu, Cd, and Ni in soil amended with ethylene diamine tetra acetic acid (EDTA), ethylene diamine disuccinate (EDDS), or humic acid (HA) were analyzed, and the potential leaching factor (PLF) of the heavy metals was estimated. Results showed that the effects of chelates and their concentration on RSEM and PAM of heavy metal in soil were different. The addition of EDTA increased the CRSEM and CPAM of all heavy metals, although its effects varied with the concentration added. EDDS application increased CRSEM and CPAM of Cu, Ni, and Zn, but EDDS was more effective than EDTA for Cu and Ni. HA did not show a significant impact due to the short duration of the experiment. In most cases with chelates effects, the increase of RSEM was greater than PAM, and the potential of metal leaching increased. Therefore, application of chelates for remediation of metal-contaminated soil should consider not only the capacity of metal uptake in plants but also the potential metal leaching from the system. Additionally, this process should be accompanied by proper water management to minimize leachate in chelate-aided phytoremediation applications. [ABSTRACT FROM AUTHOR]

Employment of biosurfactants and biodegradable chelants could further promote sustainability of soil and groundwater remediation tasks. Biosurfactant (soapnut saponin) and biodegrading chelants (ethylenediamine-N,N′-disuccinic acid (EDDS)) were employed to enhance the phytoextraction by native Taiwanese chenopod (Chenopodium formosanum Koidz.), Napier grass (Pennisetum purpureum) cultivar Taishi No. 4, and soapwort (Saponaria officinalis). Ethylene diamine tetraacetic acid (EDTA) was also employed as the control. Contaminated soils as silty clay loam texture was collected from a defunct rice paddy, containing chromium (Cr), cadium (Cd), and copper (Cu). Addition of both soapnut saponin and EDDS proportionally increased bioaccumulation factors (BCFs) of aboveground biomass for all three plants. Taiwanese chenopod demonstrated the best BCF values among three plants, with BCF increased from 0.76 to 2.6 and 1.3 for Cu under the presence of the highest dosages of EDDS and saponin. Plant aboveground biomass did exhibit negative correlation toward biomass metal concentrations. Presence of saponin did exhibit the least negative slopes among the correlations of all three additives for three plants. Taiwanese chenopod did exhibit the least negative slopes among the correlations of all three additives for three plants. Above observations suggested that saponin may have some protection for plants, especially for Napier grass. Taiwanese chenopod could possess more tolerance toward heavy metals than Napier grass does. [ABSTRACT FROM AUTHOR]

• Antipyrine, caffeine, carbamazepine, ciprofloxacin and sulfamethoxazol were completely degraded. • Solar/Fe/H 2 O 2 and solar/Fe/S 2 O 8 2− system mediated by EDDS have been compared. • Different Fe:EDDS ratios, initial iron species and oxidant agents have been tested. • Best ratio for solar/Fe:EDDS/H 2 O 2 was 1:2 and 1:1 for solar/Fe:EDDS/S 2 O 8 2−. The main purpose of this pilot plant study was to compare degradation of five microcontaminants (MCs) (antipyrine, carbamazepine, caffeine, ciprofloxacin and sulfamethoxazole at 100 μg/L) by solar photo-Fenton mediated by EDDS and solar/Fe:EDDS/S 2 O 8 2−. The effects of the Fe:EDDS ratio (1:1 and 1:2), initial iron species (Fe(II) or Fe(III) at 0.1 mM) and oxidizing agent (S 2 O 8 2− or H 2 O 2 at 0.25–1.5 mM) were evaluated. The higher the S 2 O 8 2− concentration, the faster MC degradation was, with S 2 O 8 2− consumption always below 0.6 mM and similar degradation rates with Fe(II) and Fe(III). Under the best conditions (Fe 0.1 mM, Fe:EDDS 1:1, S 2 O 8 2− 1 mM) antipyrine, carbamazepine, caffeine, ciprofloxacin and sulfamethoxazole at 100 μg/L where 90% eliminated applying a solar energy of 2 kJ/L (13 min at 30 W/m2 solar radiation <400 nm). Therefore, S 2 O 8 2− promotes lower consumption of EDDS as Fe:EDDS 1:1 was better than Fe:EDDS 1:2. In photo-Fenton-like processes at circumneutral pH, EDDS with S 2 O 8 2- is an alternative to H 2 O 2 as an oxidizing agent. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Photo-Fenton with Fe3+-EDDS removes CECs regardless water composition. • 80% CEC removal after 15 min in 5 real WWTP effluents. • Nature and not the load of organic matter has impact on CEC removal. • Short reaction time to remove CECs encourages continuous flow operation. • Mechanism developed with synthetic effluent explains reactions in real wastewater. Abstract This paper presents for the first time the treatment of contaminants of emerging concern (CECs) in a systematic study in different municipal wastewater treatment plants (MWWTPs) of the Mediterranean area, more than 1000 km away. Solar photo-Fenton process at neutral pH with Fe3+-EDDS has been demonstrated to be very efficient under controlled conditions and must be validated in realistic and variable conditions such as real MWWTP effluents of different composition. To this end, CEC removal was studied in effluents from 5 treatment plants in the Mediterranean area of Spain, the inorganic and organic composition varying in the range 161–641 mg L−1 (sulfate), 133–538 mg L−1 (chloride) and 10–20 mg L−1 (dissolved organic carbon). More than 45 CECs were quantified in MWW and results showed that the effect on CEC elimination of the concentration of anions and organic matter was interfered by the nature of the organic matter. However, origin and composition of MWW was not critic for attaining >80% degradation of CECs after 15 min of reaction. Moreover, conventional anions (sulfate, chloride) had a positive effect on CEC degradation rate. This paper demonstrates the consistency and predictability of the solar photo-Fenton process at circumneutral pH for treating CECs in simple and cheap photoreactors. [ABSTRACT FROM AUTHOR]

The effects of Ethylenediamine disuccinic acid (EDDS) (0 and 5 mmol·kg−1) as a synthetic chemical amendment, vermicompost (0 and 5%w/w) as an organic amendment and their combined application were evaluated for the phytoextraction by sunflower (Helianthus annuus L.) of cadmium (Cd) and lead (Pb) at three artificial contamination levels in soils (0, 50, and 100 mg·kg−1 for Cd and 0, 100, and 200 mg·kg−1 for Pb). The results showed that the application of EDDS was the most effective method to increase Pb and Cd concentrations in both parts of the plant. The results also showed that the application of EDDS increased 9.27% shoot Pb content at 200 mg·kg−1 but decreased 15.95% shoot Cd content at 100 mg·kg−1 contamination level with respect to the respective controls. The bioavailable concentrations of Cd at 100 mg·kg−1 and Pb at 200 mg·kg−1 contamination level in the soil at the end of experiment increased 25% and 26%, respectively after the application of EDDS but vermicompost decreased 43.28% the bioavailable Pb concentration relative to their controls. Vermicompost increased the remediation factor index of Cd, thus making it the best treatment for the phytoextraction of Cd. The combined application of EDDS and vermicompost was the best amendment for Pb phytoextraction. [ABSTRACT FROM AUTHOR]

Highlights • EDDS-improved nano Pd/Fe system was established and used for 2,4-D dechlorination. • 2,4-D dechlorination efficiency and process with and without EDDS were compared. • Nano Pd/Fe particles with and without EDDS were characterized by SEM, XPS and XRD. • EDDS can inhibit the formation of passivation layer and enhance nPd/Fe reactivity. • The reaction mechanism has been discussed and presented in the figures. Abstract In the current study, the reaction system of ethylenediamine disuccinic acid (EDDS, a green and biodegradable chelating agent) improved nanoscale Pd/Fe was successfully established for effective dechlorination of 2,4-dichlorophenoxyacetic acid (2,4-D). The effects of different experimental parameters including EDDS dosage, initial pH, palladium ratio and reaction temperature on 2,4-D dechlorination were investigated. The results demonstrated that higher chelating agent dosage and palladium ratio, appropriate reaction temperature (20.0–35.0 °C) and a lower initial pH were beneficial for the efficient reductive dechlorination of 2,4-D. Over 99.5% of 2,4-D removal and 97.3% of phenoxyacetic acid (PA) generation were reached within just 50 min reaction time under these experimental conditions: 20.0 mmol L−1 EDDS concentration, 1.0 g L−1 nZVI content, initial pH 5.5, palladium loading 0.50%, reaction temperature 25.0 °C and stirring speed 200 r min−1. Characterization tests revealed that EDDS successfully removed the passivation layer on the nano-iron surface and thus exposed more surface active sites. In addition, EDDS chelated iron ions in the solution generated more soluble complex inhibiting the formation of inert layer on nanoscale Pd/Fe particles surface. As a result, the reactivity of nanoscale Pd/Fe was increased significantly. Findings from the present study suggested that the EDDS could be a promising substitute to enhance Pd/Fe reactivity and dechlorination efficiency. [ABSTRACT FROM AUTHOR]

In the present study, biodegradable ligand EDDS was employed to assist ZVI on simultaneous remediation of PCB and heavy metals co-contaminated soils under aerobic condition. With addition of 4 mmol L −1 EDDS and 5 g L −1 ZVI, the total removal ratio of PCB reached 75.3%, and the stabilization ratio of Pb and Cu attained 97.1% and 91.9% respectively. EDDS played two key roles during the process. Firstly, the addition of EDDS could enhance hydroxyl radical generation by ZVI and oxygen for the oxidation of PCB including distribution in the soil phase and dissolved form in the aqueous phase. Secondly, free EDDS could accelerate the release of Cu and Pb from the soil phase to the aqueous phase. As the oxidation of EDDS and the increase of pH value during the process, the dissolved Cu and Pb could be efficiently stabilized by iron oxyhydroxide through coprecipitation. Compared with ZVI/Air, ZVI/EDDS/Air treatment could significantly enhance the stabilization of Pb and Cu. The reason was the dissolution of Cu and Pb by EDDS extraction could reduce the mass transfer limitations between heavy metals and iron oxyhydroxide. Therefore, our study suggests a promising alternative for remediation of organic compounds and heavy metals co-contaminated soil. [ABSTRACT FROM AUTHOR]

Copyright of Yuzuncu Yil Universitesi Journal of Agricultural Sciences (YYU J Agr Sci) is the property of Yuzuncu Yil University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For removing potentially toxic elements (PTEs) from field-contaminated soils, cost-effective soil remediation has been a worldwide concern. As one of the widely employed techniques, chelant-enhanced phytoremediation can remove PTEs with marginal impact on the soil properties, yet the newly formed metal-chelant complexes cannot be completely captured and extracted by the plants. This arouses concerns about downstream migration and secondary contamination of the metal-chelant complexes and free chelant. Organic amendments, such as food waste compost (FWC), may stabilize metals and/or metal-chelant complexes, improve soil properties and plant growth, and reduce waste volume. Therefore, FWC may provide a solution for the migration of metal-chelant complexes and free chelant. Two chelants were selected in this study: EDTA (ethylene-diaminetetraacetic-acid) and its biodegradable isomer EDDS ([ S,S ]-ethylenediaminedisuccinic acid). The interactions between FWC and metals, metal-EDTA/metal-EDDS complexes in a field-contaminated soil (mainly by Cu, Zn, and Pb) were investigated. Batch adsorption isotherms indicated a strong adsorption capacity of FWC for uncomplexed Cu, Zn, and Pb ions. Significant adsorption of Pb-EDDS (∼100%), Zn-EDDS (>77%), and Cu-EDTA (36–76%) complexes on the FWC was found at apparent equilibrium. The adsorption capacity of Cu-EDDS (32–38%), Pb-EDTA (∼20%), and Zn-EDTA (∼0%) complexes was limited. However, the co-existence of FWC and EDDS increased the mobilization of Cu and Zn, while the co-existence of FWC and EDTA reduced the available amounts of Cu and Pb in solution. Metal speciation calculation showed that nearly all extracted Cu, Zn, and Pb were complexed with chelants in the solution, while notable amount of dissolved Fe (but not Al and Ca) was associated with dissolved organic matter. In this study, FWC can be useful for minimizing the unintended leaching of Cu- and Pb-EDTA complexes in EDTA-enhanced phytoremediation, yet it might be less suitable for the case of EDDS. A novel integration of recycled waste can enhance the effectiveness of sustainable remediation of contaminated soils. [ABSTRACT FROM AUTHOR]

Abstract This article presents the psychometric properties for the Portuguese population of a brief self-report scale for diagnosing anorexia nervosa (AN), bulimia nervosa (BN), and binge-eating disorder (BED): the Eating Disorder Diagnostic Scale (Stice et al., 2000). Method To study the psychometric properties of EDDS, an exploratory factor analysis was done first, followed by a confirmatory factor analysis. Results The results of the exploratory factor analysis revealed the existence of three components and the confirmatory factor analysis showed a structure with three latent variables (Body and Weight Concerns, Binge Eating Behaviour and Compensatory Behaviours), with a second order variable (Eating Disorder Symptoms) with a good adjustment fit. The internal consistency and the test–retest correlations revealed an adequate reliability and the inter-correlations of the EDDS subscales with other measures of the same and different constructs, supported the convergent and discriminant validity of this measure. Conclusions Summing up, the EDDS seems to be a useful measure to assess eating disorders symptomatology in the Portuguese population. [ABSTRACT FROM AUTHOR]

S,S-ethylenediamine-N,N-disuccinic acid (EDDS) enhanced reductive dissolution of α-FeOOH by Shewanella putrefaciens CN32 (CN32), resulting in formation of surface-bound Fe(II) species ( Fe II EDDS) to improve reductive dechlorination of carbon tetrachloride (CT). The pseudo-first-order rate constants for bio-reduction extents of α-FeOOH by CN32 in the presence of 1.36 mM EDDS was 0.023 ± 0.0003 d −1 which was higher than without EDDS. The enhancement mechanism of bio-reduction was attributed to the strong complexation ability of EDDS to formed Fe III EDDS, which could be better utilized by CN32. The dechlorination kinetic of CT by Fe II EDDS (2.016 h −1 ) in the presence of 1.36 mM EDDS was 24 times faster than without EDDS. Chloroform were detected as main products for the degradation of CT. The chemical analyses and morphological observation showed that combination between EDDS and Fe 2+ produced Fe II EDDS complex, which had a reductive potential of −0.375 V and significantly enhanced CT dechlorination. The results showed that EDDS played an important role in enhancing the bio-reduction of α-FeOOH to accelerate reductive dechlorination of CT. [ABSTRACT FROM AUTHOR]

This paper presents the results of an experimental study aimed at investigating the applicability of ethylenediamine-N,N0-disuccinic acid (EDDS) as a washing solution for the remediation of Pb-contaminated soil. All aspects of the treatment are analyzed and optimized, including the reuse and the final disposal of the EDDS spent solution. Different molar concentrations of the washing solutions and the efficiencies of varying solid/liquid ratio are tested at different pH values. More than 90% of the mobile Pb fraction is removed in about 24 h at pH 6. Accordingly, soil toxicity strongly decreases as a consequence of the treatment. The regenerated solution exhibits a reduced, but not negligible, extractive capacity. The total extraction of Pb is approximately 50% of the initial value after one regeneration cycle, and almost 20% after a second regeneration cycle. Respirometric tests, conducted using an activated sludge sampled in a municipal wastewater treatment plant, indicate that the spent solutions are not biodegradable, but they do not exert any toxic effect on the biomass. On the contrary, tests on regenerated solutions displayed the same biodegradability as the fresh ones. [ABSTRACT FROM AUTHOR]

The present work had two purposes firstly to evaluate the potential of Lantana Camara for phytoextraction of heavy metals from fly ash amended soil and to assess the suitability of a proper biodegradable chelating agent for chelate assisted phytoextraction. Plants were grown in manure mixed soil amended with various concentration of fly ash. Two biodegradable chelating agents were added (EDDS and MGDA) in the same dose separately before maturation stage. Sampling was done at different growing stages. The plant took up metal in different plant parts in the following order: for Cu, and Zn leaf >root >stem, for Cr and Mn leaf>stem >root, for Ni root >leaf>stem and for Pb root≈leaf>stem respectively. For Cu, Zn, Cr and Mn Lantana camara acted as phytoextractor. Translocation factor and bioaccumulation coefficient was>1 signifying enrichment and translocation of metals in the plant. Morphological studies showed no toxicity symptom in the plant. Among biochemical parameters protein and nitrate reductase activity decreased, whereas, chlorophyll and peroxidise activity increased with the growth stages. Finally, it was evident from the results that Lantana Camara can be used as efficient phytoextractor of metals, with proper harvesting cycle and both chelate were proved as effective chelators for phytoextraction of metals. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study aimed at verifying the efficiency of a double-stage remediation process to be applied in former agricultural sites contaminated by illegal dumping of industrial wastes. The process, which includes an EDDS (Ethylenediamine-N,N′-disuccinic acid) enhanced washing, followed by a phytoremediation treatment, is applied at the lab scale for the remediation of a soil sampled in a territory known as Land of Fires (Italy) contaminated with Cu (∼400 mg kg −1 ) and Zn (∼250 mg kg −1 ). Phytoremediation is conducted using Lactuca sativa to verify, together with process efficiency, the potential risks due to metal accumulation in edible species. The results of the washing process show the possibility of removing the potential toxic metals from 44% to 77% for Cu and from 18% to 47% for Zn. The removal is well distributed among all soil fractions. There is almost no removal of other components which are fundamental for an agricultural soil. Results of the subsequent phytoremediation treatment indicate that both the contaminants and the residual EDDS/EDDS-chelates adsorbed into the soil generally negatively affect plant growth, reducing the number of germinated seeds up to 43%, and the shoot length up to 63%. Nonetheless, whenever the efficiency of the washing stage is high enough, no adverse effect is obtained on the plants. The efficiency of the phytoremediation stage mainly relies on leaf uptake, which accounts for up to 88% of the total removed Cu and up to 95% of the total removed Zn. Stabilization in the underground part of the plant is more contained because of the limited mass of the roots. [ABSTRACT FROM AUTHOR]

Chelant-enhanced phytoextraction method has been put forward as an effective soil remediation method, whereas the heavy metal leaching could not be ignored. In this study, a cropping-leaching experiment, using soil columns, was applied to study the metal leaching variations during assisted phytoextraction of Cd- and Pb-polluted soils, using seedlings of Zea mays, applying three different chelators (EDTA, EDDS, and rhamnolipid), and artificial rainfall (acid rainfall or normal rainfall). It showed that artificial rainfall, especially artificial acid rain, after chelator application led to the increase of heavy metals in the leaching solution. EDTA increased both Cd and Pb concentrations in the leaching solution, obviously, whereas EDDS and rhamnolipid increased Cd concentration but not Pb. The amount of Cd and Pb decreased as the leaching solution increased, the patterns as well matched LRMs (linear regression models), with R-square ( R ) higher than 90 and 82% for Cd and Pb, respectively. The maximum cumulative Cd and Pb in the leaching solutions were 18.44 and 16.68%, respectively, which was amended by EDTA and acid rainwater (pH 4.5), and followed by EDDS (pH 4.5), EDDS (pH 6.5), rhamnolipid (0.5 g kg soil, pH 4.5), and rhamnolipid (pH 6.5). [ABSTRACT FROM AUTHOR]

This study examined the feasibility of nanoscale zero-valent iron (nZVI) for the single and combined removal of Cr(VI) and Cd(II) with or without ethylene diamine disuccinic acid (EDDS). The effects of pH and dissolved oxygen (DO) on the removal process were investigated. Results show that the single removal of either Cr(VI) or Cd(II) by nZVI was pH dependent, where the higher Cr(VI) removal was achieved under acidic conditions, whereas the higher Cd(II) removal was achieved under alkaline conditions. The presence of DO enhanced Cd(II) removal but inhibited Cr(VI) removal under alkaline conditions. In the co-existence of Cr(VI) and Cd(II), it was found that Cd(II) exerted insignificant effect on Cr(VI) removal, while the presence of Cr(VI) remarkably enhanced the Cd(II) removal. The addition of EDDS exhibited different influences on Cr(VI) and Cd(II) removal, which were associated with pH and DO. The EDDS enhanced Cr(VI) removal at pH 5.6-9.0 in the absence of DO, but decreased Cr(VI) removal at pH 9.0 in the presence of DO. For the removal of Cd(II) at pH 5.6-7.0, either facilitation or inhibition effect of EDDS was observed, depending on EDDS concentration and the co-existence of Cr(VI). However, Cd(II) removal was always significantly inhibited by EDDS at pH 9.0. [ABSTRACT FROM AUTHOR]

In a screenhouse experiment, we investigated the role of two environment friendly chelants, Ammonium molybdate and EDDS for Pb mobilisation and its extraction by Coronopus didymus under completely randomized controlled conditions. Seedlings of C. didymus were grown in pots having Pb-contaminated soil (1200 and 2200 mg kg −1 ) for 6 weeks. Plants were harvested, 1 week after the addition of A. molybdate and EDDS. Results revealed that A. molybdate and EDDS enhanced the uptake and accumulation of Pb in roots and shoots of C. didymus . At 2200 mg kg −1 Pb level, compared to Pb-alone treatment, the maximal concentration of Pb was increased upto ∼10% and ∼19%, in roots whereas ∼8% and ∼18%, respectively, in shoots on addition of 2 mmol kg −1 A. molybdate and EDDS. Additionally, Pb + EDDS treatments enhanced the plant biomass and triggered strong antioxidative response, more efficaciously than Pb + A. molybdate and Pb-alone treated plants. In this study, EDDS relative to A. molybdate was more efficient in mobilising and extracting Pb from soil. Although, EDDS followed by A. molybdate had good efficacy in mitigating Pb from contaminated soils but C. didymus itself has the inherent affinity to tolerate and accumulate Pb from contaminated soils and hence in future, can be used either alone or with some other eco-friendly amendments for soil remediation purposes. [ABSTRACT FROM AUTHOR]

This study evaluated the hypothesis that the organic chelant ethylenediamine- N, N′-disuccinic acid (EDDS) mitigates plant damage under salinity, and that this is accomplished by EDDS-induced effects on cation uptake. Damaging effects of salinity on plants often involve inhibited uptake of nutritional cations, such as K and Ca, and excessive accumulation of Na. Therefore, mechanisms that improve uptake of K and Ca, or reduce Na uptake, have a potential for ameliorating salinity damages. Organic chelants increase heavy-metal cation availability at the site of uptake and increase their uptake by the roots or in planta transport. Although organic chelants are routinely used in agriculture to enhance uptake of heavy-metal cations into plants, and for soil bioremediation, their effect on uptake of cation-macronutrients is not known, and neither is their impact on plant function under salinity. In this study, we evaluated the response of strawberry plants to EDDS application (0, 1, 3 and 5 mmol kg soil−1), under six levels of NaCl (0, 3, 6, 9, 12 and 15 mmol L−1). EDDS application under salinity improved vegetative development, as well as reproductive growth and chlorophyll content, with statistically significant interaction between chelant dosage and level of salinity. The mitigation of salinity damage by EDDS occurred at high salinity treatments (from 9 mM NaCl). Application rates of 1-3 mmol EDDS kg−1 were optimal for mitigating salinity effects on reproductive development, but in accordance with the extent of chelant-induced accumulation of the macronutrients K, Ca and P in the leaves, higher application rates (3-5 mmol EDDS kg−1) were required for optimal improvement of vegetative development. These results suggest that EDDS improves plant function under mild salinities by interfering with salinity effects on the plant ionome. [ABSTRACT FROM AUTHOR]

The occurrence of new emerging contaminants in surface waters has recently grabbed increased attention of the scientific community. The adoption of Advanced Oxidation Processes (AOPs) represents an efficient strategy to remove recalcitrant compounds from aqueous streams and achieve high mineralization levels. Amongst AOPs, the photo-Fenton process has been widely investigated due to the possibility of using a renewable energy source (i.e., solar energy) and low concentration of catalyst. On the other hand, the use of photo-Fenton process is restricted to acidic pH values, with associate high operating costs for industrial scale applications. To overcome these drawbacks, photo-Fenton processes modified by adding selected chelating agents can be successfully performed at neutral pH. The present review aims at examining and comparing the most relevant papers dealing with photo-Fenton processes at neutral pH that appeared in the literature so far. Such papers were classified by chelating species adopted. In particular, for each iron(III)-ligand complex, the mechanism of photolysis, the speciation diagram, the light absorption properties, the quantum yields, biodegradation and toxicity, and some example of applications are reported. As a conclusion, suitable criteria for choosing chelating agent and operating conditions in photo-Fenton processes at neutral pH are proposed. [ABSTRACT FROM AUTHOR]

This study shows solar photo-Fenton combined with nanofiltration (NF) to treat microcontaminants (MCs) in actual MWTP effluents. Photo-Fenton was operated at circumneutral pH using (S,S)-Ethylenediamine-N,N'-disuccinic acid trisodium salt (EDDS) as the iron complexing agent (Fe:EDDS in a molar ratio of 1:2) and compared with classical photo-Fenton at pH3. Starting H2O2 concentration was 50 mg/L and Fe was 0.1 mM or 0.2 mM. MC degradation was over 90% in all cases and 35 different MCs were monitored by Liquid Chromatography-Mass Spectrometry enabling the two processes to be compared under real conditions. NF pretreatment enabled photocatalysis to be run at lower flow rates and with higher starting concentrations reducing the surface area of solar collectors and reagents needed. Acute and chronic toxicity tests were also carried out before and at the end of each treatment evaluated and it seemed clear that MC degradation did not produce intermediates with any significant effect on toxicity. In addition, a detailed economic assessment was also performed. Operating costs were higher at circumneutral pH (0.76 €/m³) with EDDS than with classical photo-Fenton at pH3 (0.48 €/m³). [ABSTRACT FROM AUTHOR]

Phytoextraction is a green remediation technology for cleaning contaminated soils. Application of chelating agents increases metal solubility and enhances phytoextraction. Following a successful greenhouse experiment, a panel study under field weather elucidated the efficiency of the chelating agent ethylenediaminedisuccinic acid (EDDS) on phytoextraction of lead (Pb) by vetiver grass, a hyperaccumulator of Pb, and a nonaccumulator fescue grass from residential soils contaminated with Pb-based paint from Baltimore, MD and San Antonio, TX. Three soils from each city with Pb content between 1000 and 2400 mg kg −1 were chosen for the panel study. Sequential extraction revealed that Fe-Mn oxide (60–63%) and carbonate (25–33%) fractions of Pb dominated in Baltimore soils, whereas in San Antonio soils, Pb was primarily bound to the organic fraction (64–70%) because organic content was greater and, secondarily, to the Fe-Mn oxide (15–20%) fraction. Vetiver and fescue grasses were transplanted and grown on wood panels in the field with EDDS applied after 3 months and 13 months. Soil and leachate results indicated that EDDS applications increased Pb solubility in soils. Plant tissues results indicated enhanced the uptake of Pb by vetiver and showed that EDDS application promoted translocation of Pb from root to shoot. Average Pb concentration increased by 53% and 203% in shoots and by 73% and 84% in roots of vetiver after the first and second applications of EDDS, respectively. Concentrations in roots and shoots increased in all tested soils, regardless of soil pH or clay content. After the second application, average Pb concentrations in vetiver were higher than those in fescue by 3.6x in shoots and 8.3x in roots. Visual phytotoxic symptoms from increased bioavailable Pb from EDSS applications were observed in fescue but not in vetiver. This study demonstrated the potential of a chemically-catalyzed phytoremediation system as a cleanup method for lead-contaminated soils. [ABSTRACT FROM AUTHOR]

Purpose: A risk-based approach commonly applied for Pb-contaminated soil is stabilisation by phosphate amendment. However, the proportion of Pb present in a form that is readily immobilised by phosphate addition is often limited. Chelates were examined as a means to mobilise Pb prior to immobilisation to increase the proportion of Pb that could react with phosphate. Four contrasting shooting range soils from around Australia (Murray Bridge (MB), Townsville (TV), Darwin (DA) and Perth (PE)) were used for the study. Materials and methods: Chelating agents such as ethylenediaminetetraacetic acid (EDTA) are able to extract Pb from existing species in the soil, forming complexes. By lowering soil pH or adding Fe for the displacement of Pb from the complex, a greater proportion of Pb may be available for reaction with phosphate. The use of biodegradable ethylenediamine- N, N′-disuccinic acid (EDDS) minimises residual effects of chelate treatment in the soil. Results and discussion: EDTA was not found to be suitable due to the stability of the chelate-Pb complex. The addition of EDDS had variable effect between the four shooting range soils. In the strongly weathered oxidic TV and DA soils, applying EDDS prior to phosphate amendment produced greater reduction in bioaccessible Pb, but in the less weathered MB and PE soil, bioaccessible Pb was increased. Water-extractable (WE) Pb increased in the soils by EDDS application, but this could be offset by lime application in DA soil, without negatively affecting Pb bioaccessibility; WE Pb also decreased over time when ammonium nitrate was added to the soil. Conclusions: Application of EDDS may be able to increase the proportion of Pb that reacts with phosphate in the soil, providing greater reduction in bioaccessible Pb than phosphate-only treatments. Additional treatability studies are needed to test amendments that could manage the water-extractable portion of Pb and to optimise application of EDDS for the best outcome. [ABSTRACT FROM AUTHOR]

Chromium (Cr) and copper (Cu) are pollutants with a strong environmental impact. 'Green biotechnology' as phytoremediation represents a sustainability opportunity for soil reclamation. In this study, we evaluated the possibility to reclaim agricultural soils located in the Solofrana valley, contaminated by Cr or Cu. Chromium contamination derives by repeated flooding events of Solofrana rivers containing Cr because of leather tanning plants, while Cu soil pollution was due to the use of Cu-rich pesticides in agriculture. Both metals showed a very low bioavailability. In order to perform an assisted phytoremediation of polluted fields, we carried out a preliminary ex situ experimentation testing for the first time sunflowers (cv. Pretor) and chelants (ethylenediaminetetraacetic acid (EDTA) and/or ethylene diamine disuccinate (EDDS)), useful when metal bioavailability is low. No symptoms of toxicity were observed in sunflowers grown on both soils, while biomass was improved when EDDS was added. Cr and Cu bioavailability was only slightly enhanced by chelants at the end of the treatments. Both Cr and Cu were mainly accumulated in the roots; moreover, Cu was also translocated to the aboveground organs in the presence of EDTA. The ex situ experimentation demonstrated that assisted phytoremediation is a very slow process not useful in the case of persistent pollution. [ABSTRACT FROM AUTHOR]

In this research, magnetite and ethylenediamine-N,N′-disuccinic acid (EDDS) are used in a heterogeneous photo-Fenton system in order to find a new way to remove organic contaminants from water. Influence of different parameters including magnetite dosage, EDDS concentration, HO concentration, and pH value were evaluated. The effect of different radical species including HO and HO /O was investigated by addition of different scavengers into the system. The addition of EDDS improved the heterogeneous photo-Fenton degradation of bisphenol A (BPA) through the formation of photochemically efficient Fe-EDDS complex. This effect is dependent on the HO and EDDS concentrations and pH value. The high performance observed at pH 6.2 could be explained by the ability of O to generate Fe(II) from Fe(III) species reduction. GC-MS analysis suggested that the cleavage of the two benzene rings is the first degradation step followed by oxidation leading to the formation of the benzene derivatives. Then, the benzene ring was opened due to the attack of HO radicals producing short-chain organic compounds of low molecular weight like glycerol and ethylene glycol. These findings regarding the capability of EDDS/magnetite system to promote heterogeneous photo-Fenton oxidation have important practical implications for water treatment technologies. [ABSTRACT FROM AUTHOR]

Chelate-assisted phytoextraction is proposed as an effective approach for the removal of heavy metals from contaminated soil through the use of high biomass plants. The aim of the present study was to compare the efficiency of the two chelators: EDTA and biodegradable EDDS in enhancing Cu uptake and translocation by Brassica napus L. grown on moderately contaminated soil and treated with increasing concentrations of EDTA or EDDS. Increasing amounts of EDDS caused serious growth suppression of B. napus and an increase in shoot metal concentrations. Growth suppression limited the actual amount of phytoextracted Cu at high concentrations of EDDS. The maximum amount of extracted Cu was achieved by the application of 8.0 and 4.0+4.0 mmol kg-1 EDDS. The shoot Cu concentrations after EDTA application were much lower than with EDDS at the same doses. According to these experiments, EDTA does not appear to be an efficient amendment if Cu phytoextraction with B. napus is considered but EDDS is.

Chromium (Cr) in the soil is one of the major pollutants for agricultural production. This study examined the efficiency of sunflower plants to remediate Cr-contaminated soils using a plant growth regulator, 5-aminolevolinic acid (ALA). At six leaf stage, sunflower plants were exposed to soil-applied Cr (0.15 g kg−1), manganese (Mn, 0.3 g kg−1) and trisodium (S,S)-ethylenediamine-N,N′-disuccinic acid (EDDS, 2.5 mmol kg−1), ALA (10 mg L−1) was sprayed. After ALA treatment, the plants were harvested for further biochemical analyses. Results showed that EDDS and Mn improved the Cr accumulation but restrained plant growth. Conversely, ALA improved the growth of Cr-stressed plants by promoting chlorophyll concentration in the top fully expanded leaves. The bioaccumulation quantity and removal efficiency of sunflowers treated by Cr + EDDS + ALA was improved by 47.92% and 47.94%, respectively, as compared to the Cr treatment. This was further supported by qRT-PCR analysis, where the expression of heavy metal transport genes such as ZIP6 and NRAMP6 and subsequently Cr accumulation in sunflower tissues increased by EDDS, Mn, and ALA application. However, compared with other treatments, ALA ameliorated cellular injury from Cr-stress by uptake or movement of Cr prevention, modulation of antioxidant enzymes, and elimination of reactive oxygen species. Our study suggested that ALA as an ideal option for the phytoremediation of Cr-contaminated soils. • ALA significantly protected sunflower from Cr and chelators stresses. • ALA protected plants by reducing the accumulation of Cr in sunflower and provoking antioxidant mechanisms. • Effects of Mn and ALA on protection of sunflower under Cr stress by promoting chlorophyll synthesis and reducing ROS accumulation. • The growth of plants is inhibited by Cr stress, which disrupts normal metabolism by damaging cell structures. [ABSTRACT FROM AUTHOR]

Pb and Ni generally are stable associated with soil and sediment matrix rendering less phytoextraction efficiency. Sunflowers are selected for phytoremediation in this study. By integrating a plant growth hormone, GA 3 , as well as environmentally friendly and bio-degradable chelating agent, EDDS, this study aims to improve the effectiveness of the heavy metal contamination remediation via phytoremediation, thereby achieving environmental sustainability. The height and weight of the plants grown in the soil at a concentration level of Pb two times higher than regulatory standards performed worse than those at a concentration level one times higher than regulatory standards. The result indicates that the higher the Pb concentration level of the soil, the stronger the impact of toxicity to plant growth will be. The group with EDDS+GA 3 is more suitable to be applied to the phytoremediation of soil at a concentration level of Ni two times higher than regulatory standards. DGGE analysis is conducted by using gradient screening after enlarging and purifying DNA sections. When a band appears, it indicates the dominant bacteria group. As a result, the more bands in a sample, the richer bacterial flora in the sample, and the higher possibility of diverse microorganisms. Intergrated phytoremediation has been proposed in this study. [ABSTRACT FROM AUTHOR]

Chelate-assisted phytoextraction with biodegradable chelants has been demonstrated as an efficient method to enhance heavy metal remediation efficiency by plants, while there is little available information on phytostabilization. A pot experiment was conducted to investigate the effects of biodegradable [S,S]-ethylenediaminedisuccinic acid (EDDS) and nitrilotriacetic acid (NTA) on plant growth and Pb accumulation of Pb phytostabilizer Athyrium wardii (Hook.) grown in Pb contaminated soils and to explore the feasibility of chelate-assisted phytostabilization. Greater adverse effects on plant biomass under high EDDS treatments were observed than NTA treatments. Significant increase of shoot Pb concentrations of A. wardii was noticed with increasing NTA and EDDS dosages, while EDDS induced higher shoot Pb concentrations than NTA. Moreover, root Pb concentrations of A. wardii under NTA treatments were 1.18–1.28-time higher than EDDS treatments, and a peak value of root Pb concentrations was observed at 2 mmol kg −1 of NTA. Shoot Pb accumulations significantly increased with increasing dosages, and EDDS treatments caused a 1.44–1.6-time increase of shoot Pb accumulation than NTA. Root Pb accumulations under NTA treatments were 1.18–1.28-time higher than EDDS treatments. Maximum root Pb accumulation (155.5 mg plant −1 ) was found at 2 mmol kg −1 of NTA on the 14th day. Higher BCF values and lower TF values were found under NTA treatments as compared to EDDS treatments. Available Pb concentrations in soil significantly increased on the 7th day with increasing NTA and EDDS dosages, then gradually decreased on the 14th day. Soil pH slightly decreased with increasing NTA and EDDS dosages. Therefore, chelate-assisted phytostabilization could be a feasible way to enhance the efficiency of Pb phytostabilization by A. wardii . [ABSTRACT FROM AUTHOR]

A green reagent of ethylenediamine- N,N'-disuccinic acid (EDDS) was reported herein for reduction of graphene oxide (GO) with microwave assistance. The characteristics of EDDS reduced graphene oxide (ERG), and the tetracycline (TC) adsorption behavior of ERG was investigated. The results showed that the deoxygenation efficiency of GO strongly depended on the EDDS amount and the ERG can be successively obtained by recycled EDDS. The ERG obtained at EDDS/GO ratio of 5 (ERG5) exhibited a maximum capacity of 558.66 mg/g for TC adsorption, which is superior to GO and ERGs obtained at other EDDS/GO ratio. The adsorption reached equilibrium within 10 min, and the driving forces are likely the van der Waals forces, π-π electron-donor-acceptor (EDA) interaction and cation-π bonding between TC and the ERG surface. The adsorbent dose, pH, temperature, initial TC concentration, and ionic strength significantly affect the TC adsorption. The pseudo-second-order kinetics describes TC adsorption process very well, with correlation coefficients ( R ) greater than 0.99. The adsorption isotherm was best fitted by Freundlich equation, followed by Langmuir, Temkin, and Hill model equations. Analysis on adsorption thermodynamics shows that the adsorption is a spontaneous endothermic process. The ERG could be a cost-effective and promising sorbent for TC wastewater treatment due to its high-efficiency performance in real river water, medical wastewater, and municipal wastewater. [ABSTRACT FROM AUTHOR]

This study demonstrated that soil washing using ethylenediaminedisuccinic acid (EDDS) as a chelating agent was efficient at removing copper and zinc from real polluted soils. Only the exchangeable and reducible fractions of Cu and Zn were extracted by EDDS. Intra-particle diffusion was the main rate controlling step in this extraction of heavy metals from the solid matrix. Different contributions were found by applying the Weber and Morris intraparticle diffusion model resulting from the different roles of superficial and intra-particle diffusive processes.The diffusion coefficients of the Cu/EDDS and Zn/EDDS complexes in real contaminated soils were estimated using simplified diffusive models (based on Crank’s and Vermeulen's approximations). The relationship between the grain size and diffusion coefficient was also evaluated. In particular, the intraparticle diffusion coefficients increased with increasing the particle size, thus indicating that the smallest granulometric fractions are characterized by a higher percentage of micropores than the largest fractions. [ABSTRACT FROM AUTHOR]

In the reduction of Cr(VI) by nanoscale zero-valent iron (nZVI), the reactivity of nZVI drops overtime due to surface passivation, which severely inhibits its effective utilization. This study investigated the effect of EDDS (ethylene diamine disuccinic acid) on the Cr(VI) reduction by nZVI at different pH (5.6, 7.0 and 9.0) and the underlying mechanisms. The removal of Cr(VI) by nZVI increased from around 60–100% as the concentration of EDDS increased from 0 to 4–5 mM at pH 5.6–7.0. It was proposed that the EDDS chelated with the generated Cr(III)/Fe(III) and inhibited their co-precipitation onto nZVI surface. However, under alkaline condition (pH 9.0), the EDDS slightly decreased the Cr(VI) reduction, which was due to the fact that the EDDS facilitated the reaction between nZVI/Fe(II) with dissolved oxygen (DO) in the solution. In the absence of DO, a similar positive effect of EDDS on Cr(VI) reduction was observed at pH 9.0 as that at pH 5.6–7.0. Additionally, it was found that the EDDS could significantly increase the kinetics of nZVI corrosion in deionized water. These results demonstrate that EDDS could be used effectively as a chelating agent for inhibiting the surface passivation and increasing the effective utilization of nZVI. [ABSTRACT FROM AUTHOR]

An effective ex situ soil remediation technology was developed in this study to remove polycyclic aromatic hydrocarbons (PAHs) and heavy metals in a mixed contaminated site. Ultrasonication (20 kHz, 45 min) combined with methyl-β-cyclodextrin (75 g/L) and S,S-ethylenediaminedisuccinic acid (25 g/L) were efficient in extracting mixed pollutants from the soil. After two successive washing cycles, the removal efficiency of PAHs and heavy metals were approximately 84.5% and 81.3%, respectively. The high removal of metals remarkably reduced soil microtoxicity and thus activated biodegradation activity towards PAHs. Inoculation of PAHs-degrading bacterial strains with nutrients addition further removed 86.8% of residual PAHs in 16 weeks. These results were indicated by the significant increase in the number of PAH degraders and soil enzyme activity. After treatment, the residual levels of individual PAHs and heavy metals could meet Chinese soil quality standard for residential use. The proposed combined cleanup strategy proved to be effective and environmentally friendly for remediation of mixed-contaminated site. [ABSTRACT FROM AUTHOR]