Interaction of Pb(II) with microplastic-sediment complexes: Critical effect of surfactant.

In this study, the impact of surfactants on the adsorption behavior of Pb(II) onto microplastics-sediment (MPs-S) complexes was investigated. Firstly, virgin polyamide (VPA) and polyethylene (VPE) were placed in Xiangjiang River sediment for six months to conduct in-situ aging. The results indicated that the biofilm-developed polyamide (BPA) and polyethylene (BPE) formed new oxygen-containing functional groups and different biofilm species.

[A multicenter study of neonatal stroke in Shenzhen, China].

Objectives: To investigate the incidence rate, clinical characteristics, and prognosis of neonatal stroke in Shenzhen, China.

Methods: Led by Shenzhen Children's Hospital, the Shenzhen Neonatal Data Collaboration Network organized 21 institutions to collect 36 cases of neonatal stroke from January 2020 to December 2022. The incidence, clinical characteristics, treatment, and prognosis of neonatal stroke in Shenzhen were analyzed.

Effects of microplastics on microbial community structure and wheatgrass traits in Pb-contaminated riparian sediments under flood-drainage-planting conditions.

The coexistence of microplastics (MPs) and heavy metals in sediments has caused a potential threat to sediment biota. However, differences in the effects of MPs and heavy metals on microbes and plants in sediments under different sediment conditions remain unclear. Hence, we investigated the influence of polyethylene (PE) and polylactic acid (PLA) MPs on microbial community structure, Pb bioavailability, and wheatgrass traits under sequential incubation of sediments (i.

Impact of polyamide microplastics on riparian sediment structures and Cd(II) adsorption: A comparison of natural exposure, dry-wet cycles, and freeze-thaw cycles.

Microplastics (MPs) accumulation in sediments has posed a huge threat to freshwater ecosystems. However, it is still unclear the effect of MPs on riparian sediment structures and contaminant adsorption under different hydrological processes. In this study, three concentrations of polyamide (PA) MPs-treated sediments (0.

Isolation and application of Bacillus thuringiensis LZX01: Efficient membrane biofouling mitigation function and anti-toxicity potential.

Significant progress has been made in mitigating membrane biofouling by microbial quorum quenching (QQ). More efficient and survivable QQ strains need to be discovered. A new strain named Bacillus thuringiensis LZX01 was isolated in this study using a low carbon source concentration "starving" method from a membrane bioreactor (MBR).

Insights into the rapid start-up of an inoculated municipal sludge system: A high-height-to-diameter-ratio airlift inner-circulation partition bioreactor based on CFD analysis.

The utilization of municipal sludge as a seed sludge for initiating the autotrophic nitrogen removal (ANR) process presents a challenge due to the negligible abundance of anaerobic ammonia-oxidizing bacteria (AnAOB). Here, a computational fluid dynamics model was used to simulate sludge volume fraction and sludge particle velocity. A high-height-to-diameter-ratio airlift inner-circulation partition bioreactor (HHAIPBR) was operated for 175 d to enrich AnAOB from municipal sludge, and the performance of the ANR process was investigated.

Intensifying single-stage denitrogen by a dissolved oxygen-differentiated airlift internal circulation reactor under organic matter stress: Nitrogen removal pathways and microbial interactions.

Current research focuses on efficient single-stage nitrogen removal from organic matter wastewater using the partial nitritation-anammox (PNA) process. In this study, we constructed a single-stage partial nitritation-anammox and denitrification (SPNAD) system using a dissolved oxygen-differentiated airlift internal circulation reactor. The system was operated continuously for 364 days at 250 mg/L NH-N.

Insight into the pollution characteristics of road and roof runoff in Changsha, China.

Non-point source pollution from rainwater runoff presents a serious challenge for urban water management in many cities undergoing urbanization and experiencing climate change. To alleviate water resource conflicts in Changsha, China, this study comprehensively evaluated the pollution characteristics and first flush effect (FFE) of runoff from asphalt roads and colored steel plate roofs under seven rainfall events in April-May 2022. The runoff was collected and purified using bioretention ponds.

Swine wastewater treatment using combined up-flow anaerobic sludge blanket and anaerobic membrane bioreactor: Performance and microbial community diversity.

To address the existing economic and environmental issues associated with swine wastewater (SW) treatment, a process combining up-flow anaerobic sludge blanket (UASB) and anaerobic membrane bioreactor (AnMBR) was developed and continuously operated for 137 d. Bioreactor conversion and microbial community dynamics in reactors were analyzed. The UASB-AnMBR process yielded excellent pollutants removal efficiencies of 96% and 63% for chemical oxygen demand (COD) and total phosphorous (TP), respectively.

Investigation of the adsorption behavior of Pb(II) onto natural-aged microplastics as affected by salt ions.

In this study, the adsorption behavior of Pb(II) on natural-aged and virgin microplastics in different electrolyte solutions was investigated. The results demonstrated that natural-aged microplastics exhibited higher adsorption capacity for Pb(II) compared to virgin ones, and the addition of CaCl strongly inhibited the adsorption amount of Pb(II). The adsorption kinetics of Pb(II) adsorption were better fitted by the pseudo-second order model and Elovich equation, and were slowed down greatly at higher ionic strength.

Microplastics as a vehicle of heavy metals in aquatic environments: A review of adsorption factors, mechanisms, and biological effects.

Microplastics (MPs) have recently attracted much attention due to their widespread distribution in the aquatic environment. Microplastics can act as a vector of heavy metals in the aquatic environment, causing a potential threat to aquatic organisms and human health. This review mainly summarized the occurrence of microplastics in the aquatic environment and their interaction with heavy metals.

Role of concentration polarization in cross flow micellar enhanced ultrafiltration of cadmium with low surfactant concentration.

Concentration polarization is an important issue in micellar enhanced ultrafiltration (MEUF) of wastewater containing heavy metal ions at low surfactant concentrations. In this paper, we studied removal of Cd(Ⅱ) by cross flow MEUF at low sodium dodecyl sulfate (SDS) concentration levels, and the role of concentration polarization in flux decline and Cd(Ⅱ) rejection was emphasized. Concentration polarization resistance and SDS concentration near membrane were calculated to characterize concentration polarization.

Roles of surfactants in pressure-driven membrane separation processes: a review.

Surfactants widely exist in various kinds of wastewaters which could be treated by pressure-driven membrane separation (PDMS) techniques. Due to the special characteristics of surfactants, they may affect the performance of membrane filtration. Over the last two decades, there are a number of studies on treating wastewaters containing surfactants by PDMS.

The role of quorum sensing in granular sludge: Impact and future application: A review.

Quorum sensing (QS) is a process widely exist in bacteria, which refers to the cell-cell communication through secretion and sensing the specific chemical signal molecules named autoinducers. This review demonstrated recent research progresses on the specific impacts of signal molecules in the granular sludge reactors, such corresponding exogenous strategies contained the addition of QS signal molecules, QS-related enzymes and bacteria associated with QS process. Accordingly, the correlation between QS signaling molecule content and sludge granulation (including the formation and stability) was assumed, the comprehensive conclusion elucidated that some QS signals (acyl-homoserine lactone and Autoinducer 2) can accelerate the growth of particle diameter, the production of extracellular polymeric substance (EPS), microbial adhesion and change the microbiome structure.

Evaluation of self-cleaning performance of the modified g-CN and GO based PVDF membrane toward oil-in-water separation under visible-light.

Photocatalytic membranes (PMs), coupling of membrane filtration and photocatalysis, have exhibited the potential for application in the wastewater treatment. In this study, we firstly adopted the supramolecular aggregates of melamine (M), cyanuric acid (C), and urea (U) in specific dimethyl sulfoxide (DMSO) as precursors to prepare carbon nitride MCU-CN with high photocatalytic performance, and a kind of novel-designed photocatalytic membrane was prepared via filtrating the mixture of graphene oxide (GO) nanosheets and MCU-CN on PVDF membrane supports, and then crosslinked using glutaraldehyde (GA) to construct a steady coating on the GO/MCU-CN/PVDF membrane. GO/MCU-CN/PVDF composite membrane exhibited higher permeation flux than that of GO/PVDF membrane and exhibited excellent separation performance for oil-in-water emulsion.

Control of indigenous quorum quenching bacteria on membrane biofouling in a short-period MBR.

In this paper, the immobilized quorum quenching (QQ) bacteria - microbial bag was added to a short-period membrane bioreactor (MBR) and its antifouling ability and mechanism were studied by monitoring the changes in transmembrane pressure (TMP), along with the production of N-acyl-homoserine lactones (AHLs), extracellular polymeric substance (EPS) and soluble microbial products (SMP). The QQ bacteria showed efficient mitigation of TMP increase in different membrane fouling stages. In the control MBR group, the TMP reached 43 kPa on the 4th day, while in the experimental group, TMP of QQ-MBR was only 18 kPa at the same time.

Membrane layers intensifying quorum quenching alginate cores and its potential for membrane biofouling control.

Quorum quenching (QQ) has been proved to be an efficient method to mitigate biofouling in membrane bioreactors (MBRs). In this paper, in order to enhance practicability of QQ microcapsules, we prepared three types microcapsules with same alginate cores (SAs). The microcapsules with polyacrylonitrile (PAN) layer showed excellent performance in preventing cell leakage from the microcapsules, increasing service life and improving mechanical strength.

Evaluation of self-cleaning and photocatalytic properties of modified g-CN based PVDF membranes driven by visible light.

Recently, the application of membranes faces a big challenge due to membrane fouling, to alleviate this situation, the hybridization of photocatalysis and membrane filtration has aroused significant attention. In this study, we firstly introduced melamine, cyanuric acid and urea in dimethyl sulfoxide (DMSO) as precursors to fabricated the MCU(DMSO)-CN material with excellent photocatalytic performance, and immobilized it on PVDF membranes by vacuum filtration, subsequently adding polyethylene glycol and glutaraldehyde as crosslinkers from MCU-CN/PVDF membrane. The results demonstrate that with the MCU-CN ratio increasing, the membrane flux was gradually decreased.

A new exploration of health risk assessment quantification from sources of soil heavy metals under different land use.

Heavy metals in the topsoil affected adversely human health through inhalation, ingestion and dermal contact. The health risk assessment, which are quantified from soil heavy metals sources under different land use, can provide an important reference basis for preventing and controlling the soil heavy metals pollution from the source. In this study, simple statistical analysis and Positive Matrix Factorization (PMF) were used to quantify sources of soil heavy metals; then a health risk assessment (HRA) model combined with PMF was proposed to assess quantificationally the human health risk (including non-cancer risk and cancer risk) from sources under residential-land, forest-land and farm land.

Fate of pharmaceuticals during membrane bioreactor treatment: Status and perspectives.

Pharmaceuticals in surface waters and wastewater treatment plants (WWTPs) as emerging pollutants have become a major concern. In comparison with other wastewater treatments, removal of pharmaceuticals in MBR has received much attention. This review presents the source and occurrence of pharmaceuticals in WWTPs influents.

Honeycomb-like carbon nitride through supramolecular preorganization of monomers for high photocatalytic performance under visible light irradiation.

A metal-free modified carbon nitride MCU(DMSO)-CN (3:3:1) with a honeycomb-like morphology was prepared via firstly introducing cyanuric acid and urea into melamine in dimethyl sulfoxide (DMSO) as the precursor for the MCU-CN. A variety of characterization methods, including XRD, XPS, FT-IR, SEM, TEM, UV-vis, photoluminescence (PL), and photocurrent generation, were applied to investigate the structure, morphology, optical, and photoelectrochemical properties of the g-CN and MCU-CN (3:3:1). Rhodamine B (RhB), methylene blue (MB), and bisphenol A (BPA) were selected as target pollutants to evaluate photocatalytic activity of the MCU-CN (3:3:1) under visible light irradiation.

Stable, metal-free, visible-light-driven photocatalyst for efficient removal of pollutants: Mechanism of action.

A low-cost and metal-free semiconductor-based photocatalyst driven by visible light has attracted great interest for water remediation. A relatively larger-surface area carbon nitride consisting of thin nanosheets is synthesized, firstly adopting melamine (M), cyanuric acid (C), urea (U) and dimethyl sulfoxide (DMSO) as the starting materials to form the supramolecular carbon nitride MCU(DMSO)-CN. Physical, chemical, and optical properties of the resulting samples were characterized.

Quorum quenching bacteria encapsulated in PAC-PVA beads for enhanced membrane antifouling properties.

In order to improve the antifouling properties of quorum quenching (QQ) bacteria immobilized beads, the mechanical strength and permeability of QQ beads were modified by adding powdered activated carbon (PAC) based on traditional polyvinyl alcohol (PVA)-boric acid method. Optimal PAC concentration was investigated through measuring the mechanical strength, permeability and N-octanoyl-DLhomoserine lactone (C8-HSL) removal ratio of the PAC-PVA beads. Particularly, the enhanced antifouling effects of the optimal PAC-PVA beads were compared with those of original QQ beads through a membrane filtration experiment under constant pressure.

Biofouling control and sludge properties promotion through quorum quenching in membrane bioreactors at two aeration intensities.

Objective: A modified method was used for cell entrapped beads (CEBs) preparation and two aeration intensities (low and high aeration intensity) was supplied as factors to investigate the change of quorum quenching performance for membrane biofouling in membrane bioreactor (MBR).

Results: Dehydrogenase activity and growth trend of activated sludge were improved at high aeration intensity. Compared with C-MBR (with vacant beads), QQ-MBR (with CEBs) had more stable quorum quenching activity and longer application time at high aeration intensity, in which the proteins and polysaccharides were reduced by 15 and 20%, respectively.

Exploiting extracellular polymeric substances (EPS) controlling strategies for performance enhancement of biological wastewater treatments: An overview.

Extracellular polymeric substances (EPS) are present both outside of the cells and in the interior of microbial aggregates, and account for a main component in microbial aggregates. EPS can influence the properties and functions of microbial aggregates in biological wastewater treatment systems, and specifically EPS are involved in biofilm formation and stability, sludge behaviors as well as sequencing batch reactors (SBRs) granulation whereas they are also responsible for membrane fouling in membrane bioreactors (MBRs). EPS exhibit dual roles in biological wastewater treatments, and hence the control of available EPS can be expected to lead to changes in microbial aggregate properties, thereby improving system performance.