The social and environment effects of illicit drug abuse are a growing global concern. Wastewater-based epidemiology (WBE) has become a common monitoring tool for assessing drug consumption. In this study, mechanical carrier (MGO), skeletal framework (ZIF-67) and functional modification (DES) were together prepared a three-dimensional nanocomposite (DES/ZIF-MGO) as an adsorbent, and developed an ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method coupled with optimal MSPE for the determination of ultra-trace illicit drugs in wastewater. The method exhibited good linearity (R2 >= 0.9985) with low limit of detection (0.02-1.55 mu g/L) and qualified recovery (92.1-100.9 %) for four illicit drugs (AM, METH, MDMA and MC). The characterization results showed that electrostatic, hydrogen bond, and pi-pi interaction contributed to the adsorption process. The drug consumption in a city was investigated using WBE. MC was not detected in any of the wastewater samples. The detection rates of METH and MDMA were 100 % and 82 %, respectively, while AM was found in about 18 % of the wastewater samples. Thus, based on advantages of the DES/ZIF-MGO nanocomposite, the proposed method is a rapid, sensitive and reliable method for the determination of trace illicit drugs in wastewater.

Mephedrone (4-methylmethcathinone, MEPH) exhibited severe ecologic hazards and health detriments. A novel deep eutectic solvent functionalized magnetic ZIF-8/hierarchical porous carbon (DMZH) with excellent selectivity, interference resistance and recyclability, was developed for the rapid adsorption of MEPH. Initially, potential adsorption sites of MEPH were predicted. Then, pi-pi and hydrogen bonding interactions were proposed and verified from characterizations, comparative experiments and theoretical calculations. The synergistic effects of the hydrogen bonding and pi-pi interactions increased the adsorption energies from -15.26 kcal & sdot;mol(-1) to -21.83 kcal & sdot;mol(-1), enhanced the degree of pi-dissociation, enlarged the pi-pi isosurface area, extended the van der Waals surface mutual penetration distance, achieving stronger affinity and remarkable adsorption. Furthermore, offset (parallel-displaced) pi-pi stacking form existed between DMZH and MEPH. DMZH acted as the hydrogen bond donor and MEPH served as the hydrogen bond acceptor to form O-H & ctdot;O and N-H & ctdot;O hydrogen bonding interaction. Profiting from the synergistic effects, DMZH showed satisfactory adsorption for MEPH within 20 min with a maximum adsorption capacity of 3270.11 mu g center dot g(-1), displayed excellent performance in wide pH range of 5 similar to 11 and in the coexistence of multi-chemicals.

A new adsorbent(DES@ZIF@MG) was prepared by grafting deep eutectic solvents(DES) onto metal organic framework ZIF/magnetic reduced graphene oxide(MG) for the adsorption of methamphetamine. A series of structural characterization analyses (SEM, FT-IR, BET, VSM, TGA) were facilitated to explore the microscopic morphology and physicochemical properties of DES@ZIF@MG. The adsorption performances of methamphetamine onto the adsorbent were investigated by adsorption kinetics, isotherms, and adsorption effect experiments(pH, ionic strengths, and humic acid). The results showed that the adsorption of methamphetamine onto DES@ZIF@MG was consistent with the pseudo-second-order model and the Langmuir model, indicating that the adsorption process was an energetically homogeneous adsorption dominated by chemisorption. The XPS characterization illustrated that the adsorption process of methamphetamine by DES@ZIF@MG mainly involved hydrogen bonding, π-π interaction, electrostatic interaction, and chelation.

The efficient and selective removal of amphetamine (AMP) from water bodies is significant for environmental remediation. In this study, a novel strategy for screening deep eutectic solvent (DES) functional monomers was proposed based on density functional theory (DFT) calculations. Using magnetic GO/ZIF-67 (ZMG) as substrates, three DES-functionalized adsorbents (ZMG-BA, ZMG-FA, and ZMG-PA) were successfully synthesized. The isothermal results showed that the DES-functionalized materials introduced more adsorption sites and mainly contributed to the formation of hydrogen bonds. The order of the maximum adsorption capacity (Q(m)) was as follows: ZMG-BA (732.110 mu g.g(-1)) > ZMG-FA (636.518 mu g.g(-1)) > ZMG-PA (564.618 mu g.g(-1)) > ZMG (489.913 mu g.g(-1)). The adsorption rate of AMP on ZMG-BA was the highest (98.1%) at pH 11, which could be explained by the less protonation of -NH2 from AMP being more favorable for forming hydrogen bonds with the -COOH of ZMG-BA. The strongest affinity of the -COOH of ZMG-BA for AMP was reflected in the most hydrogen bonds and the shortest bond length. The hydrogen bonding adsorption mechanism was fully explained by experimental characterization (FT-IR, XPS) and DFT calculations. Frontier Molecular Orbital (FMO) calculations showed that ZMG-BA had the lowest HOMO-LUMO energy gap (E-gap), the highest chemical activity and the best adsorption

Development of a superior water pretreatment for monitoring the psychoactive substances in urban is requisite. Herein, a novel adsorbent with selective adsorption capacity for methamphetamine (MAMP) has been successfully designed through deep eutectic solvents (DES) as a modifier was used to regulate magnetic reduced graphene oxide/ZIF-67 (MGZ) composites. The DES, named as Choline chloride/Levulinic acid (LA), with high affinity towards MAMP, was screened by density functional theory (DFT). The DESs regulated MGZ to synthesize DES/MGZ, and the adsorption performances of diverse DES/MGZ were investigated by contrast experiment. The selective adsorption performances were investigated by selective experiment with multiple compounds. The MAMP adsorption amount of LA/MGZ was 365.96 & mu;g g-1, and enhanced 82.98% than MGZ (200.67 & mu;g g-1). The characteristic of pH-dependent occurred on the MAMP adsorption by LA/MGZ was attributed to the exfoliation of highly oxidized debris promote H-bonding and 7C-7C interactions between LA/MGZ and MAMP. Theoretical calculations in combination with characterization analyses illustrated the efficient recognition of LA toward MAMP was mainly dependent on the H-bonding interactions between carboxyl groups of LA and the -NH of MAMP, as well as the electron transfer from MAMP to levulinic acid. The proposed strategy in this work for designing DESs as a modifier to regulate the carrier materials based on DFT calculations to improve the selective adsorption ability would inspire more ideas in efficient water environmental treatment.

Exploring the structure-dependent adsorption mechanism of contaminants in wastewater is beneficial to high-efficiency adsorbents design and environmental remediation. In this study, emerging porous material of zeolitic imidazolate framework-67 (ZIF-67) has been modified by the magnetic graphene oxide-polydopamine nanohybrid (mGOP) to obtain three-dimensional ZIF-67/mGOP through an in-situ growth strategy, which was applied to adsorb 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") in wastewater. A combination of characterizations, experiments (pH, humic acid and ion strength effect) and quantum chemical calculations revealed the microscopic adsorption mechanism involves each single component, of which the hydrogen bond (O/N center dot center dot center dot H-O) and pi-pi electron donor acceptor (pi-pi EDA) interactions of mGOP endowed favourable adsorption of ZIF-67/mGOP, and mechanisms of the pore filling and Co-O chelation of ZIF-67 played synergistic effect. Such nanocomposite as a ZIFs-based adsorbent exhibited ultra-high porosity (total pore volume = 0.4033 cm(3)/g) and specific surface area (995.22 m(2)/g), revealed the heterogeneity and multilayer adsorption properties, and obtained a theoretical maximum adsorption capacity of 159.845 mu g/g which higher than that of mZIF-67 alone. Overall, this work provided an effective strategy for rationally modulate ZIFs-based composites and exploration of adsorption mechanism. (c) 2023 Elsevier B.V. All rights reserved.

Psychoactive substances can irreversibly harm human health and threaten ecologic environment after entering the environment. 3D hierarchically porous carbon obtained from magnetic biochar/metal–organic framework (MBC/MOF) has been successfully prepared by changing ZIF-8 and waste biomass ratio. Comprehensive characterization results before and after ketamine adsorption showed the possible adsorption mechanisms including chelation, π-π, H-bond interaction and pore filling. Batch experiments have proved chemical and physical adsorption coexist, in which chemisorption was dominant. π-π interaction and H-bond interaction were confirmed by the humic acid and pH experiments, respectively. Further analysis of Molecular Dynamics simulations indicated that the chelation was stronger than the π-π interaction and H-bond interaction. Specifically, the Zn of ZIF-8 in MBC/MOF acted as a chelating site, the π-π interaction occurred between the graphene-like structure of MBC and the benzene ring of ketamine, the hydrogen bonding interaction was found between the oxygen-rich functional groups of MBC/MOF and the oxygen atoms of ketamine (OH···O). Anion, cation, leaching and cycle experiments indicated the MBC/MOF had outstanding anti-interference ability, high reusability, excellent stability and safety. These findings will broaden the applications of metal organic framework and magnetic biochar in the field of pollutants adsorption.

目的基于RGB色彩模式下的颜色数字化特征,实现黑色书写字迹与红色印章印文朱墨时序的有效鉴别.方法基于统计学中的显著性检验原理,通过Photoshop软件的RGB颜色模式来采集颜色数据,利用SPSS数据软件中Mann-Whitney检验进行数据分析,得到朱墨时序的判定依据.结果基于RGB颜色数字化特征的方法适用于手写文件朱墨时序的判定,但对样本有一定要求.在检材与样本同序对比中,R、G、B需有两个或两个以上的P＞0.05,异序对比中需有两个或两个以上的P＜0.05,即可得出判定结论.结论利用颜色数字化特征能够实现手写文件朱墨时序的有效鉴别,在传统朱墨时序检验方法的基础上,提供数字化无损检验的新方法,为文书物证鉴定领域提供借鉴.

合成了一种磁性还原氧化石墨烯/金属有机框架物(MrGO/ZIF-67)新型纳米碳复合材料,并将其用于甲基苯丙胺(MAMP)的吸附,建立了磁固相萃取/超高效液相色谱-串联质谱法快速测定毛发中MAMP的新方法.分别利用透射电镜、振动样品磁强计(VSM)和傅里叶变换红外光谱对MrGO/ZIF-67进行综合表征,采用单因素实验重点优化溶液pH值,采用Box-Behnken Design考察萃取时间、吸附剂用量、MAMP初始浓度对MAMP吸附性能的影响.得到的最优条件为:溶液pH值11.0、吸附剂用量4 mg,萃取时间20 min,MAMP的初始浓度为110 μg/L.MAMP在1～200 μg/L范围内线性关系良好,相关系数(r2)为0.999 9,检出限(LOD)和定量下限(LOQ)分别为0.188 μg/L和0.572 μg/L.在1.0、5.0、9.6 μg/L加标水平下的回收率为80.2%～94.4%,日内和日间相对标准偏差(RSD,n = 3)分别为1.6%～2.7%和6.0%～8.2%,表明该材料能用于实际毛发中MAMP的检测.

This work designed and synthesized novelly selective, highly efficient and friendly environmental biochar nanomaterial (ZMBC@ChCl-EG) by screening suitable deep eutectic solvent (DES) as the functional monomer via Density Functional Theory (DFT). The prepared ZMBC@ChCl-EG achieved the highly efficient adsorption of methcathinone (MC) and exhibited excellent selectivity as well as good reusability. Selectivity analysis concluded that the distribution coefficient value (K-D) of ZMBC@ChCl-EG towards MC was 3.247 L/g, which was about 3 times higher than that of ZMBC, corresponding to stronger selective adsorption capacity. The studies of isothermal and kinetics indicated that ZMBC@ChCl-EG had an excellent adsorption capacity towards MC and the adsorption was mainly chemically controlled. In addition, DFT was used to calculate the binding energies between MC and each component. The binding energies were -10.57 kcal/mol for ChCl-EG/MC, -3.15 similar to-9.51 kcal/mol for BCs/MC, -2.33 kcal/mol for ZIF-8/MC, respectively, suggesting that DES played a major role in enhancing methcathinone adsorption. Lastly, the adsorption mechanisms were revealed by variables experiment combined with characterizations and DFT calculation. The main mechanisms were hydrogen bonding and pi-pi interaction.

Metal-organic framework (MOF) materials, which have been deemed as effective adsorbents for remov-ing emerging contaminants, suffered from difficult separation that limited their application in water treatment. Two different decorated ZIF-67 multifunctional adsorbents have been successfully fabricated by anchoring ZIF-67 on diverse magnetic substrates. The comparative study combining a series of adsorp-tion experiments and structural characterization analyses was facilitated to explore the adsorption per-formance of two adsorbents (MrGO/ZIF and MZIF). The better adsorption capacity of MrGO/ZIF for methamphetamine (MAMP) was observed. For the introduction of reduced graphene oxide (rGO), ZIF-67 nanocrystals showed stratified multidimensional distribution on rGO, and formed a stepped pore structure. Relatively large pores of MrGO/ZIF were beneficial for the transport and adsorption of MAMP in aqueous phase. The adsorption of MAMP could be described by the Langmuir isotherm and pseudo-second-order kinetic model, and adsorption process was spontaneous and endothermic. Theoretical investigation in combination with analyses of the XPS characterization illustrated that the H-bonding interaction between the Co-OH and-NH of MAMP, and p -p interaction among the heteroaromatic rings in adsorbent and the benzene ring of MAMP was the mainly contribution of driving MAMP adsorption on MrGO/ZIF. Summarily, the excellent adsorption properties of MrGO/ZIF coupled with facile separation and sustainability make MrGO/ZIF remove MAMP more efficiently from water, which provide an insight for contaminated water treatment, and psychoactive substances monitoring.(c) 2022 Elsevier B.V. All rights reserved.

Deep eutectic solvent (DES), an environmentally friendly solvent, has drawn the growing interest of the academic community due to its distinctive physicochemical properties and widespread applications. In this work, magnetic biochar modified with DES (DES-MBC) has been fabricated and utilized to efficiently remove methcathinone from water. Batch experiments and density functional theory (DFT) simulations were utilized to explore the adsorption performance and mechanism of DES-MBC. Under optimal conditions, the removal rates of DES-MBC were highly remarkable with 93.26% and 95.85% in water containing methcathinone of 0.5 mg.L-1 and 1.0 mg.L-1, respectively. DFT simulations revealed that DES incorporation lowered the HOMO-LUMO energy gap (delta E-gap) and introduced additional reaction sites (e. g. hydroxyl groups and quaternary amino groups) which could react with methcathinone to increase the adsorption capacity of DES-MBC. Combining the results of experiments and simulations, the main removal mechanism between methcathinone and DES-MBC were electro-static interaction, hydrogen bond and 7C-7C interaction. In conclusion, DES modification was an effective strategy to enhance the adsorption capacity for methcathinone from water in practical applications. This study will contribute to the deep and extensive understanding of the microscopic adsorption mechanism so as to help optimize and develop more excellent adsorbents.

The corrosion property of 5083 aluminum alloy sheets with different contents of three elements is investigated by SEM,metallographic microscopy,intergranular corrosion test and exfoliation corrosion test.Polarization curves of these samples are measured in EXCO solution.It shows that the anti-corrosion property of alloy is relevant to the content of magnesium element,and the intergranular corrosion and exfoliation corrosion of the 5083 alloy sheet are increased with the increase of magnesium content.The content of manganese has little effect on the corrosion potential,but it can improve the anti-intergranular corrosion and anti-exfoliation corrosion property.

The process schemes of cold roiling and stabilizing treatment for 5083 aluminum alloy were designed using orthogonal method. The effects of cold deformation and stabilizing treatment on corrosion resistance of the alloy were investigated by means of intergranular corrosion test, exfoliation corrosion test and microstructure and morphology observation. Polarization curves of the alloy in exfoliation corrosion solution were measured. The results show that the intergranular corrosion and exfoliation corrosion tendency of the alloy increased with increasing the cold deformation and decreasing the stabilizing treatment temperature. The stabilizing treatment time had little effect. The alloy had the best corrosion resistance after stabilizing treated at 200--220℃ for 2 h with cold deformation of 20 % -- 25 %.