Competitive adsorption and desorption of three antibiotics in distinct soil aggregate size fractions.

Multiple antibiotics that are used in veterinary medicine coexist in soils, but their interaction and the effects on adsorption and desorption in soils have not been extensively studied. In this study, using batch experiments, we evaluated the adsorption and desorption of sulfadiazine (SDZ), tetracycline (TC), and norfloxacin (NFX) using four different soil aggregate size fractions and discovered that: (1) TC had the highest adsorption (76-98 %) and the lowest desorption in each tested system, whereas SDZ showed opposite adsorption and desorption ability, (2) the highest adsorption and the lowest desorption of all three tested antibiotics were observed with soil macroaggregates (250-2000 µm) in all the cases; in contrast, opposite adsorption and desorption ability were observed for soil clay (<53 µm), and (3) adsorption of each antibiotic was in the following order: single system (71-89 %) > binary system (56-84 %) > ternary system (50-78 %); however, desorption were in the reverse order. The Freundlich equation fitting and Brunauer-Emmett-Teller (BET) analysis further demonstrated that the adsorption competition between the tested antibiotics depended mainly on the specific surface area of each soil aggregate size fractions and its chemical properties. In conclusion, soil macroaggregates play a key role in the retention of antibiotics in soils, and the coexistence of multiple antibiotics greatly increases leaching risk.

Recovery of microbial community in strongly alkaline bauxite residues after amending biomass residue.

The aim of this study was to characterize the effects of cornstalk biomass amendments on microbial communities in bauxite residues (BRs) by phylogenetic analysis. Improvements in soil geochemical, physical, and biological properties were assessed to identify the major factors controlling microbial community development in BRs. After one year of incubation, the salinity and structure of the amended BRs had gradually improved, with pH dropping from 11.39 to 9.89, the exchangeable sodium percentage (ESP) dropping from 86.3% to 35.2%, and the mean weight diameter (MWD) rising from 0.12 mm to 0.38 mm. Further analysis of community level physiological profiles (CLPP) showed that the microbial utilization of different carbohydrates had shifted significantly, in addition to increases in the diversity index H' (0.7-7.34), U (2.16-3.14), and the average well color development (0.059-1.08). Over the one-year outside incubation, the dominant fungal phyla in the BRs had shifted gradually from Ascomycota (85.64%) to Ascomycota (52.07%) and Basidiomycota (35.53%), while the dominant bacterial phyla had shifted from Actinobacteria (38.47%), Proteobacteria (21.39%), and Gemmatimonadetes (12.72%) to Actinobacteria (14.87%), Proteobacteria (23.53%), and Acidobacteria (14.37%). Despite these shifts, microbial diversity remained lower in the amended BRs than in the natural soil. Further redundancy analysis indicated that pH was the major factor driving shifts in the bacterial community, while aggregates were the major factor driving shifts in the fungal community. This study demonstrated that amendment with cornstalk biomass shifted the microbial community in the BRs from halophilic groups to acidogenic groups by improving the soil environmental conditions.

Effect of Soil Solution Properties and Cu2+ Co-Existence on the Adsorption of Sulfadiazine onto Paddy Soil.

Paddy soils are globally distributed and saturated with water long term, which is different from most terrestrial ecosystems. To better understand the environmental risks of antibiotics in paddy soils, this study chose sulfadiazine (SDZ) as a typical antibiotic. We investigated its adsorption behavior and the influence of soil solution properties, such as pH conditions, dissolved organic carbon (DOC), ionic concentrations (IC), and the co-existence of Cu2+. The results indicated that (1) changes in soil solution pH and IC lower the adsorption of SDZ in paddy soils. (2) Increase of DOC facilitated the adsorption of SDZ in paddy soils. (3) Cu2+ co-existence increased the adsorption of SDZ on organic components, but decreased the adsorption capacity of clay soil for SDZ. (4) Further FTIR and SEM analyses indicated that complexation may not be the only form of Cu2+ and SDZ co-adsorption in paddy soils. Based on the above results, it can be concluded that soil solution properties and co-existent cations determine the sorption behavior of SDZ in paddy soils.

The Synthesis of Porous Na3 V2 (PO4 )3 for Sodium-Ion Storage.

Na3 V2 (PO4 )3 (NVP) has been regarded as a potential cathode material for sodium-ion batteries (SIBs) due to its excellent structural stability and rapid Na+ conductivity. However, its electrochemical performances are restricted by the large bulk structure and poor electronic conductivity. The construction of porous NVP materials is a powerful method to improve the electrochemical properties. This concept aims to provide an overview of recent progress of porous NVP materials for SIBs. Herein, the synthetic strategies and formation mechanisms of porous NVP materials as well as the relationship between the porous structures and electrochemical performances of NVP materials are reviewed. Furthermore, the challenges and prospects for the preparation of porous NVP materials in this field are outlined.

Activating Old Materials with New Architecture: Boosting Performance of Perovskite Solar Cells with H2O-Assisted Hierarchical Electron Transporting Layers.

The breakthrough of organometal halide perovskite solar cells (PSCs) based on mesostructured composites is regarded as a viable member of next generation photovoltaics. In high efficiency PSCs, it is crucial to finely optimize the charge dynamics and optical properties matching between the perovskites and electron transporting materials to relax the trade-off between the optical and electrical requirements. Here, a simple antipolar route with H2O as the additive is proposed to prepare hierarchical electron transporting layers to boost the efficiency of dopant-free PSCs. The photovoltaic performance of the PSCs is enhanced owing to increased light-scattering, improved Ostwald ripening, and photo-generated electron extraction. Optimization of the H2O addition enables a valid power conversion efficiency of 19.9% (reverse scan: 20.02%) to be achieved. The device can retain more than 90% of its initial performance after storage in air more than 30 days. These results are inspiring in that they present that a mesoporous transporting layer could be easily re-constructed to hierarchical architecture by the antipolar method to further improve the performance of PSCs.

Synthesis of simple, low cost and benign sol-gel Cu2In x Zn1-x SnS4 alloy thin films: influence of different rapid thermal annealing conditions and their photovoltaic solar cells.

Cu2In x Zn1-x SnS4 (x = 0.4) alloy thin films were synthesized on soda lime glass (SLG) substrate by a simple low-cost sol-gel method followed by a rapid annealing technique. The influence of sulfurization temperature and sulfurization time on the structure, morphology, optical and electrical properties of Cu2In x Zn1-x SnS4 thin films was investigated in detail. The XRD and Raman results indicated that the crystalline quality of the Cu2In x Zn1-x SnS4 alloy thin films was improved, accompanied by metal deficiency, particularly tin loss with increasing the sulfurization temperature and sulfurization time. From absorption spectra it is found that the band gaps of all Cu2In x Zn1-x SnS4 films are smaller than that (1.5 eV) of the pure CZTS film due to In doping, and the band gap of the Cu2In x Zn1-x SnS4 films can be tuned in the range of 1.38 to 1.19 eV by adjusting the sulfurization temperature and sulfurization time. Hall measurement results showed that all Cu2In x Zn1-x SnS4 alloy thin films showed p-type conductivity characteristics, the hole concentration decreased and the mobility increased with the increase of sulfurization temperature and sulfurization time, which is attributed to the improvement of the crystalline quality and the reduction of grain boundaries. Finally, the Cu2In x Zn1-x SnS4 film possessing the best p-type conductivity with a hole concentration of 9.06 × 1016 cm-3 and a mobility of 3.35 cm2 V-1 s-1 was obtained at optimized sulfurization condition of 580 °C for 60 min. The solar cell using Cu2In x Zn1-x SnS4 as the absorber obtained at the optimized sulfurization conditions of 580 °C for 60 min demonstrates a power conversion efficiency of 2.89%. We observed an increment in open circuit voltage by 90 mV. This work shows the promising role of In in overcoming the low V oc issue in Cu-kesterite thin film solar cells.