Methods for controlling heavy metals in environmental soils based on artificial neural networks.

The problem of heavy metal pollution in soil has become a global environmental problem, and it is very important to predict and manage the heavy metals in the environmental soil in a timely manner. The changes in heavy metal content in soil have characteristics such as nonlinearity and large delay, making it difficult to predict heavy metals in soil using traditional methods. Traditional prediction methods are complex and cumbersome, which can lead to longer treatment time and easy secondary pollution.

Dissolved organic matter released from rice straw and straw biochar: Contrasting molecular composition and lead binding behaviors.

It remains debatable whether carbonized straw reapplying is a better solution than direct straw reapplying. Comparison of the characteristics and complexation behaviors of dissolved organic matter (DOM) derived from straw (ST) and biochar (BC) may offer new insights, but little current information exists. Herein, DOM samples were characterized by Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), revealing that the molecular weight and condensed aromatic components of BCDOM (457.

Binding characteristics of cadmium and zinc onto soil organic matter in different water managements and rhizosphere environments.

Soil organic matter (SOM) could immobilize most of metals, but it could promote the migration of a small part of metals in special environments. Heavy rainfall and drought makes wetlands affected by the alternation of drought and flood, altering the mobility of metals. Few studies have been conducted on the changes of binding characteristics of metals onto SOM which derived from different water conditions and rhizospheric environments.

In situ investigation of intrinsic relationship between protonation behavior and HA characteristics in sediments.

Proton-binding study of humic acid (HA) is critical for describing and modeling the binding mechanism of HA with heavy metals. However, little is known about the intrinsic relationship between protonation behavior and HA characteristics, especially in sediments. In this study, HA was extracted from sediments and combination of spectrographic titration with parallel factor analysis, Gaussian fitting model and two-dimensional correlation spectroscopy analysis was developed as a novel in-situ tool.

Spectroscopic study of the effects of dissolved organic matter compositional changes on availability of cadmium in paddy soil under different water management practices.

It is well established that water management can influence the availability of Cd in paddy soil but the role of dissolved organic matter (DOM) characteristics in this process is still unclear. Here, we measured and compared the DOM quantity and quality between flooded and wetted treatments by spectroscopic and chemometric analysis and applied correlation analysis to relate DOM characteristics with availability concentrations of Cd. Ultraviolet-visible showed that aromaticity and hydrophobicity of DOM significantly decreased with time in wetted paddy soil (p < 0.

Passivating effect of dehydrated sludge and sepiolite on arsenic contaminated soil.

Exploring an efficient and economical method to remove arsenic from soil is of great practical significance but there were few studies on the combined use of sepiolite and dehydrated sludge as a repair agent to passivate heavy metals. Through soil passivation experiments, arsenic sequential extractions, and analysis of basic physicochemical properties of contaminated soils and repair agents, this study was to explore the applicability of dehydrated sludge-sepiolite compound repair agents and dehydrated sludge individual repair agents to passivate soil arsenic and its passivating effect. After passivation experiment, the best remediation period was 1-10 days.

Application potential of biochar in environment: Insight from degradation of biochar-derived DOM and complexation of DOM with heavy metals.

Biochar-derived dissolved organic matter (DOM) is important for determining the application potential of biochar in soil remediation. However, little is known about the degradation behavior of biochar-derived DOM and its interaction with heavy metals. Here, incubation experiments combined with quenching titration experiments, which analyzed by spectroscopic technology and chemometric method, were conducted to reveal such behaviors and mechanisms.

Investigating organic matter properties affecting the binding behavior of heavy metals in the rhizosphere of wetlands.

Soil organic matter (SOM) is a crucial factor affecting the immobilization of heavy metal in wetlands. Recent studies have shown that the rhizosphere SOM has great ability to immobilize heavy metals. However, there existed few works on studying molecular characteristics of SOM to explore the mechanisms.

Remediation of multiple heavy metal-contaminated soil through the combination of soil washing and in situ immobilization.

The remediation of heavy metal-contaminated soils is a great challenge for global environmental sciences and engineering. To control the ecological risks of heavy metal-contaminated soil more effectively, the present study focused on the combination of soil washing (with FeCl) and in situ immobilization (with lime, biochar, and black carbon). The results showed that the removal rate of Cd, Pb, Zn, and Cu was 62.

The complexation of rhizosphere and nonrhizosphere soil organic matter with chromium: Using elemental analysis combined with FTIR spectroscopy.

Complexation is a main mechanism controlling the reactions between soil organic matter (SOM) and heavy metals, which still have not been fully understood up to date. The objective of this study was to compare the SOM composition of nonrhizosphere and rhizosphere in low Cr treatment with that in high Cr treatment and to find out how metal concentrations affect the complexation with SOM. The results revealed that both the hydroxyl and the carboxyl were significantly different under different Cr treatment groups.

Effects of Fe(III)-fulvic acid on Cu removal via adsorption versus coprecipitation.

This study compared the sorption and extractability of Cu following adsorption (SOR) and coprecipitation(CPT). The effect of solution pH, Fe: organic carbon (OC) ratios and fulvic acid (FA) on the combined removal of Cu was investigated in the batch tests using Fe(III) precipitates as a sorbent. Transmission electron microscope (TEM) images demonstrated that the coexisting FA reduced the particle size of ferrihydrites as expected.

Investigating binding characteristics of cadmium and copper to DOM derived from compost and rice straw using EEM-PARAFAC combined with two-dimensional FTIR correlation analyses.

The binding of Cd and Cu to dissolved organic matter (DOM) derived from compost (CP) and rice straw (ST) was studied through an approach combining parallel factor (PARAFAC) analysis and two-dimensional correlation spectroscopy (2DCOS). Both humic-like and protein-like substances have been observed in CP and ST. Comparing with the Cu, Cd exhibited a lower affinity to DOM, and the quenching curve of Cd failed to be fitted by the Ryan and Weber Model, indicating that the environmental risk caused by applying CP or ST to Cd-polluted soil should be considered.

Effect of land use pattern change from paddy soil to vegetable soil on the adsorption-desorption of cadmium by soil aggregates.

The influence of land use change from paddy soil to vegetable soil on the adsorption-desorption behavior of Cd in soil aggregates and the variation in soil properties were investigated. The vegetable soil was characterized by lower pH, organic matter content, cation exchange capacity (CEC), free iron oxides, manganese oxides, and catalase activity and higher urease activity compared with the paddy soil. In the isothermal adsorption and desorption experiments, the adsorption characteristics of Cd of the two soils could be well described by Langmuir and Freundlich equations.

Synthesis, characterization and anti-proliferative activity of heterocyclic hypervalent organoantimony compounds.

Three heterocyclic hypervalent organoantimony chlorides RN(CH2C6H4)2SbCl (2a R = t-Bu, 2b R = Cy, 2c R = Ph) and their chalcogenide derivatives [RN(CH2C6H4)2Sb]2O (3a R = t-Bu, 3b R = Cy, 3c R = Ph) were synthesized and characterized by techniques such as (1)H NMR, (13)C NMR, X-ray diffraction, and elemental analysis. It is found that the anti-proliferative activity detected over these compounds can be attributed to the coordination bond between the antimony and nitrogen atoms of these compounds. Moreover, a preliminary study on mechanistic action suggests that the inhibition effect is ascribable to cell cycle arrest and cell apoptosis.