Degradation of polyamide nanofiltration membranes by free chlorine and halide ions: Kinetics, mechanisms, and implications.

The kinetics of polyamide membrane degradation by free chlorine and halide ions (Br and Cl) were innovatively evaluated based on physicochemical properties and filtration performance, using water/solute permeability coefficient in addition to bromide incorporation as important indicators. The reaction rate constants for the reduced water and HBO permeability coefficient were 1-2 orders of magnitude higher at 0-1 h than 1-10 h. N-bromination and bromination-promoted hydrolysis are dominant degradation mechanisms at 0-1 h (reflected by the breakage of hydrogen bond, the increased Ca binding content, and the increased charge density), and ring-bromination further occurs at 1-10 h (reflected by the disappearance or weakening of aromatic amide band and the nearly constant hydrogen bond).

Surfactant enhanced persulfate system for the synergistic oxidation and reduction of mixed chlorinated hydrocarbons.

Surfactant-enhanced in-situ chemical oxidation (S-ISCO) is widely applied in soil and groundwater remediation. However, the role of surfactants in the reactive species (RSs) transformation remains inadequately explored. This work introduced nonionic surfactant Tween-80 (TW-80) into a nano zero-valent iron (nZVI) activated persulfate (PS) system.

Risk assessment of lead and cadmium leaching from solidified/stabilized MSWI fly ash under long-term landfill simulation test.

The long-term effectiveness concern of municipal solid waste incineration (MSWI) fly ash (FA) disposal has been placed more emphatic recently, however, few studies worked on the control of leaching risk of heavy metals under the long-term stability. In this study, the leaching properties and risk assessment of two representative solidified/stabilized (S/S) FA wastes, i.e.

Detection of formic acid and acetic acid gases by a QCM sensor coated with an acidified multi-walled carbon nanotube membrane.

In this paper, the acidified multi-walled carbon nanotubes (MWCNTs) film was coated on the quartz crystal microbalance (QCM) to prepare a high-performance sensor for the real-time detection of organic acid gases. The material characteristics of the thin films were analysed by field emission scanning electro microscopy (FESEM), Raman spectra and X-ray photoelectron spectroscopy (XPS). The organic acid vapours' sensing results indicated that acidized-MWCNTs thin film exhibited good frequency response, repeatability, reversibility and stability.

Degradation of Polyamide Nanofiltration Membranes by Bromine: Changes of Physiochemical Properties and Filtration Performance.

The potential coexistence and interaction of bromine and polyamide membranes during membrane-based water treatment prompts us to investigate the effect of bromine on membrane performance. For fully aromatic polyamide membrane NF90 exposed under a mild bromination condition (10 mg/L), bromine incorporation resulted in more negatively charged (-13 vs -25 mV) and hydrophobic (55.2 vs 58.

Ecotoxicity assessment of sodium dimethyldithiocarbamate and its micro-sized metal chelates in Caenorhabditis elegans.

Sodium dimethyldithiocarbamate (SDDC) is a widely used heavy metal chelating agent in harmless treatment of wastewater and hazardous waste, but SDDC and its heavy metal chelates may leak into the environment and bring potential ecological risks. In this study, the model organism Caenorhabditis elegans was used to evaluate the toxic effect of SDDC and its heavy metal Cu, Pb chelates. Multiple endpoints were investigated by subacute exposure to SDDC (0.

Suspended anode-type microbial fuel cells for enhanced electricity generation.

Electricity generation in microbial fuel cells can be restricted by a few factors, such as the effective area of the anode for biofilm attachment, diffusion limitation of substrates and internal resistance. In this paper, a suspended anode (carbon-based felt granule)-type microbial fuel cell was developed to make full use of the volume of the anode chamber and provide a larger surface area of the anode for the growth of exoelectrogenic bacteria. The current collector was rotated in the anodic chamber to contact with the suspended granules intermittently and achieve better mixing.

Enhanced solidification/stabilization of lead in MSWI fly ash treatment and disposal by gelatinized sticky rice.

Recently, innocent treatment of heavy metals in hazardous waste has become a hot topic in China. In particular, lead (Pb) as a typical heavy metal, is one of the easiest leaching heavy metal elements for municipal solid waste incineration (MSWI) fly ash. In this paper, different dosages of gelatinized sticky rice (SR) as green additives were added into the mixture of MSWI fly ash (FA) and ordinary Portland cement (OPC) to solidify/stabilize Pb in an attempt to optimize cement solidification.

Decrease of dissolved sulfide in sewage by powdered natural magnetite and hematite.

Unlabelled: Natural magnetite and hematite were explored to decrease sulfide in sewage, compared with iron salts (FeCl and FeSO). A particle size of magnetite and hematite ranging from 45 to 60μm was used. The results showed that 40mgL of powdered magnetite and hematite addition decreased the sulfide in sewage by 79%and 70%, respectively.

Anodic concentration loss and impedance characteristics in rotating disk electrode microbial fuel cells.

A rotating disk electrode (RDE) was used to investigate the concentration loss and impedance characteristics of anodic biofilms in microbial fuel cells (MFCs). Amperometric time-current analysis revealed that at the rotation rate of 480 rpm, a maximum current density of 168 µA cm(-2) can be achieved, which was 22.2 % higher than when there was no rotation.

Biological capacitance studies of anodes in microbial fuel cells using electrochemical impedance spectroscopy.

It is known that cell potential increases while anode resistance decreases during the start-up of microbial fuel cells (MFCs). Biological capacitance, defined as the apparent capacitance attributed to biological activity including biofilm production, plays a role in this phenomenon. In this research, electrochemical impedance spectroscopy was employed to study anode capacitance and resistance during the start-up period of MFCs so that the role of biological capacitance was revealed in electricity generation by MFCs.

Effect of the chemical oxidation demand to sulfide ratio on sulfide oxidation in microbial fuel cells treating sulfide-rich wastewater.

This work focused on studying the effect of the chemical oxidation demand to sulfide ratio (COD/S) on power generation and sulfide oxidation in microbial fuel cells treating sulfide-rich wastewater containing organic contaminants. The maximum power density achieved was 20 +/- 1 W m(-3) V(Anode) and the C(oulombic) yield was 20 +/- 2%. The COD/S ofinfluent played an important role in elemental sulfur and sulfate production because of competition between acetate oxidation and element sulfur oxidation to sulfate in the anode.

Improvement of biological total phosphorus release and uptake by low electrical current application in lab-scale bio-electrochemical reactors.

The overall process enhancement by different electrical current application on the biological phosphorus release and uptake have been investigated. Five reactors were constructed for three experiments and activated sludge was used as inoculums. In Exp.