RSC Advances

Han, Xiao-Le; Li, Qingyu; Hao, Hao; Liu, Chenyin; Li, Run; Yu, Fan; Lei, Jiawen; Jiang, Qingqing; Liu, Yi; Hu, Juncheng

doi: 10.1039/c9ra09840bpmid: 35497204

Water-soluble AgInZnS quantum dots (AIZS QDs) were synthesized with glutathione (GSH) as a stabilizer by a facile one-step method based on a hydrothermal reaction between the nitrate salts of the corresponding metals and sodium sulfide as a sulfide precursor at 110 °C. The optimal reaction conditions (temperature, time, pH, and the molar ratios of the precursors) were studied. According to the data from TEM, XPS, and XRD, AIZS QDs were characterized with excellent optical properties. The results showed that the aqueous-dispersible AIZS QDs were quasi-spherical and their average diameter was 3.51 nm. Furthermore, the cytotoxicity of AIZS QDs was investigated by microcalorimetry and microscopy techniques (confocal microscopy and TEM). The data revealed that AIZS QDs exhibited low toxicity, biocompatibility, and good water stability, due to which they could be used as a fluorescent probe for bioimaging and labeling. In addition, AIZS QDs could be used as a sensor to detect Cu2+ because the fluorescence of AIZS QDs was quenched by Cu2+.

Turksoy, Abdurrahman; Yildiz, Deniz; Aydonat, Simay; Beduk, Tutku; Canyurt, Merve; Baytekin, Bilge; Akkaya, Engin U.

doi: 10.1039/d0ra00831apmid: 35497229

Controlled generation of singlet oxygen is very important due to its involvement in scheduled cellular maintenance processes and therapeutic potential. As a consequence, precise manipulation of singlet oxygen release rates under mild conditions, is crucial. In this work, a cross-linked polyacrylate, and a polydimethylsiloxane elastomer incorporating anthracene-endoperoxide modules with chain extensions at the 9,10-positions were synthesized. We now report that on mechanical agitation in cryogenic ball mill, fluorescence emission due to anthracene units in the PMA (polymethacrylate) polymer is enhanced, with a concomitant generation of singlet oxygen as proved by detection with a selective probe. The PDMS (polydimethylsiloxane) elastomer with the anthracene endoperoxide mechanophore, is also similarly sensitive to mechanical force.

Feng, Hui; Tang, Jingwen; Chen, Haotian; Tian, Yuanyuan; Fang, Qihong; Li, Jia; Liu, Feng

doi: 10.1039/d0ra00518epmid: 35497251

Using large-scale molecular dynamics (MD) simulations, the effects of interface and layer number in the nanoindentation response of experimentally observed nanotwinned Cu/high entropy alloy (HEA) FeCoCrNi nanolaminate are studied. The dislocations are nucleated and emitted, which are more limited to the first twinning layer > second twinning layer > HEA layer. The stacking fault strengthening is pronounced due to the obvious difference of stacking fault energy between Cu and HEA, which can be rarely observed from the previous work in traditional alloys and metals. After the indentation induced deformation, the nanotwinned Cu/HEA FeCoCrNi nanolaminates for different layer numbers generate a mass of Shockley partial dislocations to cause the good plasticity, attributed to the strong strain gradient effect. The strong layer number and interface structure effects found here can provide insight for the design of advanced nanolaminate with high strength and good plasticity.

Pan, Yanfang; Chen, Lan; Pang, Lingling; Chen, Xiaotong; Jia, Xiaoyu; Li, Xihong

doi: 10.1039/c9ra06418dpmid: 35497218

Controlling browning and mitigating oxidative damage are important factors when attempting to extend the shelf-life and high-quality features of fresh-cut sweet potato (Ipomoea batatas (L.) Lam). In order to preserve the color and antioxidant capacity, ultrasound (US) treatment at 40 kHz for 10 min was applied to investigate the effect on enzymatic browning of sweet potato slices. Changes in color, total phenolic content, total antioxidant capacity, phenol metabolism-related enzymes including phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), peroxidase (POD) were examined. Also investigated here were superoxide radical (O2−˙) and hydrogen peroxide (H2O2) contents, antioxidant enzymes including superoxide dismutase (SOD) and catalase (CAT) involved in reactive oxygen species metabolism. After storage lasting 10 days at 4 °C, US-treated slices maintained significantly (p < 0.05) higher luminosity (p = 0.000003) and chroma (p = 0.000018) by reducing PPO and POD activities, when compared to the control. Meanwhile, the induction of PAL was observed to positively correlate with higher total phenolic content (r = 0.818, p < 0.01; p = 6.1752 × 10−9), thereby enhancing antioxidant capacity to combat oxidative damage. Moreover, O2−˙ (p = 3.8046 × 10−10) and H2O2 (p = 0.000013) concentrations were significantly (p < 0.05) suppressed by activating CAT and SOD activities. Results suggested that US treatment could inhibit browning of fresh-cut sweet potato by reducing the activity of PPO and POD while improving total antioxidant capacity.

Li, Shuping; Yang, Xichuan; Zhang, Li; An, Jincheng; Cai, Bin; Wang, XiuNa

doi: 10.1039/c9ra09693kpmid: 35497242

Two D–π–A′–π–A organic dyes with triazatruxene (TAT) as the electron donor, thiophene as the π-spacer, benzoic acid as the anchor group, and benzothiadiazole (BT) or difluorobenzo[c][1,2,5]thiadiazole (DFBT) as the additional acceptor, namely LS101 and LS102, respectively, were applied to dye-sensitized solar cells (DSSCs). As fluorine substituents are usually strong electron-withdrawing groups, introducing two fluorine atoms into BT was expected to strengthen the electron-withdrawing ability of the auxiliary acceptor, resulting in DSSCs with a broader light capture region and further improved power conversion efficiency (PCE). Fluorine is the smallest electron-withdrawing group with an induction effect, but can also act as an electron-donating group owing to its conjugation effect. When the conjugation effect is dominant, the electron-withdrawing ability of additional acceptor DFBT decreases instead. Accordingly, the band gap of LS102 was broadened and the UV-vis absorption spectrum was blue-shifted. In the end, DSSCs based on LS101 achieved a champion PCE of 10.2% (Jsc = 15.1 mA cm−2, Voc = 966 mV, FF = 70.1%) while that based on LS102 gave a PCE of only 8.6% (Jsc = 13.4 mA cm−2, Voc = 934 mV, FF = 69.1%) under standard AM 1.5G solar irradiation (100 mW cm−2) with Co2+/Co3+ as the electrolyte.

Lian, Zheng; Wei, Chaohui; Gao, Bin; Yang, Xiaogang; Chan, Yue; Wang, Jing; Chen, George Zheng; Koh, Kai Seng; Shi, Yong; Yan, Yuying; Ren, Yong; He, Jun; Liu, Fu

doi: 10.1039/c9ra10899hpmid: 35497220

The highly efficient treatment of azo dye contaminated wastewater from the textile industry is an important but challenging problem. Herein, polydimethylsiloxane (PDMS) microparticles, incorporating multiple-walled carbon nanotubes/titanium dioxide (MWCNTs/TiO2) nanocomposites, were successfully synthesized to treat wastewater containing Rhodamine B (RhB) dyes in a synergetic approach, by combining sorption and photocatalytic degradation. The surfactant wrapping sol–gel method was applied to synthesize MWCNTs/TiO2 nanocomposites with TiO2 nanoparticles evenly distributed on the surface of the MWCNTs. The PDMS microparticles were fabricated with an oil-in-water (O/W) single emulsion template, using needle-based microfluidic devices. MWCNTs/TiO2 nanocomposites (at a weight ratio of 1%, and 2%, respectively) were mixed with the PDMS precursor as the dispersed phase, and an aqueous solution of polyvinyl alcohol (PVA) was used as the continuous phase. Highly monodispersed microparticles, with average diameters of 692.7 μm (Coefficient of Variation, CV = 0.74%) and 678.3 μm (CV = 1.04%), were formed at an applied flow rate of the dispersed and continuous phase of 30 and 200 μL min−1, respectively. The fabricated hybrid microparticles were employed for the treatment of RhB, involving a dark equilibrium for 5 hours and UV irradiation for 3 hours. The experimental conditions of applied PDMS type, mass loading amount, treatment duration, photodegradation kinetics, initial concentration of pollutants and environmental pH values were investigated in this work. The PDMS microparticles with 2 wt% MWCNTs/TiO2 nanocomposites can exhibit a removal efficiency of 85%. Remarkably, an efficiency of 70% can be retained after the microparticles have been recycled and reused for 3 cycles. The PDMS–MWCNTs/TiO2 microparticles possess a superior performance over conventional treatment approaches for dye contaminated wastewater, especially in recyclability and the prevention of secondary pollution. This work provides a feasible and eco-friendly route for developing an efficient and low-cost microfluidic method for treating complicated water environmental systems.

He, Kai-Qiang; Yuan, Chun-Gang; Shi, Meng-Dan; Jiang, Yang-Hong; Yu, Su-Juan

doi: 10.1039/c9ra08481apmid: 35497216

Sequential extraction has been validated as an effective method to assess the fractions of elements in fly ash. However, the time consumption and high labor costs limit the application of the conventional sequential extraction (CSE) for fast screening of elemental fractions in fly ash. In this study, two ultrasound-assisted sequential extraction (UASE) methods were developed for fast analysis of arsenic (As) and selenium (Se) fractions in fly ash (FA). The parameters of UASE were optimized by comparing the results of As and Se obtained from UASE with those values observed via CSE. The operation time of sequential extraction procedures for As and Se were shortened from 24.5 h to less than 90 min. A certified reference material (CRM, GBW08401) and real fly ash samples were applied to validate the developed UASE. The recoveries of As and Se were found in the range of 82.3% to 114%. For all fractions, the performance of UASE was faster than CSE with the acceptable uncertainties. The analytical results demonstrated that the concentration of As in F3 was found to be higher than other fractions, while the main forms of Se were found to be in F1 and F3 in the fly ash samples. Based on the advantages of high efficiency and easy operation, the developed UASE procedures can be applied for fast screening of the mobility and bioavailability of As and Se in FA from coal fired power plants.

Dadhwal, Sumit; Fairhall, Jessica M.; Hook, Sarah; Gamble, Allan B.

doi: 10.1039/d0ra01013hpmid: 35497212

The synthesis of a bioorthogonal-responsive low molecular weight diphenylalanine (PhePhe)-based hydrogel that is capped with a 4-azido-2,3,5,6-tetrafluorobenzyl carbamate self-immolative linker is reported. The hydrogelator (AzF4-PhePhe) generates a stable hydrogel at 0.1 wt%, and rapidly reacts with the bioorthogonal reagent trans-cyclooctene (TCO), inducing a gel-to-solution transition. The critical gel concentration is five-fold lower than our previously synthesized non-fluorinated hydrogelator (Az-PhePhe), and the minimum concentration of TCO required for visible gel-to-solution transition in 24 hours is 1 mM. Doxorubicin can be encapsulated in the hydrogel and TCO-triggered dissolution results in 76% and 89% release after 10 and 24 hours, respectively. Compared with our non-substituted aryl azide capping group used for Az-PhePhe, the tetrafluorinated aryl azide group improves the stability of the hydrogel in unbuffered water at a lower critical gel concentration, while improving sensitivity towards the bioorthogonal reagent TCO.

Kamran, Urooj; Heo, Young-Jung; Min, Byung-Gak; In, Insik; Park, Soo-Jin

doi: 10.1039/c9ra10277apmid: 35497234

Novel and effective reduced graphene oxide–nickel (Ni) doped manganese oxide (RGO/Ni-MnO2) adsorbents were fabricated via a hydrothermal approach. The reduction of graphite to graphene oxide (GO), formation of α-MnO2, and decoration of Ni-MnO2 onto the surface of reduced graphene oxide (RGO) were independently carried out by a hydrothermal technique. The physical and morphological properties of the as-synthesized adsorbents were analyzed. Batch adsorption experiments were performed to identify the lithium uptake capacities of adsorbents. The optimized parameters for Li+ adsorption investigated were pH = 12, dose loading = 0.1 g, Li+ initial concentration = 50 mg L−1, in 10 h at 25 °C. It is noticeable that the highest adsorption of Li+ at optimized parameters are in the following order: RGO/Ni3-MnO2 (63 mg g−1) > RGO/Ni2-MnO2 (56 mg g−1) > RGO/Ni1-MnO2 (52 mg g−1). A Kinetic study revealed that the experimental data were best designated pseudo-second order for each adsorbent. Li+ desorption experiments were performed using HCl as an extracting agent. Furthermore, all adsorbents exhibit efficient regeneration ability and to some extent satisfying selectivity for Li+ recovery. Briefly, it can be concluded that among the fabricated adsorbents, the RGO/Ni3-MnO2 exhibited the greatest potential for Li+ uptake from aqueous solutions as compared to others.

Satpati, Sanjoy; Saha, Sourav Kr.; Suhasaria, Aditya; Banerjee, Priyabrata; Sukul, Dipankar

doi: 10.1039/c9ra07982cpmid: 35497198

Herein, two Schiff base derivatives of vanillin and divanillin with 2-picolylamine, namely, 2-methoxy-4-((pyridin-2-ylmethylimino)methyl)phenol (compound A) and 3,3′-dimethoxy-5,5′-bis-((pyridin-2-ylmethylimino)methyl)-[1,1′-biphenyl]-2,2′-diol (compound B), respectively, were synthesized. Additionally, their adsorption characteristics and corrosion inhibition behavior were compared for mild steel in 1 M HCl using electrochemical impedance spectroscopy, potentiodynamic polarization and weight loss methods. Compound B was found to impart a better anti-corrosive effect (around 95% inhibition efficiency at 313 K) than compound A. The inhibitors act as effective mixed-type inhibitors and exhibit Langmuir-type adsorption behaviour. The kinetic–thermodynamic parameters together with the data obtained from density functional theory (DFT) and molecular dynamics (MD) simulations illustrate the mechanism of corrosion and mode of adsorption of both inhibitors on the metal surface. The better corrosion mitigation propensity of the dimeric form of the inhibitor (compound B) over the monomeric form (compound A) was tested experimentally and explained according to the theoretical data.