Insights into the conversion of dissolved organic phosphorus favors algal bloom, arsenate biotransformation and microcystins release of Microcystis aeruginosa

Little information is available on influences of the conversion of dissolved organic phosphorus(DOP) to inorganic phosphorus(IP) on algal growth and subsequent behaviors of arsenate(As(V)) in Microcystis aeruginosa(M. aeruginosa). In this study, the influences factors on the conversion of three typical DOP types including adenosine-5-triphosphate disodium salt(ATP), β-glycerophosphate sodium(βP) and D-glucose-6-phosphate disodium salt(GP)were investigated under different extracellular polymeric secretions(EPS) ratios from M.aeruginosa, and As(V) levels. Thus, algal growth, As(V) biotransformation and microcystins(MCs) release of M. aeruginosa were explored in the different converted DOP conditions compared with IP. Results showed that the three DOP to IP without EPS addition became in favor of algal growth during their conversion. Compared with IP, M. aeruginosa growth was thus facilitated in the three converted DOP conditions, subsequently resulting in potential algal bloom particularly at arsenic(As) contaminated water environment. Additionally, DOP after conversion could inhibit As accumulation in M. aeruginosa, thus intracellular As accumulation was lower in the converted DOP conditions than that in IP condition. As(V) biotransformation and MCs release in M. aeruginosa was impacted by different converted DOP with their different types. Specifically, DMA concentrations in media and As(III) ratios in algal cells were promoted in converted βP condition, indicating that the observed dissolved organic compositions from βP conversion could enhance As(V) reduction in M. aeruginosa and then accelerate DMA release. The obtained findings can provide better understanding of cyanobacteria blooms and As biotransformation in different DOP as the main phosphorus source.

The frontier of microplastics and nanoplastics: Soil health and carbon neutrality

Microplastics and nanoplastics(MNPs)in soil have drawn increasing concerns about their potential threats to soil ecosystems due to their ubiquitous occurrence and persistence.The interactions of MNPs with soil components,microbial community,plants,and fauna determine their impacts on soil biogeochemical processes and food security.However,they are not largely explored.Further research is also needed to develop reliable and standardized techniques and methods to characterize the relevant MNPs interacting with different types of soil ecosystems and to deeply examine their impacts on soil health,food security,and climate changes.In addition,mitigation protocols and regulation guidelines need to be developed.New findings will provide scientific and technological support for the understanding and management of soil health and carbon neutrality as influenced by MNPs.

Synthesis of a novel ternary HA/Fe-Mn oxides-loaded biochar composite and its application in cadmium(Ⅱ) and arsenic(Ⅴ) adsorption

Cadmium (Cd) and arsenic (As) are two of the most toxic elements.However,the chemical behaviors of these two elements are different,making it challenging to utilize a single adsorbent with high adsorption capacity for both Cd(Ⅱ) and As(Ⅴ) removal.To solve this problem,we synthesized HA/Fe-Mn oxides-loaded biochar (HFMB),a novel ternary material,to perform this task,wherein scanning electron microscopy (SEM) combined with EDS (SEM-EDS) was used to characterize its morphological and physicochemical properties.The maximum adsorption capacity of HFMB was 67.11 mg/g for Cd(Ⅱ) and 35.59 mg/g for As(Ⅴ),which is much higher compared to pristine biochar (11.06 mg/g,0 mg/g for Cd(Ⅱ) and As(Ⅴ),respectively).The adsorption characteristics were investigated by adsorption kinetics and the effects of the ionic strength and pH of solutions.X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR) revealed that chelation and deposition were the adsorption mechanisms that bound Cd(Ⅱ) to HFMB,while ligand exchange was the adsorption mechanism that bound As(Ⅴ).

Thallium contamination in agricultural soils and associated potential remediation via biochar utilization

Thallium(Tl)is an extremely harmful metal that is substantially distributed in the environment.It can threaten human health via consumption of food potentially derived from Tl-contaminated agricultural production.Little information is available on how to utilize biochar to remediate Tl contamination in agricultural soils.More efforts are urgently needed to be devoted to developing effective techniques to empower biochar with high selectivity of Tl in agricultural soils.In this review,we provided comprehensive information on Tl contamination in agricultural soils.We also discussed recent developments and assessed the current status of biochar applications.We briefly reviewed the bridge between biochar preparation technology and utilization wherein further developments can exhibit potential in terms of Tl remediation.Hence,biochar is expected to exhibit excellent Tl remediation performance in contaminated agricultural soils with promising application prospects.The obtained knowledge provides further insights into the remediation of Tl contamination in agricultural soils.

Insights into thallium adsorption onto the soil,bamboo-derived biochar,and biochar amended soil in Pomelo orchard

Little information is available on thallium(Tl)adsorption onto biochar amended soil for a relatively long term.In this study,bamboo-derived biochar(BDB),soil in pomelo orchard(SP),and biochar amended soil in pomelo orchard(BSP)were thus used to evaluate the potential remediation of thallium(Tl)using batch-adsorption techniques.Furthermore,we characterized the above-mentioned sorbents’properties related to Tl adsorption to understand Tl’s adsorption mechanisms.The results showed that BDB,SP,and BSP achieved equilibrium adsorption capacity of 96.9,95.43,and 96.76%,respectively,within the initial 15 min.This means that compared to other sorbents,BSP exhibited an efficient sorbent for Tl remediation even when applied in the agricultural field for one year.Multi-layer adsorption played a dominant role in the adsorption of Tl,which was supported by the suitability of Freundlich model for describing the adsorption behavior of Tl onto the selected sorbents.In addition,the pseudo-second kinetic order models strongly fitted Tl’s adsorption onto BDB,SP,and BSP,indicating that the process was accompanied by chemical adsorption.Observed on the surface of BDB by a Fourier Transform Infrared Spectrometer(FTIR)and an X-ray photoelectron spectroscopy(XPS),the presence of O-H groups and PO_(4)^(3−)might promote chemical adsorption of Tl onto BDB.Overall,these findings can provide insights into comprehensively developed bamboo-derived biochar technology to remediate Tl contamination in agricultural soils.