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Sulfamethoxazole (SMX) and trimethoprim (TMP) in compound sulfamethoxazole tablets (CSTs) are a typical class of pharmaceuticals, and they belong to the pseudo-POPs due to their persistence and environmental hazard. For the first time, this study investigated the persulfate-assisted mechanochemical destruction of the actual drug, the expired CSTs, to discuss the degradation effect and the degradation mechanism of SMX and TMP. The primary results indicated that NaOH is not suitable to activate persulfate for the treatment of tablets containing starch and that Fe0 performs better than CaO to assist persulfate in the mineralization of organic chemicals. Furthermore, the efficacy of Fe0-activated persulfate-assisted mechanochemical (Fe-PS-MC) degradation of SMX and TMP in the CSTs was investigated. Under the optimum reaction conditions with mass ratios of PS:Fe:SMX = 10:10:1 and PS:Fe:TMP = 10:10:0.2, the degradation was completed within 0.5 h, while the mineralization was completed within 2 h. The ESR spectroscopy confirmed the generation of ˙OH and SO4−˙, providing solid evidence that the MC treatment with PS activated by Fe0 as an additive reagent can efficiently degrade SMX and TMP in the expired CSTs. Finally, the mechanisms of SMX and TMP degradation by the Fe-PS-MC treatment system were set forth, and initiation pathways were proposed.

Ferroelectric perovskites have attracted extensive attention recently, because of their fascinating physical properties and novel characteristics owing to the coupling of electric polarization with other functional properties. Herein, single crystals of a bismuth layered-perovskite ferroelectric oxide Bi2WO6 (BWO) were grown by a flux growth method. The grown crystals exhibit platelet morphology with a dominant (001) orientation face. The linear and nonlinear optical properties of BWO crystals were studied in detail. The optical transmittance spectrum shows that BWO is a direct transition semiconductor with a band gap of 2.75 eV and a wide transmission window up to 5 μm. Second harmonic generation (SHG) measurements indicate that the crystal is also a phase matchable nonlinear optical material with a large SHG response of approximately 2.1 times that of KH2PO4. The dielectric and ferroelectric properties measured perpendicular to the ab plane exhibit an oxygen vacancy associated dielectric loss peak and a non-ferroelectric P–E loop. Moreover, we found that the BWO crystal possesses a significant photoresponse in the broadband wavelength of visible light, showing fast response ( 103), excellent flexibility and robustness. The origin of physical properties was interpreted on the basis of the crystal structure combined with density functional theory (DFT) calculations. The BWO single crystals with large SHG response, rich electrical behavior and broad spectral photoresponse are promising materials for nonlinear optical, electrical and optoelectronic applications.

In this study, water treatment residuals (WTRs), a safe and valuable by-product containing iron, was used as a precursor for preparing effective activator (HWTRs) of peroxymonosulfate (PMS) for imidacloprid (IMD) degradation by hydrothermal treatment. Several affecting parameters on IMD degradation including PMS concentration, HWTRs dosage, initial pH and water matrix were discussed. The results of degradation experiments demonstrated that within the reaction time of 4 h, 97.64% of IMD could be removed with 0.5 g L−1 HWTRs and 1.5 mM PMS, and the acidic conditions were favorable for IMD degradation. Both sulfate radicals (SO4•−) and hydroxyl radicals (·OH) were generated to attack the target pollutant IMD, and ·OH was the dominating radical in the HWTRs/PMS system, which was confirmed by the results of radicals scavenging experiments, electron spin-resonance spectroscopy (ESR) tests and quantitative analysis. What’s more, X-ray photoelectron (XPS) spectroscopy was used to further verify the activation mechanism. Consequently, the activation by Fe(II) on the surface of HWTRs might dominate the reaction was confirmed. In addition, the possible degradation pathways of IMD were proposed on the basis of the degradation intermediates identified by LC-MS. This study offers an innovative idea for modifying raw WTRs to prepare efficient catalysts to activate PMS under relatively mild conditions.

The transformation and transport of Sb are significantly influenced by strong oxides (e.g. MnO2) in the natural environment. Furthermore, Fe(II) can coexist with Sb(III) and MnO2 in waters contaminated by acidic mine drainage. However, role of Fe(II) in Sb(III) oxidation and adsorption by MnO2 remains unclear. Therefore, in the present study, the effects of Fe(II) on the oxidation and adsorption of Sb(III) by MnO2 under acidic conditions (pH 3) and the mechanism thereof were comprehensively investigated. The results of kinetic experiments showed that, in the presence of soluble Fe(II), Sb(III) oxidation is inhibited, but adsorption is promoted. Further characterization confirmed that Fe(III) compounds are formed around MnO2 particles and that these inhibit Sb(III) oxidation. However, two different Fe(III) compounds are formed around MnO2 particles depending on how the Fe(II) is introduced into the experimental system. In the simultaneous oxidation system, poorly crystallized or amorphous Fe Sb precipitates are formed (probably FeSbO4) around MnO2 particles, while in the Fe(II) pretreated oxidation system, schwertmannite is formed. Thus, the present study revealed that Fe(II) is critical to Sb(III) oxidation and adsorption by MnO2 and that the mechanism of its action is depend upon how it is introduced into the reaction system. This information is of relevance to predicting the fate of Sb.

The spatial distribution of phthalate acid esters (PAEs) in sediments of the Jiaozhou Bay and its relationships with anthropogenic activities and environmental variables were investigated in this work. Thirteen PAEs were prevalent in sediments and the total PAE concentrations ranged from 462.1 to 15,133.2 μg/kg. The PAE concentrations increased northeastward and northwestward from the bay mouth in saddle shapes and the highest concentrations were located in the northeastern region according to the spatial distribution patterns generated by geographic information systems. The rivers were the main routes for transporting pollutants into the bay and terrigenous PAEs diluted offshore, so the PAE distribution in sediments was originated from anthropogenic activity intensity. There were strong positive correlations among PAEs with each other, except for di-n-octyl phthalate, and the average residence time (ART) exerted a significant positive impact on the PAE concentrations by Pearson correlation and redundancy analysis. The dibutyl phthalate and di-(2-ethylhexyl) phthalate had high risks to organisms in the northeast and west regions according to the environmental risk limits and risk quotients. The results might provide new insights into the PAE researches and supply information for environmental management and remediation.

Although elevated levels of antimony (Sb) in agricultural soil and plant systems can have harmful effects on human health and ecosystems, little is known about the toxicity of Sb to plants and its mechanism. The assessment of Sb bioavailability is essential for understanding its potential risks and toxicity. In this study, we used pot experiments with two agricultural soil types spiked with Sb to investigate the dose-effect relationship between exposure to Sb and toxic effects (growth and bioaccumulation) on edible amaranth (Amaranthus tricolor Linn.). Soil solution (pore water) and seven single extractants were used to assess the bioavailability of Sb. Different toxic effects of Sb to amaranth cultivated in two types of soils (alkaline and acid soil) were observed. In alkaline soil (chestnut soil, pH 8.39), antimony is more easily absorbed by root and transported to shoot by plants, leading to more adverse effects, than in acid soil (pH 4.91) under the same exposure level. Our findings also highlight the need for more attention on asymptomatic accumulation of Sb in plants, especially for agricultural products cultivated in contaminated areas. The extraction efficiency of Sb was various in different extractants and soil types, Mehlich 3, NaHCO3 and Na2HPO4 for Sb were more efficient than other extractants in both tested alkaline and acid soil. Based on the extractability and correlation coefficients of toxic effects on amaranth and extractable Sb, we found that 0.1 M Na2HPO4 is the best extractant to predict the bioavailability of Sb in soil, and M3 is a suitable alternative. Antimony concentration in soil solution can also be used as an alternative indicator of the bioavailability of Sb.

Many theoretical studies on the photooxidation characteristics of Sb(III) have been performed in recent years, but these characteristics haven’t been well used by now. This research, based on the photooxidation characteristics of Sb(III) and the electrochemical activity difference between Sb(III) and Sb(V), realized the determination of Sb species in a single electrolyte solution by square-wave anodic stripping voltammetry (SW-ASV) without adding any external oxidant or using complex calculations. The electrolyte solution used in this research was 2.0 mol/L HCl, which could promote both the photooxidation of Sb(III) and the electroreduction of Sb(V) by forming chlorination complexes with Sb. Under this condition, Sb(III) had an obvious anodic stripping peak at an enrichment potential of −0.4 V, while Sb(V) was not detected at this enrichment potential. The whole system was exposed to ultraviolet light for a suitable time to ensure that all Sb(III) was oxidized to Sb(V) after the determination of Sb(III). Then, Sb(V) was detected at an enrichment potential of −0.9 V, which represented the total Sb concentration (Sb(tot)) in solution. The original Sb(V) concentration was calculated from the difference between the concentrations of Sb(tot) and Sb(III). Sb(III) photooxidation mechanism investigation proved that O2 play an important role in the photooxidation process and photoinduced H2O2 was the major oxidant of Sb(III). The linear ranges of Sb(III) and Sb(V) were 0.6–1.5 and 0.7–10.0 μmol/L, with detection limits of 4.21 and 5.05 nmol/L, respectively. This method has been successfully applied to Sb speciation and concentration determination in water samples.

Environmental contextThe release of antimony and its compounds to the environment can present a toxic hazard for humans. We evaluated the use of birnessite to dissolve antimony trioxide and found that birnessite accelerated the dissolution process, and ~50% of the oxidised antimony was absorbed. The results can help evaluate the bioavailability of antimony in the environment. AbstractThe most important naturally occurring forms of antimony (Sb) are the ore mineral stibnite (Sb2S3) and its principal weathering product antimony trioxide (Sb2O3). Moreover, most Sb is released into the environment as Sb2O3 from manufacturing, formulations, processing, and the use and disposal of Sb products. In this study, birnessite (δ-MnO2) was employed to promote Sb2O3 dissolution. The Sb2O3 dissolution rate accelerated from ~2% to >99% after 9 days of reaction, and more than 98% of the dissolved SbIII was oxidised into SbV in the presence of birnessite. The birnessite-promoted oxidative dissolution mechanism of Sb2O3 was studied through experiments on the effects of the reaction time and pH. The release rate of Sb in the aqueous phase at the initial stage (335.4 μmol L−1 day−1, pH 6.5) was much higher than that at the late stage (13.28 μmol L−1 day−1, pH 6.5), and when the pH increased from 4.7 to 8.0, the Sb release rate decreased from 351.2 μmol L−1 day−1 to 257.7 μmol L−1 day−1. The dissolution promotion effects of birnessite on Sb2O3 were the most evident under acidic and neutral conditions (the percentages of dissolved Sb2O3 under acidic and neutral conditions were 98.3% and 100.0% after 9 days of reaction). Not all of the produced SbV was released in the reaction solution because ~50% of it was adsorbed by birnessite, and the amount of Sb adsorbed increased with increasing pH. Therefore, alkaline conditions are shown to reduce the release of SbV by inhibiting Sb2O3 dissolution (86.7%) and enhancing SbV adsorption. These results could help clarify the geochemical cycle and fate of Sb in the environment.

With existing and emerging technologies urgently demanding the expansion of the laser wavelengths, high-performance nonlinear optical (NLO) crystals are becoming indispensable. Here, a prospective NLO crystal, Li

In this study, peroxydisulfate (PDS) was successfully activated by nanoscale zero-valent iron (nZVI) for the degradation of sulfamethoxazole (SMX, antibiotic frequently detected in the environment) in agricultural soils. The results indicated that the degradation of SMX was affected by the nZVI dose, the ratio of SMX/PDS, the ratio of soil/water and reaction temperature, and in cinnamon soils 87.6% of SMX degradation can be achieved within 4 h at 30 °C when the initial nZVI dose was 0.03 g g−1 soil, the molar ratio of SMX/PDS = 1/75 and the soil/water = 1/1. The results of radical scavenger experiments and electron spin resonance (ESR) tests showed that hydroxyl radical ( OH) was the dominant reactive species in this system. The ecotoxicity tests of the soil by germination test, luminescent bacteria experiment and enzyme activity test indicated that the ecotoxicity of soil after treatment was obviously lower than the contaminated soil. In addition, there was almost no effect on plant growth when compared with original soil. Furthermore, this system exhibited a great degradation capacity for SMX in different types of agricultural soils, and the degradation efficiencies of SMX in other four soils were 90.6% (yellow brown earths), 80.8% (brown earths), 86.5% (black soils) and 96.1% (red earths), respectively. This work provides an optional method for agricultural soil pollution control.

The anomolous photovoltaic (APV) effect is an intriguing phenomenon and rarely observed in bulk materials that structurally have an inversion symmetry. Here, the discovery of such an APV effect in a centrosymmetric vanadate, BiVO

Lake Qinghai in the Qinghai-Tibet plateau is the largest lake in China. This study firstly reported the geochemistry of Cd in the lake. Water samples were collected from Lake Qinghai (n = 69) and Buha River (n = 12), while sediment (n = 22) and topsoil (n = 45) samples were collected from the lake and around the lake area, respectively. In addition, pore water samples (n = 20) were separated from sediment samples. Water samples were analyzed for pH, K, Na, Ca, Mg, Cl, S, and Cd, while sediment and topsoil samples were analyzed for K, Na, Ca, Mg, Al, Fe, Mn, S, Sc, and Cd. The average concentration of Cd was 0.014 μg L−1 in the water of Lake Qinghai and 0.007 μg L−1 in the water of Buha River. However, the average concentration of Cd was 0.320 μg L−1 in the sediment pore water, much higher than that in the lake water and river water. Cadmium concentration in the lake water might be mainly controlled by salinity, while it in the pore water might be mainly controlled by carbonate minerals. Cadmium concentration in the river water might be controlled by alkalinity and pH. The average concentration of Cd in the sediment was 0.284 mg kg−1. The enrichment of Cd in the lake sediment was significantly higher than that in the topsoil around the lake. Anthropogenic atmospheric deposition of Cd did not led to the increase in dissolved Cd level in the lake water, but led to its enrichment in the lake sediment.

Organic-inorganic hybrid perovskites, with the formula ABX

Objective To obtain the recombinant A-domain of high mobility group box 1 (HMGB1-A) protein. Methods Using genetic engineering techniques, we cloned and recombined rat HMGB1-A gene. Using prokaryotic expression technique, we expressed and purified the recombinant rat HMGB1-A protein, which was verified by Western blotting. Results Agarose gel electrophoresis analysis showed that HMGB1-A cassette gene size was about 250 bp; double digestion for identifying the recombinant clone pUC-A showed that the product size was about 3000 bp, 250 bp; PCR for identifying the recombinant clone pGEX-A showed that the product size was about 250 bp. SDS-PAGE revealed that the product size was about 36 000, which was consistent with the expectation. Conclusion The recombinant rat HMGB1-A was successfully expressed and purified.

A chlorinated polyfluorinated ether sulfonate (F-53B, C8ClF16O4SK) has been widely used as a mist suppressant by the chrome plating industry in China for more than 30 years. It was reported to be moderately toxic and as resistant to degradation as perfluorooctane sulfonate (PFOS). Considering the need for safe disposal of wastes containing F-53B, fast and effective methods are urgently required, of which the mechanochemical destruction (MCD) method seems to be a good alternative. In the present study, sodium persulfate (PS) was tested as a novel co-milling reagent in the MCD process for the degradation of F-53B. F-53B, PS and sodium hydroxide (NaOH) were co-ground in a planetary ball mill, and the ground samples were analyzed by liquid chromatography-mass spectrometry (LC-MS), ion chromatography (IC) and a total organic carbon (TOC) analyzer. Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD) and X-ray photoelectron spectrometry (XPS) analyses were conducted as assistant measures. The results revealed that after 8 h of milling with 60 g balls at the best mass ratio (PS : NaOH : F-53B = 4.17 : 1.75 : 0.05), 88% of F-53B was destroyed, the fluoride recovery efficiency was 54%, and the destruction efficiency closely related to the milling time. TOC analysis showed considerable mineralization of F-53B. Overall, MCD was suggested to be a promising method in the degradation of recalcitrant chemicals like F-53B.

Background: China’s soil pollution poses serious health risks. However, data regarding the soil ingestion rate (SIR) of the Chinese population, which is critical to assessing associated health risks, are lacking. Objectives: We estimated soil ingestion of 177 Chinese children from Guangdong, Hubei, and Gansu Provinces. Methods: We conducted this investigation by employing a tracer mass-balance method. We collected a duplicate of all food consumed and all feces and urine excreted on 1 d (n=153) and over 3 consecutive d (n=24), as well as soil samples from play areas and drinking-water samples. We analyzed concentrations of the tracer elements Al, Ba, Ce, Mn, Sc, Ti, V, and Y in these samples using ICP-AES and ICP-MS and estimated the SIR for each subject. Results: The estimated SIR data based on each tracer element were characterized by a skewed distribution, as well as higher inter-tracer and inter-subject variation, with several outliers. After removing the outliers, daily SIR median (range) values in milligrams per day were Al, 27.8 (−42.0 to 257.3); Ba, 36.5 (−230.3 to 412.7); Ce, 35.3 (−21.2 to 225.8); Mn, 146.6 (−1259.4 to 1827.7); Sc, 54.8 (−4.5 to 292.0); Ti, 36.7 (−233.7 to 687.0); V, 92.1 (10.4 to 308.0); and Y, 59.1 (−18.4 to 283.0). Daily SIR median/95th percentile (range) values based on the best tracer method (BTM) were 51.7/216.6 (−9.5 to 297.6) mg/d. Conclusions: Based on the BTM, recommended SIR values for the general population of Chinese children (2.5 to 12 years old) are 52mg/d for the central tendency and 217mg/d for the upper percentile. We did not differentiate between outside soil and indoor dust. Considering the lower concentration of tracer elements in indoor dust than outside soil, actual soil and dust ingestion rates could be higher. https://doi.org/10.1289/EHP930

Drinking water treatment residuals (WTRs) are safe byproducts of water treatment plants containing iron. This work studies the degradation of atrazine (ATZ) by WTR-catalyzed peroxymonosulfate (PMS) in aqueous solutions. Factors that affect the catalytic performance (the PMS concentration, catalyst dose, initial solution pH, reaction temperature and water matrix species) were investigated. The results show that the catalytic degradation efficiency of ATZ increases with the increase in PMS concentration and temperature, whereas a higher content of WTRs results in lower removal efficiency because of the quenching effect and negative effect of high pH. For an initial solution pH of 3 and 5, 94.1% and 87.4% of ATZ degradation can be achieved within 6h, whereas the value is only 26% for pH of 7. The production of sulfate radicals (SO4-) and hydroxyl radicals (OH) was confirmed by classic radical quenching and electron spin resonance (ESR) tests. Based on the GC-MS and LC-MS results, the main degradation pathways of ATZ may contain dealkylation, dechlorination-hydroxylation, and alkyl chain oxidation processes. In addition to the ATZ removal ability, the WTRs/PMS system can simultaneously remove phosphorus. This article provides a new idea for wastewater treatment and usage of WTRs as a resource.

In this study, iodine-doped granular activated carbon (I-GAC) was prepared and subsequently applied to activate periodate (IO4-) to degrade organic contaminants at ambient temperature. The physicochemical properties of GAC and I-GAC were examined using scanning electron microscopy, N2 adsorption/desorption, Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. No significant difference was observed between the two except for the existence of triiodide (I3-) and pentaiodide (I5-) on I-GAC. The catalytic activity of I-GAC towards IO4- was evaluated by the degradation of acid orange 7 (AO7), and superior catalytic performance was achieved compared with GAC. The effects of some influential parameters (preparation conditions, initial solution pH, and coexisting anions) on the catalytic ability were also investigated. Based on radical scavenging experiments, it appeared that IO3 was the predominant reactive species in the I-GAC/IO4- system. The mechanism underlying the enhanced catalytic performance of I-GAC could be explained by the introduction of negatively charged I3- and I5- into I-GAC, which induced positive charge density on the surface of I-GAC. This accelerated the interaction between I-GAC and IO4-, and subsequently mediated the increasing generation of iodyl radicals (IO3). Furthermore, a possible degradation pathway of AO7 was proposed according to the intermediate products identified by gas chromatography-mass spectrometry.

Thermal activation of persulfate was confirmed to be effective in the destruction of organic pollutants. Microwave heating has different inherent mechanism from that of conventional heating, and the application of microwave heating to chemical reactions has attracted great interest. The objective of this study was to evaluate the degradation of sulfamethoxazole (SMX) in a microwave-activated persulfate (MW/PS) system. The results indicated that MW/PS degradation of SMX followed pseudo-first-order kinetics, and compared with conventional heating, microwave heating has a special effect on SMX degradation with higher reaction rate and shorter process time. The process of SMX degradation was accelerated by higher reaction temperature, persulfate dose or pH in the MW/PS system, while higher initial SMX concentration and the presence of phosphates slowed down the degradation rates. High level of chloride showed some inhibition on the SMX degradation, while low chloride level and carbonate enhanced the SMX degradation. 3-Amino-5-methylisoxazole, sulfanilic acid, hydroxyl-SMX and nitroso-SMX derivatives were identified as the major degradation intermediate products by HPLC/MS. The possible reaction pathways including hydroxylation of the benzene ring, oxidation of the amine group at the benzene ring and the S–N cleavage were proposed. The acute toxicity tests with Photobacterium phosphoreum, Vibrio fischeri and Vibrio qinghaiensis indicated that the inhibitory effect of the 10-time diluted unheated SMX mixture solution being 22.6–48.0%, increased to >99.9% after 4 min and decreased to

The spatial arrangement of biochar and the exact underlying interaction mechanisms of biochar and hydrophobic organic compounds both remain largely unknown. The sorption of dibutyl phthalate (DBP) and phenanthrene (PHE) to plant- and manure-derived biochars in both single- and bi-solute systems was investigated. The significant positive relation between surface polarity and ash content suggests that minerals benefit the external distribution of polar groups on particle surfaces. PHE and DBP sorption by the biochars was regulated by their surface polarity. The PHE generally displayed a pronounced enhancement of DBP sorption, likely resulting from the formation of biochar–PHE–DBP complexes, suggesting that DBP and PHE had different sorption sites on the biochars. The enhancement of Cd 2 + (a soft Lewis acid) on DBP sorption implied that π–π interactions should not dominate DBP sorption by biochars. The influence of Cd 2 + on PHE sorption by biochars would depend on the balance between suppressive sorption by Cd 2 + PHE bonding and enhanced sorption by Cd 2 + -complexed functionalities, and the amounts of Cd 2 + adsorbed by biochars determined the relative role of increased sorption by Cd 2 + in the overall PHE sorption.

A novel l -arginine salt nonlinear optical single crystal, l -arginine p-nitrobenzoate monohydrate (LANB) has been grown by slow cooling method from aqueous solution. Its solubility at different temperatures in water was measured. The grown crystal was characterized by the elemental analyses, X-ray single crystal and powder diffractions, Fourier transform infrared and Raman spectra. The structure analysis revealed that LANB belongs to the monoclinic crystallographic system, space group P21, with unit cell parameters: a = 8.566(3), b = 5.817(2), c = 17.131(7) A, β = 101.223(5)°, Z = 2 and V = 837.2(6) A3. The proton and carbon configurations of l -arginine were confirmed through 1H NMR and 13C NMR spectra analyses. The linear and nonlinear optical properties of LANB crystal were studied by the use of transmission spectrum and second harmonic generation (SHG). The thermal properties were investigated by using thermo gravimetric (TG) and differential thermal analysis (DTA).

Bulk single crystals of CdHg(SCN)4(C2H6SO)2 (CMTD) have been grown by the temperature-lowering method. Refractive index measurements reveal that the refractive index nx along the c axis is much smaller than the ny and nz indices in the ab-plane. The detailed powder second-harmonic generation (SHG) measurements using 1064 nm radiation indicate that the crystal is a phase matchable nonlinear optical material which exhibits a strong SHG effect, 1.2 times that of KTiOPO4. The complete set of dielectric, elastic and piezoelectric constants of CMTD have been measured and the results show that the crystal possesses excellent piezoelectric properties of d36 = 20.40 and d14 = 17.80 pC N−1 (much larger than those of α-SiO2). The crystal exhibits a neutral layered structure consisting of the asymmetric HgS4 tetrahedron and CdN4O2 octahedron which are connected by π-conjugated –SCN– ligands. The physical properties have been interpreted on the basis of the crystal structure combined with theoretical calculations. The strong piezoelectric response and high optical SHG efficiency make CMTD a promising candidate for both piezoelectric and nonlinear optical applications.

Bulk single crystals of diguanidinium phosphate monohydrate (G2HP) with dimensions up to 55 × 28 × 27 mm3 have been grown by solution growth methods. Thermal properties including specific heat, thermal conductivity and thermal expansion were investigated as a function of temperature. The specific heat was measured to be 1.339 to 1.614 J g−1 K−1 over the temperature range of 293 to 347 K. The thermal conductivities are descending as the temperature increases. The average linear thermal expansion coefficients along a and c axes from 298 to 338 K are α11 = 1.878 × 10−5 K−1 and α33 = 1.930 × 10−5 K−1, respectively. The laser-induced damage threshold measurements show that the G2HP crystal possesses an excellent resistance to laser radiation with a high threshold up to 5.29 GW cm−2. The optical behaviors, including the transmission spectrum and reflective indexes, were investigated to study its linear and nonlinear optical properties. The results reveal that the crystal is a phase matchable nonlinear optical material in the visible and UV regions. A complete set of dielectric, elastic and piezoelectric constants of G2HP have also been measured, and the results display that the crystal also possesses fine piezoelectric properties with d14 = 10.00. Furthermore, the structure–property relationships are discussed on the basis of the crystal structure combined with theoretical calculations. As a multi-functional crystal, G2HP is a particularly promising candidate for a variety of potential applications in many fields.

Little is known about the variation of Chinese children's exposure to arsenic by geography, age, gender, and other potential factors. The main objective of this study was to investigate the total arsenic concentration in Chinese children's urine by geographic locations, ages, and genders. In total, 259 24-h urine samples were collected from 210 2- to 12-year-old children in China and analyzed for total arsenic and creatinine concentrations. The results showed that the upper limit (upper limit of the 90% confidence interval for the 97.5 fractile) was 27.51 µg/L or 55.88 µg/g creatinine for Chinese children. The total urinary arsenic levels were significantly different for children in Guangdong, Hubei, and Gansu provinces (P 0.05), where the upper limits were 24.29, 58.70, and 44.29 µg/g creatinine, respectively. In addition, the total urinary arsenic levels were higher for 2- to 7-year-old children than for 7- to 12-year-old children (P 0.05; the upper limits were 59.06 and 44.29 µg/g creatinine, respectively) and higher for rural children than for urban children (P 0.05; the upper limits were 59.06 and 50.44 µg/g creatinine, respectively). The total urinary arsenic levels for boys were not significantly different from those for girls (P 0.05), although the level for boys (the upper limit was 59.30 µg/g) was slightly higher than that for girls (the upper limit was 58.64 µg/g creatinine). Because the total urinary arsenic concentrations are significantly different for general populations of children in different locations and age groups, the reference level of total urinary arsenic might be dependent on the geographic site and the child's age.

Concentrations of widely used antibiotics were predicted to be the highest in the Haihe River Catchment across China previously, potentially resulting in high ecotoxicological risks in this region. As a result of growing usage and regulation of antibiotic use in animals, the pattern of use may have altered temporally for different antibiotics. It is important to monitor the occurrence of antibiotics within different categories for understanding their mass loading to the catchment and the potential ecotoxicological risks involved. This study investigated the seasonal occurrence and spatial variation of 15 antibiotics in the Haihe River Catchment during 2016–2017. The investigated compounds included veterinary antibiotics, human-use antibiotics, and those intended for both human and animal use. Measurements reported from previous studies were compared with the results of this study and indicated that the use of veterinary antibiotics is probably increasing around the catchment. The ∑antibiotics concentration (i.e. the summed concentration of the 15 target antibiotics) ranged from 414 to 1951 ng/L, with an average of 821 ng/L. Discharges from wastewater treatment plants were the main sources of these compounds. The mass loading of antibiotics to the river waters was higher during wet seasons than during dry seasons. The mass fluxes of the antibiotics continuously increased towards the lower reaches of the rivers. The total annual input of the antibiotics from the Haihe River and Yongdingxin River into the Bohai Bay was 5008 kg/yr. Ofloxacin, trimethoprim, leucomycin, anhydro erythromycin and florfenicol were the predominant antibiotics, whilst amoxicillin, anhydro erythromycin, ofloxacin, norfloxacin and enrofloxacin may pose high ecotoxicological risks to the investigated aquatic ecosystem. Several antibiotics selected in this study were reported for the first time in this catchment. This study provides important information for chemical management and indicates that further monitoring is needed on the more harmful and veterinary antibiotics in the catchment. Keywords: Haihe River Catchment, Antibiotics, Mass flux, Diffuse pollution, Ecotoxicological risk

2D hybrid perovskites have shown great promise in the photodetection field, due to their intriguing attributes stemming from unique structural architectures. However, the great majority of detectors based on this 2D system possess a relatively low response speed (≈ms), making it extremely urgent to develop new candidates for superfast photodetection. Here, a new organic-inorganic hybrid perovskite, (PA)2 (FA)Pb2 I7 (EFA, where PA is n-pentylaminium and FA is formamidine), which features the 2D Ruddlesden-Popper type perovskite framework that is composed of the corner-sharing PbI6 octahedra is reported. Significantly, photodetectors fabricated on highly oriented thin films, which exhibit a perfect orientation parallel to 2D inorganic perovskite layers, exhibit a superfast response time up to ≈2.54 ns. To the best of the knowledge, this figure-of-merit catches up with that of the top-ranking commercial materials, and sets a new record for 2D hybrid perovskite photodetectors. Moreover, extremely high photodetectivity (≈1.73 × 1014 Jones, under an incident power intensity of ≈46 µW cm-2 ), considerable switching ratios (>103 ), and low dark current (≈10 pA) are also achieved in the detector, indicating its great potential for high-efficiency photodetection. These results shed light on the possibilities to explore new 2D candidates for assembling future high-performance optoelectronic devices.

Two novel heterometallic complexes with Hg(II) and Fe(II) as coordination centres have been synthesised and characterised by means of infrared, single crystal X-ray diffraction and magnetic measurements. The compounds FeHg(SCN)4(C3H7NO)2 (FMTF) and FeHg(SCN)4(N2H4CS)4 (TMTF) form supramolecular framework structures. The FMTF adopts a multidimensional structure, while TMTF creates a one-dimensional chain extending along the crystallographic direction [0 0 1]. Variable temperature magnetic susceptibility measurements show different degrees of deviation from Curie modelled behaviours. In both salts, large zero field splitting mainly contributes to their downturns, while in TMTF, the antiferromagnetic interactions within the chains should also be taken into account.

A novel organic crystal, L-lysine p-nitrophenolate monohydrate (LLNP) has been grown successfully from an aqueous solution by the slow cooling method. Transparent single crystal of dimensions 22 × 12 × 12 mm3 has been obtained. The single crystal X-ray diffraction has shown that LLNP belongs to the orthorhombic crystallographic system with space group P212121. The functional groups and vibrational frequencies of the crystal have been identified using IR and Raman spectra. The proton and carbon configurations have been confirmed through 1H-NMR and 13C-NMR spectra analyses. The UV-Vis-NIR transmittance spectrum for LLNP crystal has been recorded in the range from 200 to 2500 nm. The second harmonic generation (SHG) intensity of LLNP has been measured by powder SHG method and found to be as 4.2 times as that of KDP. The thermal properties have been studied by using thermo gravimetric (TG) and differential thermal analysis (DTA).

Adsorption is an effective method for the removal of heavy metal ions from wastewater. However, technologies are needed to regenerate the saturated adsorbents for reuse and to immobilize the adsorbed heavy metal ions for the final disposal of the disused adsorbents. The presence of humic acid in water may influence adsorption and the subsequent immobilization of heavy metal ions. In this study, microwave irradiation was adopted to regenerate granular activated carbon (GAC) saturated with Cd2+ and to also immobilize Cd2+ onto GAC. The effects of humic acid on adsorption of Cd2+ onto GAC and the immobilization of Cd2+ by microwave irradiation were investigated. The results showed that specific concentrations of humic acid promoted the adsorption of Cd2+ onto GAC as well as the immobilization of Cd2+ by microwave irradiation, which may be attributed to the complexation of humic acid with Cd2+, as indicated by the three-dimensional fluorescence spectra. Several important parameters including microwave power, irradiation time and water content of GAC were found to have significant effects on the immobilization of Cd2+ onto GAC by microwave irradiation. Evaluation based on the toxicity characteristic leaching procedure (TCLP) showed that for the dried GAC, approximately 89% immobilization of Cd2+ was achieved with 750 W of microwave irradiation for 10 min. This technology may also be effective for the immobilization of other metal ions, including Cu2+, Zn2+ and Pb2+.

The quantitative assessment of P contamination in sediments is a challenge due to sediment heterogeneity and the lacking of geochemical background or baseline levels. In this study, a procedure was proposed to determine the average P background level and P geochemical baseline level (GBL) and develop P geochemical baseline functions (GBF) for riverbed sediments of the Liao River Watershed (LRW). The LRW has two river systems - the Liao River System (LRS) and the Daliao River System (DRS). Eighty-eight samples were collected and analyzed for P, Al, Fe, Ca, organic matter, pH, and texture. The results show that Fe can be used as a better particle-size proxy to construct the GBF of P (P (mg/kg) = 39.98 + 166.19 × Fe (%), R(2) = 0.835, n = 66). The GBL of P was 675 mg/kg, while the average background level of P was 355 mg/kg. Noting that many large cities are located in the DRS watershed, most of the contaminated sites were located within the DRS and the riverbed sediments were more contaminated by P in the DRS watershed than in the LRS watershed. The geochemical background and baseline information of P are of great importance in managing P levels within the LRW.

The quantitative assessment of heavy metal contamination in the sediments is a challenge due to the lacking of geochemical background or baseline levels and sediment heterogeneity. In this study, a procedure is suggested to elucidate the average background levels and geochemical baseline levels (GBLs) of Cr, Cu, Ni, Pb, and Zn in the Liao River Water sediments and to develop their geochemical baseline functions (GBFs). The average background levels of Cr, Cu, Ni, Pb, and Zn were 32.6, 11.1, 13.1, 16.3, and 37.8 mg/kg, respectively; while their GBLs (the upper limit of background level) were 60, 21, 27, 23, and 96 mg/kg. The linear correlation of heavy metals (Cr, Cu, Ni, Pb, and Zn) with particle-size proxy elements (normalizers) Sc, Fe, and Al was statistically significant at p

Biochars are increasingly recognized as effective, inexpensive, and environmentally friendly sorbents for abating organic contaminants. In this study, the sorption and competitive sorption characteristics of simazine (SZ), metsulfuron-methyl (ME), and tetracycline (TC) to corn straw biochars and soil were examined to understand the interactions of herbicides and antibiotics with biochars and the potential role of biochars as engineered sorbents. Biochars were obtained by pyrolyzing corn straw at 400, 500, and 600 °C for 6 h under oxygen-limited conditions and were characterized via elemental analysis, N2-BET surface area determination, 13C nuclear magnetic resonance spectroscopy, and Fourier transform infrared spectroscopy. Soil was collected from North Tanggu Farm in Tianjin, and its organic carbon, cation exchange capacity, and particle size distribution were analyzed. The batch sorption experiments were performed to obtain the sorption isotherms of SZ, ME, and TC to biochars and soil. The biochars that were pyrolyzed at higher temperatures had higher sorption affinities for SZ, ME, and TC, which may be due to the enhancement of hydrophobic interactions, charge transfer (π–π*) interactions, and pore-filling mechanism. The sorption affinities for these compounds to all biochars decreased in the order SZ > TC > ME, indicating that the neutral molecule with a stronger hydrophobicity is more easily adsorbed by biochars. For soil, the decrease of the sorption affinities followed the order TC > SZ > ME due to the high sorption affinity of TC with clays in the soil. Moreover, the sorption affinities of TC by biochars were lower than by soil, indicating that corn straw biochars may be not an ideal sorbent for the immobilization of TC. Biochars were much more effective in sorbing SZ and ME than soil, indicating that corn straw biochars can potentially prevent transport of the herbicides to surface and ground water. Nevertheless, the presence of TC significantly hinders biochar adsorption of SZ and ME, implying that the coexisting contaminants should be considered when developing biochars as engineered sorbents. The observations in this study demonstrated that the sorption of organic contaminants by biochars is dependent on the properties of the biochars and the molecular structures of the contaminants. Corn straw biochars effectively retain SZ and ME and hinder their transportation to surface and ground water; however, the coexisting contaminants should be considered. Our results will be helpful for designing biochars as engineered sorbents for environmental applications.

This study investigated the arsenic (As) distribution and adsorption behavior in sediments of the Daliao River System (DRS). Results indicated that the total As was 2.6-83.1 mg kg(-1) in the sediments of the DRS. The pseudo-first order model and intra-particle diffusion model give a good fit of the experimental kinetics data for As, indicating that particle diffusion mechanism may not be the rate controlling step while this mechanism is involved. By comparing the zero equilibrium As concentration (EAsCo) with the actual As concentration in the overlying water of the DRS, all the sediments showed a trend of releasing As. Arsenic exhibited strong adsorption on sediment at pH 4.5-7. Arsenic retention by sediment was much enhanced by Ca2+ compared to Na+. More As was desorbed by phosphate at low and high pH extremes. The added or sorbed As was mainly transferred to the specifically sorbed fraction and amorphous Fe (Al) oxyhydroxides bound fraction, indicating Fe oxides are a major sorbent of As in sediment.

The preparation, crystal structures and physicochemical characterization of two magnetic polymers, ethyl-triphenylphosphate (ETPP) [Ni(dmit)2] (compound 1) and propyl-triphenylphosphate (PTPP) [Ni(dmit)2] (compound 2) (dmit = 2-thioxo-1,3-dithiol-4,5-dithiolate), have been described. The magnetic susceptibilities (χm) have been measured between 10 and 300 K. The χm values of 1 can be well reproduced by the sum of the contributions from a standard Curie system and a dimer with negative exchange interaction of J/k = −320.59 K, which is extremely strong among dmit complexes. The dimer formation in Ni(dmit)2 anions have been ascertained by the crystal structure analysis. In 2, every two Ni(dmit)2 dimer molecules are connected by the short side-by-side distance between sulfur atoms, indicating the formation of a nonlinear tetramer. The magnetic susceptibility data have been fitted to a four-spin model using the g value obtained in EPR spectroscopy, and ended up with a plane-to-plane interaction of J1/k = −200.89 K and a sideways interaction J2/k = −33.69 K.

The quantitative contamination assessment of toxic elements in sediments is a challenge due to the lack of their geochemical background or baseline levels and sediment heterogeneity. Eighty-eight sediment samples were collected in the Liao River Watershed (LRW) and analyzed for Co, Mn, V, Sc, Fe, Al, and sediment properties. The average background levels, geochemical baseline levels (GBL), and geochemical baseline functions of Co, Mn, and V in the sediments were obtained using statistical and geochemical methodologies. The concentrations of Co, Mn, and V were 0.86 to 23.40, 105.9 to 1771.6, and 6.47 to 153.30 mg/kg, respectively. The average background levels and GBLs were 7.2 and 14.4 mg/kg for Co, 422 and 762 mg/kg for Mn, and 35.4 and 59.0 mg/kg for V. The linear correlation of Co, Mn, and V with particle-size proxy elements (normalizers) Sc, Fe, and Al was statistically significant with probability (p-value)

Mesoporous and nanostructured Fe-doped TiO2 fibers were fabricated on a large scale by sol–gel method combined with the polyorganotitanium as the precursor and ferric nitrate as dopant. The prepared fibers were characterized by XRD, XPS, SEM, TEM, N2 adsorption–desorption isotherms and UV–vis spectroscopy. The photocatalytic activity was evaluated by photodegradation of methyl orange (MO) aqueous solution under UV and visible-light irradiation. Compared with different types of photocatalysts, the 0.5%Fe-doped TiO2 fibers exhibit super photocatalytic activity. This is ascribed to the fact that the Fe-doping induces the shift of the absorption edge into the visible-light range with the narrowing of the band gap and reduces the recombination of the photo-generated electrons and holes. Furthermore, first-principle study for their electronic structures was carried out to confirm the effects of different replaced lattice sites on the red shift of the absorption edge and the changes of the band gap of the Fe-doped TiO2 fibers.

The Daliao River System (DRS) is one of the major river systems in the northeastern China and receives substantial discharges from industrial, municipal, and agricultural effluents. In this study, the contents and partition of toxic trace elements in the DRS sediments were evaluated in terms of contamination levels and ecological risks using geoaccumulation index (Igeo), relative enrichment factor (REF), sediment pollution index (SPI), and potential effect concentration quotient (PECQ). Fourteen samples were collected and measured for trace and major elements and sediment properties. The following concentration ranges (mg kg−1) of toxic trace elements were found: As, 1.6–18.0; Cd 0.1–0.9; Co 3.8–23.4; Cr 12.9–151.6; Cu 4.6–86.1; Hg 0.01–0.35; Ni 8.4–64.4; Pb 11.6–67.1; Sb 0.13–1.77; V 18.5–153.3; and Zn 20.4–211.3. The proportions of soluble and exchangeable trace metals were less than 1 %, while the proportions of trace metals bound to carbonate, amorphous oxides, organic matter, and crystalline oxides were usually each

Co x Mg 1− x Al 2 O 4 ( x = 0–0.8) nanoparticles were synthesized by sol–gel method, and characterized by X-ray powder diffraction and transmission electron microscopy. X-ray photoelectron spectroscopy and 27 Al solid-state NMR spectroscopy were performed to study the chemical environments of cations in the nanoparticles as a function of cobalt content and annealing temperature. The results show that the crystallite size of the particles is about 20–40 nm. Besides the tetrahedral and octahedral coordinations, the second octahedrally coordinated Al 3+ ions are observed in the samples. The inversion parameter (two times the fraction of Al 3+ ions in tetrahedral sites) decreases with the increase of annealing temperature and cobalt content. The fraction of octahedral Mg 2+ decreases with the increase of Co concentration. The absorption spectra indicate that Co 2+ ions are located in the tetrahedral sites as well as in the octahedral sites in the nanoparticles. The intensity of the absorption peak corresponding to octahedral Co 2+ ions (300–500 nm) decreases with increasing annealing temperature.

A series of organic nonlinear optical (NLO) materials based on the stilbazolium derivatives of 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium tosylate (DAST) were synthesized, and the single crystals were grown from the solutions. Single-crystal structure determinations and Kurtz powder tests reveal that replacement of the p-toluenesulfonate anion in the DAST crystal, forming 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium 4-aminotoluene-3-sulfonate (1) and 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium p-chlorobenzenesulfonate (2), constructs new acentric crystals with quite a large powder second-harmonic generation (SHG) of more than 3 orders of magnitude larger than that of urea around 2.0 μm, whereas the other two complexes show their centrosymmetric structures without any SHG effects. A possible estimation of the molecular first hyperpolarizabilities βijk performed on 2 further confirms its origin of its enhanced NLO merits. Furthermore, both 1 and 2 exhibit even higher environmental stabilities, includi...

The application of biochars into soil may influence the fate of contaminants. Sorption and competitive sorption of metsulfuron-methyl (ME) and tetracycline (TC) on corn straw biochars prepared at 100 to 600°C (referred to as CS100-CS600) were examined. The Freundlich model described sorption isotherms well. The lower sorption capacity () of ME compared with TC on the biochars was attributed to the electrostatic repulsion between the anionic ME and the negatively charged biochars. No electrostatic repulsion between the zwitterionic TC and the biochars occurred. Tetracycline exhibited little competition with ME for CS100-CS300 in bi-solute systems, suggesting that partitioning of ME into noncarbonized rubbery organic matter might be the dominant sorption mechanism. The nonlinear isotherms of ME on CS400-CS600 and those of TC on CS100-CS600 suggested adsorption as the dominant mechanism. A significant increase in the Freundlich values in the bi-solute systems might be attributed to TC/ME occupying and blocking ME/TC-specific adsorption sites. The percentage decreases in of TC on CS400-CS600 with low ME concentrations were lower than those on CS200-CS300. This might be attributed to the lower steric restriction of ME for TC on CS400-CS600 because of their larger specific surface areas. The larger percentage decrease in of ME with TC from CS400 to CS600 may be explained by a decrease in the hydrophobicity and the increased sorption of TC with numerous polar groups. When using biochars as engineered sorbents to prevent the transport of ME from soil, the effect of coexisting TC needs to be taken into account.

The sorption behaviors of diuron (DIU), fluridone (FLU) and norflurazon (NOR) by a single-walled carbon nanotube (SWCNT) and three multi-walled carbon nanotubes (MWCNT) samples including MWCNT10 (10nm, outer diameter), MWCNT20 (10-20 nm), and MWCNT40 (20-40 nm) were investigated. All adsorption isotherms were nonlinear and were well fitted with the Freundlich model and Dubinin Ashtakhov (DA) model. The linear relationships between the organic carbon (OC)-normalized saturated adsorption capacity (Q(0)(OC)) and surface area (SA) suggest that SA is presumably responsible for the adsorption of DIU and NOR on CNTs. While FLU, DIU, and NOR OC-normalized distribution coefficients (logK(OC)) of CNTs increased with increasing their hydrophobicity (logK(OW)) and the positive relationships between the logK(OW)-normalized logK(OC) (i.e., logK(OC)/logK(OW)) of FLU, DIU, and NOR and their hydrogen bonding ability indicate that the adsorption of FLU, DIU and NOR was mainly controlled by the hydrophobic interaction and hydrogen bonding. The higher logK(OC) or Q(0)(OC) values of MWCNT10 and SWCNT relative to other large MWCNTs and carbonaceous adsorbents suggest that MWCNT10 has the potential to serve as an adsorbent used to reduce the mobility of herbicides in agricultural and environmental applications.

Experimental measurements, including circular dichroism (CD) spectroscopy and optical rotations have been employed to characterize the changing tendency of molecular conformations of the full protonated l -arginine (LA 2+ ) in aqueous solution with the rising of temperature. Calculating methods, including conformational search, molecular structural optimization, CD responses as well as specific rotation calculations have been performed to interpret experimental results. Calculated results, no matter in CD spectra or specific rotations, are consistent with experiments, which strongly certify the transformation of molecular conformations. This successful reproduction of experimental results with molecular simulations in both areas of CD responses and optical rotations is of great significance. More detailed analysis about the relationship between LA 2+ molecular structure and the optical activity has been conducted.

In this study, the bisulfite-peroxydisulfate system (S(IV)/PDS) widely used in polymerization was innovatively applied for organic contaminants degradation in water. The addition of S(IV) into PDS system remarkably enhanced the degradation efficiency of bisphenol A (BPA, a frequently detected endocrine disrupting chemical in the environments) from 17.0% to 84.7% within 360 min. The degradation efficiency of BPA in the S(IV)/PDS system followed pseudo-first-order kinetics, with rate constant values ranging from 0.00005min-1 to 0.02717min-1 depending on the operating parameters, such as the initial S(IV) and PDS dosage, solution pH, reaction temperature, chloride and water type. Furthermore, nitrogen purging experiment, radical scavenging experiment and electron spin resonance (ESR) analysis were used to elucidate the possible mechanism. The results revealed that sulfate radical was the dominant reactive species in the S(IV)/PDS system. Finally, based on the results of liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS), the BPA degradation pathway was proposed to involve β-scission (CC), hydroxylation, dehydration, oxidative skeletal rearrangement, and ring opening. This study helps to characterize the combination of PDS and inorganic S(IV), a common industrial contaminant, to generate reactive species to enhance organic contaminants degradation in water.

Toxic elements have caused great concern due to their adverse health effects. Biological monitoring is generally considered to be a useful tool to assess human exposure to these elements during risk assessment. To better interpret the biological monitoring data, elemental reference values are critical. The major objectives of this study were to clarify whether first-spot morning urine can serve as a surrogate for 24-h urine and to determine the concentration reference interval of some elements in Chinese children's urine. In total, 259 first-spot morning urine samples and 24-h urine samples were collected from 210 2- to 12-year-old healthy children in China and analyzed for creatinine, aluminum, barium, manganese, titanium, cerium, scandium, vanadium, yttrium, and arsenic. The results showed that the creatinine-adjusted concentrations of aluminum, barium, manganese, titanium, cerium, scandium, vanadium, yttrium, and arsenic in the first-spot urine were significantly correlated with those in the 24-h urine. This showed that first-spot morning urine is a favored matrix for monitoring element exposure due to its easy collection and low collection cost. The reference interval using ng/mg creatinine as the unit for Chinese children's urine was 1.63-2653 for aluminum, 3.71-116.8 for barium, 0.67-91.77 for titanium, 0.20-53.42 for arsenic, 1.36-25.29 for manganese, 0.24-8.59 for vanadium, 0.02-2.27 for cerium, 0.01-0.65 for yttrium, and 0.002-0.483 for scandium. These reference intervals may provide reference levels to assess Chinese children's exposure to these elements.