Cadmium phytoremediation potential of Houttuynia cordata: Insights from growth, uptake, and rhizosphere mechanisms.

Cadmium (Cd) pollutes 7.0 % of China's land area. This study examined the potential of Houttuynia cordata for Cd phytoremediation because of its ability to accumulate Cd in its growth matrix.

Degradation and humification of steroidal estrogens in the soil environment: A review.

Emerging pollutants are toxic and harmful chemical substances characterized by environmental persistence, bioaccumulation and biotoxicity, which can harm the ecological environment and even threaten human health. There are four categories of emerging pollutants that are causing widespread concern, namely, persistent organic pollutants, endocrine disruptors, antibiotics, and microplastics. The distribution of emerging pollutants has spatial and temporal heterogeneity, which is influenced by factors such as geographical location, climatic conditions, population density, emission amount, etc.

Phytoextraction and Migration Patterns of Cadmium in Contaminated Soils by .

This study was conducted to identify soil cadmium (Cd) removal pathways and their contribution rates during phytoremediation by , as well as to comprehensively assess its phytoremediation potential. Multilayered soil column tests and farmland-simulating lysimeter tests were conducted to investigate the Cd phytoextraction and migration patterns in topsoil and subsoil simultaneously. The aboveground annual yield of grown in the lysimeter was 206 ton·ha.

[Effectiveness and Mechanisms of Chemical Leaching Combined with Electrokinetic Technology on the Remediation of Heavy Metal Contaminated Soil].

In this study, chemical leaching and electrokinetic technology were used to remediate heavy metal contaminated soil to elucidate its effectiveness and mechanisms. Chemical leaching agents of FeCl, Fe(NO), KCl, KNO, and HCl solutions were selected, and the effects of Fe, K, H, and Cl on four heavy metal (Cd, Pb, Cu, and Zn) removals were compared and analyzed. Then, the influence of the speciation of heavy metals in soil after chemical leaching on the electrokinetic remediation efficiency was studied.

Field experiments to assess the remediation efficiency of metal-contaminated soil by flushing with ferric chloride followed by applying amendments.

The Cd, Cu, Pb, and Zn removal efficiencies achieved by flushing with FeCl were determined in a field experiment using soil contaminated with multiple metals. Soil was first flushed with FeCl and then with FeCl or a mixture of chelators. Flushed soil was amended with lime and organic matter to revitalize the soil, then the soil was used to grow Zea mays and Brassica juncea.

Green remediation of cadmium-contaminated soil by cellulose nanocrystals.

Cellulose nanocrystals (CNC) were used as a novel, green eluent to remediate Cd-contaminated soil in this study. The influence of washing conditions on the removal of Cd, including CNC concentration, pH value, liquid/solid (L/S) ratio, contact time and temperature were investigated. The effect of CNC remediation of Cd-contaminated soil on soil health and the possible remediation mechanism were also explored.

Evaluation of manganese application after soil stabilization to effectively reduce cadmium in rice.

In order to produce safe rice from cadmium (Cd) contaminated soils, a special pot experiment in the field was proposed to facilitate the study of multiple remediation measures. In the field experiments, four treatments were selected for the first half of the year: rice without soil treatment (R); rice with zeolite stabilization (RZ); oilseed rape phytoremediation (OR); and inter-cropping Sedum alfredii and maize phytoremediation (IC). As the early rice with zeolite stabilization still contained elevated Cd, manganese (Mn) fertilizer was added in the late rice with a special pot experiment in the field.

Potential for phytoremediation of nonylphenol from sewage sludge.

Nonylphenol (NP) is considered a major contaminant that must be removed to enable safe and environmentally friendly land application of sewage sludge. Phytoremediation is a technology in which plants are used to remove and/or stabilize organic and inorganic contaminants present in the soil, municipal wastewater, and sewage sludge. In this study, a 391-d large pot experiment was conducted to remove NP from sewage sludge by phytoremediation using Zea mays L.

Cadmium adsorption behavior of porous and reduced graphene oxide and its potential for promoting cadmium migration during soil electrokinetic remediation.

In this study, a porous reduced graphene oxide (PRGO) carbon nanomaterial was successfully obtained by activation of natural graphite with KOH at high temperature and was applied as an auxiliary electrode in soil electrokinetic remediation to investigate the promoting effect on Cd migration. We found that PRGO contained a large amount of oxygen-containing groups (hydroxyl and carboxyl groups) and exhibited high Cd adsorption efficiency at pH values above 4, achieving a maximum adsorption capacity of 434.78 mg/g for Cd.

Aggregation kinetics and mechanisms of silver nanoparticles in simulated pollution water under UV light irradiation.

This paper investigated the effect mechanism of complex components (fulvic acid [FA], sodium dodecylbenzene sulfonate [SDBS], and sodium nitrate [NaNO ]) on the aggregation kinetics of polyvinylpyrrolidone-modified silver nanoparticles (PVP-AgNPs) under UV irradiation. The results showed that FA and NaNO alone did not cause aggregation due to the high steric hindrance and/or electrostatic repulsive forces. In high concentration of SDBS solution (20-50 mM), the stability of PVP-AgNPs was reduced by adsorbing SDBS on nanoparticle surface and replacing their PVP coatings.

Relevance of dissolved organic matter generated from green manuring of Chinese milk vetch in relation to water-soluble cadmium.

Dissolved organic matter (DOM) can become a carrier of soil contaminants. Therefore, an understanding of the evolution and characteristics of DOM produced by Chinese milk vetch during green manuring is crucial. In this study, DOM solutions from 28 days' manuring with three different organic materials were characterized using three-dimensional fluorescence excitation-emission matrix (3D-EEM) with parallel factor (PARAFAC) analysis, and ultraviolet-visible spectroscopy.

Combining potassium chloride leaching with vertical electrokinetics to remediate cadmium-contaminated soils.

This study evaluated the feasibility of combining potassium chloride (KCl) leaching and electrokinetic (EK) treatment for the remediation of cadmium (Cd) and other metals from contaminated soils. KCl leaching was compared at three concentrations (0.2%, 0.

Effect of mixed chelators of EDTA, GLDA, and citric acid on bioavailability of residual heavy metals in soils and soil properties.

Soil washing is an effective technology for the remediation of multi-metal contaminated soils. However, bioavailability of residual heavy metals in soils and soil properties could be changed during washing processes. This study investigated the effects of EDTA, FeCl and mixed chelators (MC) on bioavailability of residual heavy metals in soils and soil biological properties after soil washing.

Using a high biomass plant Pennisetum hydridum to phyto-treat fresh municipal sewage sludge.

The study was carried out to investigate the use of a high biomass plant, Pennisetum hydridum, to treat municipal sewage sludge (MSS). An experiment composed of plots with four treatments, soil, fresh sludge, soil-sludge mixture and phyto-treated sludge, was conducted. It showed that the plant could not survive directly in fresh MSS when cultivated from stem cuttings.

Effect of soil washing with only chelators or combining with ferric chloride on soil heavy metal removal and phytoavailability: Field experiments.

In a field experiment on multi-metal contaminated soil, we investigated the efficiency of Cd, Pb, Zn, and Cu removal by only mixture of chelators (MC) or combining with FeCl3. After washing treatment, a co-cropping system was performed for heavy metals to be extracted by Sedum alfredii and to produce safe food from Zea mays. We analyzed the concentration of heavy metals in groundwater to evaluate the leashing risk of soil washing with FeCl3 and MC.

[Enhanced Phytoextraction of Heavy Metals from Contaminated Soils Using Sedum alfredii Hance with Biodegradable Chelate GLDA].

Chemically enhanced phytoextraction by hyperaccumulator has been proposed as an effective approach to remove heavy metals from contaminated soil. Pot experiment was conducted to investigate the effect of application of the biodegradable chelate GLDA (L glutamic acid N,N-diacetic acid) at different doses or the combination of GLDA with EDTA (ethylenediamine tetraacetic acid) or CIT (citric acid) on the uptake of Cd, Zn and Pb by Sedum alfredii Hance (a Zn and Cd hyperaccumulator). Experimental results showed that GLDA addition to soil significantly increased the concentrations of Cd and Zn in Sedum alfredii Hance and its Cd and Zn phytoextraction compared to the control.

[Continuous remediation of heavy metal contaminated soil by co-cropping system enhanced with chelator].

In order to elucidate the continuous effectiveness of co-cropping system coupling with chelator enhancement in remediating heavy metal contaminated soils and its environmental risk towards underground water, soil lysimeter (0.9 m x 0.9 m x 0.

Phytoremediation of sewage sludge and use of its leachate for crop production.

The land application of sewage sludge has the potential risk of transferring heavy metals to soil or groundwater. The agricultural reuse of sludge leachate could be a cost-effective way to decrease metal contamination. Sludge leachate collected during the phytoremediation of sludge by co-cropping with Sedum alfredii and Zea mays was used for irrigating vegetables in a field experiment.

Cadmium sorption characteristics of soil amendments and its relationship with the cadmium uptake by hyperaccumulator and normal plants in amended soils.

In order to select appropriate amendments for cropping hyperaccumulator or normal plants on contaminated soils and establish the relationship between Cd sorption characteristics of soil amendments and their capacity to reduce Cd uptake by plants, batch sorption experiments with 11 different clay minerals and organic materials and a pot experiment with the same amendments were carried out. The pot experiment was conducted with Sedum alfredii and maize (Zea mays) in a co-cropping system. The results showed that the highest sorption amount was by montmorillonite at 40.

Dissolution of different zinc salts and zn uptake by Sedum alfredii and maize in mono- and co-cropping under hydroponic culture.

Previous soil pot and field experiments demonstrated that co-cropping the hyperaccumulator Sedum alfredii with maize increased Zn phytoextraction by S. alfredii and decreased Zn uptake by maize shoots. This hydroponic experiment was conducted to investigate whether the facilitation of Zn phytoextraction by S.

Fate of heavy metals and major nutrients in a sludge-soil-plant-leachate system during the sludge phyto-treatment process.

Land application of sewage sludge usually leads to increased levels of heavy metals in soil, plants and groundwater. Pre-treatment using plants has been proposed to reduce the contents of heavy metals and water in sludge prior to land application. This study quantified the transfer of Zn, Cd, Pb and major nutrients in a sludge-soil-plant-leachate system during the treatment of sewage sludge.

[Effects of mixed chelators on the leaching of cadmium in contaminated soils under intercropping system].

In order to elucidate the influence of chelators on Cd leaching in contaminated soil, outdoor soil column (100 cm) leaching experiments were conducted using two paddy soils irrigated with Pb-Zn mining wastewater. Soil samples which under intercropping systems were collected from Qingyuan City (acid soil with pH 4.63) and Lechang city (neutral soil with pH 6.

Effect of composting on the removal of semivolatile organic chemicals (SVOCs) from sewage sludge.

In order to investigate the occurrence and removal of semivolatile organic chemicals (SVOCs) in the compost of sewage sludge, three different composting treatments, including manual turned compost (MTC), intermittent aerated compost (IAC), and naturally aerated compost (NAC) were conducted. Thirty SVOCs in composts were Soxhlet-extracted and analyzed by GC/MS. After 56 days of composting, the total concentrations of 16 polycyclic aromatic hydrocarbons (∑PAHs) ranged from 0.

[Metal removal from contaminated soil by co-planting phytoextraction and soil washing].

Combining the different soil remediation technologies can overcome the shortcoming of a single technique, for example, the combination of phyto-extraction with chemical washing can enhance the phytoextraction and build up an effective technology. In a pot experiment, the co-crop of Sedum alfredii and Zea mays was conducted, chemical washing was also applied with different mixtures of chelators (MC). Metals amounts washed by leaching, the uptake of metals by plants and the metals contents remained in soils were determined.