Applying a nanocomposite hydrogel electrode to mitigate electrochemical polarization and focusing effect in electrokinetic remediation of a Cu- and Pb-contaminated loess.

Inappropriate handling of copper (Cu) and lead (Pb)-containing wastewater resulting from metallurgical and smelting industries in Northwest China encourages their migration to surrounding environments. Their accumulation causes damage to liver and kidney function. The electrokinetic (EK) technology is considered to be an alternative to traditional remediation technologies because of its great maneuverability.

Immobilizing lead and copper in aqueous solution using microbial- and enzyme-induced carbonate precipitation.

Inappropriate irrigation could trigger migration of heavy metals into surrounding environments, causing their accumulation and a serious threat to human central nervous system. Traditional site remediation technologies are criticized because they are time-consuming and featured with high risk of secondary pollution. In the past few years, the microbial-induced carbonate precipitation (MICP) is considered as an alternative to traditional technologies due to its easy maneuverability.

Evaluating gas breakthrough pressure and gas permeability in a landfill cover layer for mitigation of hazardous gas emissions.

The construction of an engineered cover layer over landfills is a common method applied to reduce the emission of hazardous gases into the atmosphere. Landfill gas pressures can reach 50 kPa or even higher in some cases, thus posing a serious threat to nearby properties and human safety. As such, the evaluation of gas breakthrough pressure and gas permeability in a landfill cover layer is of great necessity.

Investigating immobilization efficiency of Pb in solution and loess soil using bio-inspired carbonate precipitation.

Lead (Pb) metal accumulation in surrounding environments can cause serious threats to human health, causing liver and kidney function damage. This work explored the potential of applying the MICP technology to remediate Pb-rich water bodies and Pb-contaminated loess soil sites. In the test tube experiments, the Pb immobilization efficiency of above 85% is attained through PbCO and Pb(CO)(OH) precipitation.

Immobilizing copper in loess soil using microbial-induced carbonate precipitation: Insights from test tube experiments and one-dimensional soil columns.

Biomineralization as an alternative to traditional remediation measures has been widely applied to remediate copper (Cu)-contaminated sites due to its environmental-friendly nature. Immobilizing Cu is, however, a challenging task as it inevitably causes inactivation of ureolytic bacteria. In the present work, a series of test tube experiments were conducted to derive the relationships of Cu immobilization efficiency versus pH conditions.

Effect of seepage conditions on the microstructural evolution of loess across north-west China.

Loess features metastable microstructure and is deemed susceptible to chemical contaminant permeation. However, studies on the loess permeability evolution under water and chemical environments are remarkably limited. In this study, the response of the loess to the water and sodium sulfate seepages was analyzed using the temporal relationship of cations concentration, X-ray diffraction and fluorescence (XRD and XRF), mercury intrusion porosimetry (MIP), and scanning electron microscope (SEM) tests.

Effects of the Urease Concentration and Calcium Source on Enzyme-Induced Carbonate Precipitation for Lead Remediation.

Heavy metal contamination during the rapid urbanization process in recent decades has notably impacted our fragile environments and threatens human health. However, traditional remediation approaches are considered time-consuming and costly, and the effect sometimes does not meet the requirements expected. The present study conducted test tube experiments to reproduce enzyme-induced carbonate precipitation applied to lead remediation under the effects of urease concentration and a calcium source.

Effects of bacterial inoculation and calcium source on microbial-induced carbonate precipitation for lead remediation.

Heavy metal contamination has caused serious threats to surrounding fragile environments and human health. While the novel microbial-induced carbonate precipitation (MICP) technology in the recent years has been proven effective in improving material mechanical and durability properties, the mechanisms remedying heavy metal contamination still remain unclear. In this study, the potential of applying the MICP technology to the lead remediation under the effects of urease activity and calcium source was explored.

Revealing the Enhancement and Degradation Mechanisms Affecting the Performance of Carbonate Precipitation in EICP Process.

Given that acid-rich rainfall can cause serious damage to heritage buildings in NW China and subsequently accelerate their aging problem, countermeasures to protect their integrity and also to preserve the continuity of Chinese culture are in pressing need. Enzyme-induced carbonate precipitation (EICP) that modifies the mechanical properties of the soil through enhancing the interparticle bonds by the precipitated crystals and the formation of other carbonate minerals is under a spotlight in recent years. EICP is considered as an alternative to the microbial-induced carbonate precipitation (MICP) because cultivating soil microbes are considered to be challenging in field applications.