A Bio-Inspired Drag Reduction Method of Bionic Fish Skin Mucus Structure.

Efforts to enhance the speed and reduce the energy consumption of underwater vehicles have led to the proposal of a novel mucus release structure inspired by the secretion of mucus cells on fish skin. This structure features interconnected microgrooves with excellent flexibility for adjusting to different states, effectively reducing drag through mucus release. Numerical analysis of the drag reduction performance of the mucous-releasing micro-pore structure was conducted using ANSYS Fluent 19.2 software. This structure is capable of reducing the velocity gradient near the wall and, owing to the presence of micro-pore structures, decreasing the overall compressed area, thereby achieving drag reduction effects. The experimental results revealed a drag reduction effect of 20.56% when the structure was bent at an angle of 120°. The drag reduction varied under different attitudes such as tension and compression. This mucus release structure achieves reusability through a direct mucous injection process. This research provides valuable insights for the drag reduction study of underwater vehicles, such as ships and submarines, laying a foundation for advancing the development and applications of this field in the future.

A bio-inspired two-stage bionic drag reduction method.

Reducing the surface resistance of underwater vehicles plays an important role in improving cruising speed and cruising mileage. The epidermis of loaches is not only covered with a layer of scale structure but also secretes mucus tissue with a lubricating effect, which makes loaches swim rapidly in muddy water. Study the morphology and structure of the skin of loach and establish a two-stage biomimetic drag reduction model. Adjust the different structural parameters of the model and select the parameters with the best drag reduction rate for the modeling design. The numerical simulation results show that the optimal drag reduction rate of the two-stage drag reduction structure is greater than 21%. In the flow channel test experiment, the drag reduction rate is slightly lower than the simulation results. Numerical simulation and experimental data show that the underwater drag reduction function can be realized by simulating the microstructure of loach skin. Finally, analyze the velocity gradient, vortices, etc., and search for the drag reduction mechanism. The simulation design of the microstructure of the loach skin can increase the thickness of the boundary layer, promote the vortex structure near the wall surface, change the flow mode of the solid-liquid interface, and reduce the wall resistance. At the same time, the drag reduction model provides key technical support for the practical application of reducing surface resistance, such as in underwater vehicles.

Preserved mucosa unroofing facilitated closure of a large gastric defect after endoscopic full-thickness resection.

A 58-year-old woman was found to have a submucosal bulging lesion in the anterior wall of the gastric fundus during a screening esophagogastroscopy. Endosonographic evaluation revealed it to be a 3.1×2.5cm, hypoechoic mass originating from muscularis propria (MP). Endoscopic full-thickness resection (EFR) was attempted. After submucosal injection, a four-fifth circumferential mucosal incision was made around the lesion. Submucosal dissection was performed to unroof the overlying mucosa, which was preserved via the remaining one-fifth circumferential mucosal edge. Thus a mucosal flap was created and turned aside to expose the mass. En bloc resection of the lesion resulted in a 3.5*3.0cm full-thickness defect . The mucosal flap was flipped back and the defect was almost fully covered. Therefore, closure of the defect was accomplished by simply clipping the two edges of the initially incised mucosa. The patient was discharged 2 days later without discomfort. Histopathology confirmed a gastrointestinal stromal tumor (GIST), prognostic group 1.

Photothermal Synergistic Catalysis over Defective Zn3In2S6 for CO2 Fixation.

Carbon dioxide (CO2) cycloaddition not only produces highly valued cyclic carbonate but also utilizes CO2 as C1 resources with 100% atomic efficiency. However, traditional catalytic routes still suffer from inferior catalytic efficiency and harsh reaction conditions. Developing multienergy-field catalytic technology with expected efficiency offers great opportunity for satisfied yield under mild conditions. Herein, Zn3In2S6 with sulfur vacancies (Sv) was fabricated with the assistance of cetyltrimethylammonium bromide (CTAB), which is further employed for photothermally driven CO2 cycloaddition first. Photoluminescence spectroscopy and photoelectrochemical characterization demonstrated its superior separation kinetics of photoinduced carriers induced by defect engineering. The temperature-programmed desorption (TPD) technique indicated its excellent Lewis acidity-basicity characters. Due to the combination of above merits from photocatalysis and thermal catalysis, defective Zn3In2S6-Sv achieved a yield as high as 73.2% for cyclic carbonate at 80 °C under blue LED illumination within 2 h (apparent quantum yield of 0.468% under illumination of 380 nm monochromatic light at 36 mW·cm-2), which is 2.9, 2.0, and 6.9 times higher than that in dark conditions and those of pristine Zn3In2S6 and industrial representative tetrabutylammonium bromide (TBAB) thermal-catalysis process under the same conditions, respectively. The synergistic reaction path of photocatalysis and thermal catalysis was discriminated by theoretical calculation. This work provides new insights into the photothermal synergistic catalysis CO2 cycloaddition with defective ternary metal sulfides.

Electrochemical mechanism of synchronous ammonia and nitrate removal based on multi-objective optimization by coupling random forest with genetic algorithm.

In this work, an electrochemical system was constructed for the simultaneous elimination of ammonia and nitrate using the prepared Ti foam/SnO2-Sb anode and a Cu foam cathode. The hybrid RF-GA method is proposed as a tool for the analysis and optimization of the simultaneous removal of ammonia and nitrate. The influence of independent variables including NaCl concentration, time, and current densities was studied. Results showed that the random forest (RF) model could successfully predict the behavior of electrochemical systems (R2 = 0.9751, RMSE = 0.4567 for the ammonia prediction model; R2 = 0.9772, RMSE = 0.0436 for the nitrate prediction model). The variable importance measures (VIM) analysis reveals that time has the maximum influence on the degradation rate of ammonia and nitrate. The RF model is used as an objective function for the genetic algorithm (GA) to determine the optimum conditions in combination with the calculated specific energy consumption. Based on the optimization results, the removal rates of ammonia and nitrate reach 94.4 % and 74.7 %, respectively, with a minimum specific energy consumption of 0.181 kwh·g-1. The electrochemical reaction mechanism of the composite pollutants in the Ti foam/SnO2-Sb and Cu foam electrode system is further elucidated. The results indicate that nitrate is reduced to nitrite, ammonia, or nitrogen gas at the cathode, accompanied by the mutual transformation of Cu(0), Cu(I), and Cu(II) on the Cu electrode. Ammonia is oxidized to nitrogen gas or nitrate at the anode. Ultimately, the nitrogen-containing composite pollutant is decomposed and discharged as nitrogen gas by cyclic redox reactions.

Efficient degradation of tetracycline by a novel nanoconfinement structure Cu2O/Cu@MXene composite.

In order to solve the problem of easy aggregation of copper oxides in environmental remediation, it is an effective method to confine copper oxides to suitable substrates. Herein, we design a novel Cu2O/Cu@MXene composite with a nanoconfinement structure, and it can effectively activate peroxymonosulfate (PMS) to produce .OH for degradation tetracycline (TC). Results indicated that the MXene with extraordinary multilayer structure and surface negativity could fix the Cu2O/Cu nanoparticles in the layer spaces and suppress the agglomeration of nanoparticles. The removal efficiency of TC reached 99.14 % within 30 min, and the pseudo-first-order reaction kinetic constant was 0.1505 min-1, which was 3.2 times that of Cu2O/Cu alone. The outstanding catalytic performance attributed that the MXene based on Cu2O/Cu@MXene could promote the adsorption of TC and electron transmittal between Cu2O/Cu nanoparticles. Furthermore, the degradation efficiency of TC was still over 82 % after five cycles. In addition, based on the degradation intermediates provided by LC-MS, two specific degradation pathways were proposed. This study provides a new reference for suppressing the agglomeration of nanoparticles, and broadens the application of MXene materials in the field of environmental remediation.

Genome-wide identification and expression analysis of anaphase promoting complex/cyclosome (APC/C) in rose.

The anaphase promoting complex/cyclosome (APC/C) is a large multi-subunit complex, regulating plant development and cell cycle. In plants, the APC/C gene family has been identified in Arabidopsis, rice, and maize. The APC/Cs in rose has not yet been reported. In this study, a total of 19 APC/C genes were identified in rose. Furthermore, we also investigated phylogenetic relationships, chromosomal distribution, gene structure, motif analysis, promoter sequence analysis and expression pattern of RhAPC/C genes. Synteny analysis indicated that AtAPC/Cs and RhAPC/Cs show a high degree of conservation. RhAPC/C promoters contains numerous cis-elements involved in plant morphogenesis, hormone response and stress response. Based on the transcription of RhAPC/Cs in different tissues and developmental stages, it appears that RhAPC/Cs may play a variety of roles in rose growth and development. RhAPC/Cs have limitations in the time and space during which they respond to hormones and abiotic stress. RhAPC5, RhAPC11d, RhAPC13a and RhAPC13c may play a role in rose responding to abiotic stress. The expression of RhAPC10 was altered by infection with fungal pathogen. Our study will serve as a basis for determining the functional role of APC/C genes in roses and help future research on woody plants.

Selenization governs the intrinsic activity of copper-cobalt complexes for enhanced non-radical Fenton-like oxidation toward organic contaminants.

Non-radical oxidation pathways in the Fenton-like process have a superior catalytic activity for the selective degradation of organic contaminants under complicated water matrices. Whereas the synthesis of high-performance catalysts and research on reaction mechanisms are unsatisfactory. Herein, it was the first report on copper-cobalt selenide (CuCoSe) that was well-prepared to activate hydrogen peroxide (H2O2) for non-radical species generation. The optimized CuCoSe+H2O2 system achieved excellent removal of chlortetracycline (CTC) in 10 min at neutral pH along with pleasing reusability and stability. Moreover, it exhibited great anti-interference capacity to inorganic anions and natural organic matters even in actual applications. Multi-surveys verified that singlet oxygen (1O2) was the dominant active species in this reaction and electron transfer on the surface-bound of CuCoSe and H2O2 likewise played an important role in direct CTC oxidation. Where the synergetic metals of Cu and Co accounted for the active sites, and the introduced Se atoms accelerated the circulation efficiency of Co3+/Co2+, Cu2+/Cu+ and Cu2+/Co2+. Simultaneously, the produced Se/O vacancies further facilitated electron mediation to enhance non-radical behaviors. With the aid of intermediate identification and theoretical calculation, the degradation pathways of CTC were proposed. And the predicted ecotoxicity indicated a decrease in underlying environmental risk.

Enhanced peroxymonosulfate activation by hierarchical porous Fe3O4/Co3S4 nanosheets for efficient elimination of rhodamine B: Mechanisms, degradation pathways and toxicological analysis.

Fenton-like catalysts have usually superior catalytic activities, however, some drawbacks of ion leaching and difficult-to-recovery limit their applications. In this work, a hierarchical porous Fe3O4/Co3S4 catalyst was fabricated via a simple phase change reaction to overcome these shortcomings. The introduced iron cooperates with cobalt achieving high-efficiency activation of peroxymonosulfate (PMS) to eliminate Rhodamine B (RhB). The results showed that 0.05 g/L Fe3O4/Co3S4 and 1 mM PMS could quickly remove 100% of 200 mg/L RhB within 20 min, and the removal rate of RhB remained above 82% after 5 cycles. Moreover, the as-prepared Fe3O4/Co3S4 possessed a great magnetic separation capacity and good stability of low metal leaching dose. Radical quenching experiments and electron paramagnetic resonance (EPR) techniques proved that sulfate radicals (SO4•-) were the dominant reactive oxygen species responding for RhB degradation. X-ray photoelectron spectroscopy (XPS) pointed out that the synergism of sulfur promoted the cycling of Co3+/Co2+ and Fe3+/Fe2+, boosting the electron transfer between Fe3O4/Co3S4 and PMS. Moreover, the degradation pathways of RhB were deduced by combining liquid chromatography-mass spectrometry (LC-MS) analysis and density functional theory (DFT) calculations. The toxicities of RhB and its intermediates were evaluated as well, which provided significant assistance in the exploration of their ecological risks.

Enhanced Fenton-like degradation of sulfadiazine by single atom iron materials fixed on nitrogen-doped porous carbon.

The use of single-atom iron catalysts in heterogeneous Fenton-like reactions has demonstrated tremendous potential for antibiotic wastewater treatment. In this study, single-atom iron fixed on nitrogen-doped porous carbon materials (Fe-ISAs@CN) was synthesised using a metal organic framework (MOF) as a precursor. Fe-ISAs@CN was applied as a heterogeneous Fenton catalyst to activate H2O2 for the degradation of sulfadiazine (SDZ) in an aqueous solution. The physical and chemical properties of Fe-ISAs@CN were characterised by scanning electron microscopy (SEM), transmission electron microscope (TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and rotating disk electrode (RDE) measurements. The results of our degradation experiments indicated that Fe-ISAs@CN exhibited remarkable activity and stability for the degradation of SDZ over a wide pH range; even after five cycles, Fe-ISAs@CN retained a high catalytic efficiency (>80%). The 5,5-dimethyl-1-oxaporphyrin-n-oxide (DMPO)-X signal captured by electron paramagnetic resonance (EPR) spectroscopy indicated that a large amount of hydroxyl radicals (OH) was produced in the reaction system. Quench tests indicated that the OH was the main active substance in the degradation of SDZ. The degradation products of the reaction were analysed by High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS), and possible degradation pathways for the SDZ degradation were proposed.

Nano-hybrids of needle-like MnO2 on graphene oxide coupled with peroxymonosulfate for enhanced degradation of norfloxacin: A comparative study and probable degradation pathway.

In this work, 1D MnO2 nano-needles were prepared and grown on the graphene oxide (GO) nano-sheets successfully. The morphology and structure of materials were explored. The MnO2 nano-needles with a length of 200-400 nm were distributed uniformly on the GO nano-sheets. As a result of GO substrate, the MnO2/GO nano-hybrids (MnO2/GO) have the much larger surface area and more surface oxygen-containing functional groups than MnO2 nano-needles, which are beneficial for enrichment and degradation of the norfloxacin (NOR). Results showed that more than 80% NOR was degraded within 20 min at the dose of 10 mM PMS and 0.8 g/L catalysts. Moreover, the optimal pH in MnO2/PMS and MnO2/GO/PMS system were both acidic condition. Furthermore, the mechanism of PMS activation by MnO2/GO was investigated through radical identification using quenching experiments and EPR techniques. According to this, the HSO5- of PMS reacted with Mn (IV)/Mn(III) to form a redox loop, and GO played an important role in the degradation process. Finally, the transformation intermediates of NOR were identified and four probable degradation pathways were speculated. This work would provide a potential contribution towards NOR removal in the environmental remediation.

A nanoscale "yarn ball"-like heteropoly blue catalyst for extremely efficient elimination of antibiotics and dyes.

Fenton system is one of the most popular methods to eliminate antibiotics and dyes in aquatic environment. However, the existed Fenton system is limited by various factors such as potential second pollution and narrow pH range. In this study, we report that the bottlenecks for high strength antibiotics and dyes wastewater treatment at a wide pH range can be well tackled by the nanoscale "yarn ball"-like Mo/W-containing heteropoly blue (HPB) catalyst Mg2Ti6Mo23O119SiW12 (1). This novel catalyst displayed extremely efficient elimination for several typical organic contaminants such as malachite green (MG), tetracycline (TC) and methyl orange (MO). Compared with other materials reported in previous papers, the catalytic performance of 1 in degradation of the organic contaminants of high concentrations increased several times. More than 90% of antibiotics and dyes are degraded within 60 min. Electron spin resonance (ESR) experiments and UV-vis spectra confirmed that the catalytic mechanisms of 1 could mainly ascribe to the 1/H2O2 process and the possible photocatalytic oxidation of adsorbed H2O by holes (h+) in the valence band (VB) of 1 surface generated ·OH for extremely efficient degradation of organic contaminants. This work widens the optimal pH values up to neutral condition and it's significant for the expansion of the heterogeneous Fenton-like catalyst family and its application in the field of water treatment.

A novel biomimetic dandelion structure-inspired carbon nanotube coating with sulfur as a lithium-sulfur battery cathode.

Lithium-sulfur (Li-S) batteries have attracted considerable attention because of their high theoretical energy density. However, poor conductivity and a large volume change in S during cycling, together with a shuttle effect of polysulfides, severely restrict the battery performance, and remain a great challenge. Herein, inspired by a natural dandelion structure, we present a novel biomimetic S-coated carbon nanotube composite consisting of dandelion-like three-dimensional carbon nanotubes coated with S particles on the surface. Carbon nanotubes provide high-speed electron transfer pathways for S during cycling, while the special dandelion-like morphology provides a suitable environment for accommodating the volume change in S upon charge-discharge. The dandelion-like S-coated carbon nanotube-based Li-S batteries exhibit a stable capacity exceeding 760 mAh g-1 after 500 cycles at 0.1 C, along with a Coulombic efficiency as high as 99.9%. Even under repeated rounds of rate-performance measurements, and cycling at different charge versus discharge rates, the batteries retain high capacities and good recovery capabilities. In addition, the proportion of capacitive contribution in the overall capacity is high, indicating a good reversible capacity provided by the composite.

Morphology-tunable WMoO nanowire catalysts for the extremely efficient elimination of tetracycline: kinetics, mechanisms and intermediates.

The presence of antibiotics in aquatic environments has attracted global concern. The Fenton system is one of the most popular methods for eliminating antibiotics in aquatic environments, but the existing Fenton system is limited due to the potential for secondary pollution, and the narrow pH range (∼3-5). In this study, we report that the bottlenecks for high-strength tetracycline (TC) wastewater treatment under neutral conditions can be tackled well by a class of mixed-valence W/Mo containing oxides (WMoO-x) with tunable morphologies. Triethanolamine was selected as a structure-directing agent to control the morphologies of the catalysts going from ultrathin nanowires (UTNWs) to wire-tangled nanoballs (WTNBs). As a proof of concept, the most efficient catalyst in the batch samples, WMoO-1 ultrathin nanowires, was employed as a model material for TC degradation, in which the coordinatively unsaturated metal atoms with oxygen defects serve as the sites for TC chemisorption and electron transfer. As a result, 91.75% of TC was degraded in 60 min for the initial TC concentration of 400 µM. Furthermore, LC-MS analysis confirmed that the TC could be degraded to nontoxic by-products without benzene rings, and finally mineralized to CO2 and H2O. ICP-MS and cycle experiments showed the good stability and reusability of WMoO-1 UTNWs in the Fenton-like system. The findings of this work provide fresh insights into the design of nanoscale catalyst morphology and reaffirm the versatility of doping in tuning catalyst activity, extending the range of the optimal pH values to neutral conditions. This is significant for the expansion of the heterogeneous Fenton-like family and its application in the field of water treatment.

EDTA-Fe(III) Fenton-like oxidation for the degradation of malachite green.

Industrial waste, urban sewage and aquaculture have led to severely increased grades of environment pollutants such as dyes, pesticides and fertilizer. The use of technologies for purifying contaminated waters can be difficult and toxic due to the anti-photolysis, anti-oxidation and anti-bio-oxidation characteristics of organic pollutants, and there is therefore a significant need for new approaches. Here, we report methods of Fenton oxidation and EDTA-Fe(III) Fenton-like oxidation which can be used to degrade malachite green (MG: a dye and antibiotic-like substance) from contaminated water. Compared with the degradation rate (59.34%) of the Fe(III)/H2O2 Fenton process, the EDTA-Fe(III) Fenton-like oxidation got a better degradation rate (92.7%) at neutral pH conditions. By conducting a series of parallel controlled experiments (changing parameters such as the reactant concentration, temperature, and pH), we report the relationships between the degradation effect and different parameters, and we fitted their pseudo first order kinetic curves. Furthermore, we repeated to adjustment of the concentrations of MG in solutions to test the cycle performance and catalytic activities of EDTA-Fe(III)/H2O2 system and it showed good repeatability in the first five rounds and all of them keep the degradation efficiencies greater than 80%. By conducting comparative spin-trapping electron paramagnetic resonance (EPR) experiments, we showed indirectly that the OH contributes to the degradation of MG. Additionally, the results of the EPR experiments showed that EDTA contributes to the generation of OH in the EDTA-Fe(III)/H2O2 Fenton-like system. By conducting total organic carbon (TOC) analysis experiments, we found that EDTA was also oxidized to some extent during the degradation of MG. In all, the findings of this work widen the range of the optimal pH values up to neutral condition for degradation of MG by use of EDTA-Fe(III) Fenton-like system. And this system could be used as one approach for the degradation of organic pollutants at neutral conditions and provide some initial information regarding EDTA-Fe(III) Fenton-like oxidations. It's significant for the expansion of the homogenous Fenton-like family and its application in the field of water treatment.

Super rapid removal of copper, cadmium and lead ions from water by NTA-silica gel.

Copper (Cu2+), cadmium (Cd2+) and lead ions (Pb2+) are toxic to human beings and other organisms. In this study, a silica gel material modified with nitrilotriacetic acid (NTA-silica gel) was sensibly designed and prepared via a simple amidation procedure for the removal of Cu2+, Cd2+ and Pb2+ from water. The NTA-silica gels showed rapid removal performances for the three metal ions (Pb2+ (<2 min), Cu2+ and Cd2+ (<20 min)) with relatively high adsorption capacities (63.5, 53.14 and 76.22 mg g-1 for Cu2+, Cd2+ and Pb2+, respectively). At the same concentration of 20 mg L-1, the removal efficiencies of the three metals by the adsorbent ranged from 96% to 99%. The Freundlich and Langmuir models were utilized to fit the adsorption isotherms. The adsorption kinetics for the three metal ions was pseudo-second-order kinetics. The removal performance of the NTA-silica gels increased in a wide pH range (2-9) and maintained in the presence of competitive metal ions (Na+, Mg2+, Ca2+ and Al3+) with different concentrations. In addition, the NTA-silica gels were easily regenerated (washed with 1% HNO3) and reused for 5 cycles with high adsorption capacity. This study indicates that the NTA-silica gel is a reusable adsorbent for the rapid, convenient, and efficient removal of Cu2+, Cd2+, and Pb2+ from contaminated aquatic environments.

Removal of cadmium and lead ions from water by sulfonated magnetic nanoparticle adsorbents.

A new adsorbent, Fe3O4 sulfonated magnetic nanoparticle (Fe3O4-SO3H MNP), was developed for heavy metal ions removal from water, which could be effectively separated from the solution owing to the superparamagnetic property. The nanoparticles can be used to remove heavy metal ions due to the additional active site, "sulfo-group", introduced by the AMPS branches grafted onto the iron oxide. The as-synthesized materials were characterized by SEM, TEM, FT-IR and BET. The FTIR, XPS and Zeta potential were used to describe the adsorption mechanism. The Fe3O4-SO3H MNPs showed rapid removal for Pb2+ and Cd2+ with maximum of adsorption capacity of 108. 93 and 80.9mg/g at 25°C, respectively. The adsorption isotherms for Pb2+ and Cd2+ fitted better with Langmuir than Freundlich models, indicated that the processes of the removal of Pb2+ and Cd2+ could follow a kind of similar adsorption manner. The adsorption kinetic was consistent with pseudo-second-order model. Furthermore, the reuse experiments results showed the adsorbent might have potential in treating heavy metal ions pollution in water.

Study on the removal of organic micropollutants from aqueous and ethanol solutions by HAP membranes with tunable hydrophilicity and hydrophobicity.

A biocompatible and uniquely defined hydroxyapatite (HAP) adsorption membrane with a sandwich structure was developed for the removal of organic micropollutants for the first time. Both the adsorption and membrane technique were used for the removal of organic micropollutants. The hydrophilicity and hydrophobicity of the HAP adsorbent and membrane were tunable by controlling the surface structure of HAP. The adsorption of organic micropollutants on the HAP adsorbent was studied in batch experiments. The adsorption process was fit with the Freundlich model, while the adsorption kinetics followed the pseudo-second-order model. The HAP membrane could remove organic micropollutants effectively by dynamic adsorption in both aqueous and ethanol solutions. The removal efficiencies of organic micropollutants depended on the solution composition, membrane thickness and hydrophilicity, flow rate, and the initial concentration of organic micropollutants. The adsorption capacities of the HAP membrane with a sandwich structure (membrane thickness was 0.3 mm) were 6700, 6510, 6310, 5960, 5490, 5230, 4980 and 4360 L m-2 for 1-naphthyl amine, 2-naphthol, bisphenol S, propranolol hydrochloride, metolachlor, ethinyl oestradiol, 2,4-dichlorophenol and bisphenol A, respectively, when the initial concentration was 3.0 mg L-1. The biocompatible HAP adsorption membrane can be easily regenerated by methanol and was thus demonstrated to be a novel concept for the removal of organic micropollutants from both aqueous and organic solutions.

A biocompatible and novelly-defined Al-HAP adsorption membrane for highly effective removal of fluoride from drinking water.

A biocompatible and novelly-defined adsorption membrane for rapid removal of fluoride was prepared. Both adsorption and membrane techniques were used in this research. Al(OH)3 nanoparticles modified hydroxyapatite (Al-HAP) nanowires were developed and made into Al-HAP membrane. The adsorption data of Al-HAP adsorbent could be well described by Freundlich isotherm model while the adsorption kinetic followed pseudo-second-order model. The maximum of adsorption capacity was 93.84mg/g when the fluoride concentration was 200mg/L. The adsorption mechanism was anion exchanges and electrostatic interactions. The contribution rates of HAP nanowires and Al(OH)3 nanoparticles in fluoride removal were 36.70% and 63.30%, respectively. The fixed-bed column test demonstrate that the Al-HAP was biocompatible and in a good stability during the process of water treatment. The fluoride removal abilities of Al-HAP membrane with 0.3mm thickness could reach 1568L/m2 when fluoride concentrations were 5mg/L. This study indicated that the Al-HAP membrane could be developed into a very viable technology for highly effective removal of fluoride from drinking water.

A 2D-g-C3N4 nanosheet as an eco-friendly adsorbent for various environmental pollutants in water.

A novel graphitic carbon nitride (g-C3N4) nanosheet adsorbent with a large surface area, remarkable hydrophilicity and high adsorption capacity, was presented for the removal of cadmium ions (Cd2+) and methylene blue (MB) from aqueous solution. Adsorption measurements were conducted systematically to study the influences of the contact time, initial concentrations of Cd2+ and MB, temperature, and pH value. The maximum adsorption capacities of g-C3N4 towards Cd2+ and MB were 94.4 and 42.1 mg g-1, respectively, at 318.5 K when the initial concentrations of Cd2+ and MB were 200 and 20 mg L-1, respectively. The adsorption kinetics fit a pseudo-second-order model. The high adsorption performance of the g-C3N4 adsorbent can be attributed to the multiple adsorption sites on g-C3N4, including the π-π conjugate interactions and electrostatic attractions with pollutants in water. In addition, it is significant to achieve high adsorption performance of g-C3N4 nanosheets by efficiently exposing the adsorption sites by adjusting the microstructure surface properties and dispersity in solution.