Migration and morphological transformation patterns of heavy metals on sludge cells and extracellular polymeric substances (EPS) under the influence of different treatments.

The impediment of sludge resource utilization stems from the presence of heavy metals within the sludge matrix. To optimize heavy metal removal techniques from undried sludge, it is essential to study the distribution of heavy metals in the sludge flocs structure and the changes in morphology in the sludge cells after different treatments. In this study, the sludge was subjected to chemical treatments using citric acid (CA), EDTA, and saponin, as well as electrokinetic treatment at 2 V/cm.

New-style electrokinetic-adsorption remediation of cadmium-contaminated soil using double-group electrodes coupled with chitosan-activated carbon composite membranes.

Global soil cadmium (Cd(II)) contamination threatens the soil environment, food safety, and human health. Conventional electrokinetic remediation (EKR) and enhancement methods usually operate in strong electric fields, leading to strong side reactions and uneven removal. In this work, to remove Cd(II) from soil effectively in a low-voltage electric field, a new-style electrokinetic-adsorption remediation using double-group electrodes coupled with chitosan-activated carbon composite membranes (DE-EKR-CAC) was developed.

Electrokinetic remediation for the removal of heavy metals in soil: Limitations, solutions and prospection.

Electrokinetic remediation (EKR) technology is a promising method to remove heavy metals from low permeability soil, because it is environmentally friendly, efficient and economical, and can realize in-situ remediation. In this paper, the basic principles and related physical and chemical phenomena of EKR are systematically summarized, and three limiting problems of EKR technology are put forward: the weak ability of dissolving metals, focusing effect, and energy consumption. There are many methods to solve these technical problems, but there is a lack of systematic summary of the causes of problems and solutions.

Synthesis of Hierarchical-Porous Fluorinated Metal-Organic Frameworks with Superior Toluene Adsorption Properties.

Constructing metal-organic frameworks (MOFs) with high volatile organic compounds (VOCs) adsorption capacity and excellent water resistance remain challenging. Herein, a monocarboxylic acid-assisted mixed ligands strategy was designed to synthesize a novel fluorinated MOFs, MIL-53 (Al). The monocarboxylic acid promoted crystallization and produced abundant crystal defects, which increased pore volume.

Recent Advances of Chlorinated Volatile Organic Compounds' Oxidation Catalyzed by Multiple Catalysts: Reasonable Adjustment of Acidity and Redox Properties.

The severe hazard of chlorinated volatile organic compounds (CVOCs) to human health and the natural environment makes their abatement technology a key topic of global environmental research. Due to the existence of Cl, the byproducts of CVOCs in the catalytic combustion process are complex and toxic, and the possible generation of dioxin becomes a potential risk to the environment. Well-qualified CVOC catalysts should process favorable low-temperature catalytic oxidation ability, excellent selectivity, and good resistance to poisoning, which are governed by the reasonable adjustment of acidity and redox properties.

Effects of Three Sludge Products from Co-Treatment of Wastewater on the Soil Properties and Plant Growth of Silty Loam.

Currently, little is known about systematic comparisons of sludge products obtained from different sludge treatment processes in terms of land use. Moreover, it is worth evaluating whether the sludge produced from the co-treatment of industrial wastewater and domestic sewage can be applied to land use. In this study, three sludge products derived from the same municipal sludge-sludge biochar (SSB), dried sludge (DSS), and sludge compost (SSC)-were added to silty loam (SL) at a 20% mass ratio to assess their effects on soil structure, properties, and fertility.

Interface-Enhanced Oxygen Vacancies of CoCuO Catalysts In Situ Grown on Monolithic Cu Foam for VOC Catalytic Oxidation.

The development of highly efficient and stable monolithic catalysts is essential for the removal of volatile organic compounds (VOCs). Copper foam (CF) is a potential ideal carrier for monolithic catalysts, but its low surface area is not conducive to dispersion of active species, thus reducing the interface interaction with active species. Herein, a vertically oriented Cu(OH) nanorod was in situ grown on the CF, which acted as the template and precursor to synthesize CoCu-MOF.

In situ removal of cadmium by short-distance migration under the action of a low-voltage electric field and granular activated carbon.

Cd pollution in soil is a global environmental issue of great concern. The secondary release and low removal rate of Cd are obstacles to the use of adsorption techniques. To develop a sustainable and effective remediation technique, low-voltage direct current (DC) and granular activated carbon (GAC) were applied for in situ Cd removal.

Potential applications of porous organic polymers as adsorbent for the adsorption of volatile organic compounds.

Volatile organic compounds (VOCs) with high toxicity and carcinogenicity are emitted from kinds of industries, which endanger human health and the environment. Adsorption is a promising method for the treatment of VOCs due to its low cost and high efficiency. In recent years, activated carbons, zeolites, and mesoporous materials are widely used to remove VOCs because of their high specific surface area and abundant porosity.

Defective Ultrafine MnO Nanoparticles Confined within a Carbon Matrix for Low-Temperature Oxidation of Volatile Organic Compounds.

The development of catalysts for volatile organic compound (VOC) treatment by catalytic oxidation is of great significance to improve the atmospheric environment. Size-effect and oxygen vacancy engineering are effective strategies for designing high-efficiency heterogeneous catalysts. Herein, we explored the in situ carbon-confinement-oxidation method to synthesize ultrafine MnO nanoparticles with adequately exposed defects.

Synthesis of Silanol-Rich MCM-48 with Mixed Surfactants and Their Application in Acetone Adsorption: Equilibrium, Kinetic, and Thermodynamic Studies.

Mesoporous silica MCM-48 with rich silanol was prepared using polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB) as mixed templates, and the dynamic adsorption performance of acetone was evaluated by testing breakthrough curves. The mixed micelle formed by CTAB and PVP, as well as the hydrogen bond between the carbonyl group of PVP and silanol group affected the condensation process of Si-OH group during the formation of mesoporous structure, resulting in the increase of Si-OH group number on the surface of MCM-48. Compared with MCM-48 synthesized by single template (CTAB), the acetone adsorption capacity of MCM-48 (1:3) synthesized by mixed templates (PVP:CTAB = 1:3) improved by 23.

Enhanced Acetone Oxidation over the CeO/CoO Catalyst Derived from Metal-Organic Frameworks.

A novel CeO/CoO catalyst with a high catalytic activity has been designed and prepared by pyrolysis of metal-organic frameworks, and its catalytic performance was evaluated by the acetone catalytic oxidation reaction. The CoO-M catalyst with at 194 °C was prepared by pyrolysis of the MOF-71 precursor, which was 56 °C lower than that of commercial CoO (250 °C). By the addition of cerium to the MOF-71 precursor, an enhanced CeO/CoO catalyst with at 180 °C was prepared.

Enhanced catalytic performance for volatile organic compound oxidation over in-situ growth of MnOx on CoO nanowire.

Hierarchical CoO@MnOx material has been synthesized by in-suit growth of MnOx on the CoO and applied in catalytic oxidation of volatile organic compounds (VOCs). Results revealed that T of acetone on the CoO@MnOx was 195 °C, which was 36 °C and 32 °C lower than that on the CoO and MnOx/CoO, respectively. The universality experiments demonstrated that T of ethyl acetate and toluene on the CoO@MnOx were 200 °C and 222 °C, respectively.

Synthesis of zeolite SSZ-13 from coal gangue via ultrasonic pretreatment combined with hydrothermal growth method.

SSZ-13 zeolite has been widely used in catalysis and adsorption because of good hydrothermal stability and pore structure. However, long crystallization time is the main challenge limiting its industry application. As increased emissions and ineffective treatment, coal gangue not only occupies land, but also pollutes the waterbody and farmland.

Enhanced catalytic performance for VOCs oxidation on the CoAlO oxides by KMnO doped on facile synthesis.

The MnO was immobilized on the CoAl mixed oxides (CoAlO) derived from hydrotalcites with various anions (CO, Cl, NO and SO) using the hydration and impregnation methods. The CoAlO oxides modified by KMnO were calcined in air at 300 °C to obtain stable oxides, which could be used as catalysts for VOCs (acetone and ethyl acetate) oxidation. CoAlO with CO and 30 h of hydration time (CoAlO-C-Mn-30) exhibited a promising catalytic activity (T = 173 °C for acetone oxidation; T = 175 °C for ethyl acetate), highly superior to CoAlO without KMnO modification.

Application of weak ultrasonic treatment on sludge electro-osmosis dewatering.

Ultrasonic treatment is a good method of facilitating sewage sludge dewatering characteristics. It can also promote the potential of sludge electro-osmosis dewatering (EDW), which is an accepted method of deep dewatering, but the treatment method and optimizing conditions should be determined by performing experiments. In this study, we consider two treating methods: ultrasonic pre-treatment, which uses ultrasonic treatment as sludge pre-treatment before electro-osmosis dehydration, and ultrasonic coupling, which uses ultrasonic and electric fields simultaneously.

Supercritical water pyrolysis of sewage sludge.

Municipal sewage sludge (SS) from wastewater treatment plant containing high water content (>85wt.%), lead to the difficulty of co-combustion with MSW or coal due to the high cost of drying. This study explores an alternative method by supercritical water (SCW) pyrolysis of sewage sludge (SS) in a high pressure reaction vessel.

Drying characteristics of electro-osmosis dewatered sludge.

Electro-osmotic dewatering (EDW) is one of the effective deeply dewatering technologies that is suitable for treating sludge with 55-80% of moisture content. Regarding EDW as the pre-treatment process of drying or incinerating, this article investigated the drying characteristics of electro-osmosis-dewatered sludge, including shear stress test, drying curves analysis, model analysis, and energy balance calculation. After EDW pre-treatment, sludge adhesion was reduced.

DEHP enrichment in the surface microlayer of a small eutrophic lake.

Investigation of di-2-ethylhexyl phthalate (DEHP) in the surface microlayer (SM) and subsurface water (SSW) of a small eutrophic lake was carried out from April to June 2002. Results obtained from the field samples showed that tens to several hundred mug/L of DEHP was found in each sample of SM and SSW, indicating that the lake has been polluted by DEHP. Linear regression analysis showed that concentrations of DEHP were more strongly correlated with sampling temperature than with chlorophyll a concentrations.