The rising concentration of carbon dioxide (CO2) as one of the greenhouse gases in the atmosphere is a major source of worry. Electrochemical reduction of CO2 is one of many ways to convert CO2 gas ...into usable compounds. An electrochemical technique was applied in this study to reduce CO2 using a boron-doped diamond (BDD) working electrode modified with MXene (Ti3C2Tx) material to improve electrode performance. MXene concentrations of 0.5 mg/mL (MXene-BDD 0.5), 1.0 mg/mL (MXene-BDD 1.0), and 2.0 mg/mL (MXene-BDD 2.0) were drop-casted onto the BDD surface. MXene was effectively deposited on top of the BDD surface, with Ti weight loads of 0.12%, 4.06%, and 7.14% on MXene-BDD 0.5, MXene-BDD 1.0, and MXene-BDD 2.0, respectively. The modified working electrode was employed for CO2 electroreduction with optimal CO2 gas aeration. The existence of the MXene substance in BDD reduced the electroreduction overpotential of CO2. For the final result, we found that the MXene-BDD 2.0 electrode effectively generated the most formic acid product with a maximum reduction potential as low as −1.3 V (vs. Ag/AgCl).
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
In today's world, the utilization of electronic devices, particularly mobile phones, has seen a remarkable surge and they are a valuable source of recovery of precious metals. The current study ...reports on the physical and chemical processing of mobile phone waste into leachate, followed by recovery of precious metals, using ionic liquid functionalized activated carbon (ACF). The recovery process was explored both in batch and column study. The presence of base metals in the final leachate was minimized by employing multi-stage chemical leaching, leading to a more efficient purification process. Moreover, adjustment of HCl concentration in the leachate leads to decreased in other metals interference during adsorption. Following the batch adsorption results, a favorable interaction between IL and metal complexes leads to a quantitative adsorption of the precious metals. In addition, ACF also gave an excellent performance in the column adsorption process with the high bed depth and low flow rate of the leachate as the influential parameter. An increase in the bed depth and a decrease in leachate flow rate proportionally increases the values of kTh (rate constant), qe (adsorption capacity), and KYN (rate constant) and positively increases the 50% breakthrough time (τ). Moreover, the final purification of the adsorbed metals was performed selectively through sequential desorption, employing Na2S2O3, NH4SCN, and HNO3 solutions. Finally, the adsorption capability of ACF shown a negligible change after five repetitive adsorption-desorption cycles. Thus, the current study presents a method to process mobile phone waste and selectively recover the precious metals from the leachate.
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•Activated carbon from palm kernel shell was functionalized with ionic liquid.•Mobile phone waste was physically and chemically process to extract precious metals.•ACF was able recover Au from a mobile phone leachate in batch and continuous system.•The separation of precious metals was done by sequential desorption.•ACF was able to maintain performance in a three adsorption-desorption cycles.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Bub1 is a serine/threonine kinase proposed to function centrally in mitotic chromosome alignment and the spindle assembly checkpoint (SAC); however, its role remains controversial. Although it is ...well documented that Bub1 phosphorylation of Histone 2A at T120 (H2ApT120) recruits Sgo1/2 to kinetochores, the requirement of its kinase activity for chromosome alignment and the SAC is debated. As small-molecule inhibitors are invaluable tools for investigating kinase function, we evaluated two potential Bub1 inhibitors: 2OH-BNPPI and BAY-320. After confirming that both inhibit Bub1
, we developed a cell-based assay for Bub1 inhibition. We overexpressed a fusion of Histone 2B and Bub1 kinase region, tethering it in proximity to H2A to generate a strong ectopic H2ApT120 signal along chromosome arms. Ectopic signal was effectively inhibited by BAY-320, but not 2OH-BNPP1 at concentrations tested. In addition, only BAY-320 was able to inhibit endogenous Bub1-mediated Sgo1 localization. Preliminary experiments using BAY-320 suggest a minor role for Bub1 kinase activity in chromosome alignment and the SAC; however, BAY-320 may exhibit off-target effects at the concentration required. Thus, 2OH-BNPP1 may not be an effective Bub1 inhibitor
, and while BAY-320 can inhibit Bub1 in cells, off-target effects highlight the need for improved Bub1 inhibitors.
In this modern time, precious metals hold an important place in human life. Secondary resources, such as waste, have become an essential alternative source to supplant these precious metals. Ionic ...liquids (ILs) have demonstrated excellent performance in recovering precious metals. Immobilizing ILs onto a solid support such as mesoporous silica simultaneously diminishes the IL drawback, enhances support adsorption capacity, and improves reusability. Thus, chemically enhanced mesostructured silica nanoparticles with trioctylodecylphosphonium chloride (P8Cl_MSN) may provide a superior adsorbent for Pd(II) from an aqueous solution. P8Cl_MSN shows a high adsorption capacity in batch and fixed-bed adsorption, 264 and 213 mg g–1, respectively. The adsorption Pd(II) fits with the Langmuir isotherm model (R 2 = 0.998) and is chemisorbed onto the P8Cl_MSN. Pd(II) adsorption fits (R 2 = 0.999) with the pseudo-second-order kinetic model. The continuous adsorption of Pd(II) fits (R 2 = ∼0.99) with the Thomas and Yoon–Nelson model. Pd(II) desorption (98%) is achieved using CS(NH2)2 in 100 min, and P8Cl_MSN also shows excellent reusability performance and selectivity.
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IJS, KILJ, NUK, PNG, UL, UM
Electronic waste has become a global concern, as it has been steadily increasing over the years. The lack of regulation and appropriate processing facilities has rendered these wastes an ...environmental hazard. However, they represent excellent alternative sources of precious metals, which are highly in demand in various industries. Adsorption has been a popular method for metal removal/recovery because of several advantages, such as ease of use and low cost. In this regard, it is crucial to develop an inexpensive and functionalized adsorbent to selectively adsorb precious metals. Thus, silica, which is derived from rice husk and is abundantly present in Indonesia, was functionalized using an ionic liquid (SiRH_Im) and used for Au(III) adsorption from a simulated mobile phone leach liquor. SiRH_Im exhibited a high adsorption capacity (232.5 mg g-1). The Au(III) adsorption kinetic suitably fitted with the pseudo-second-order kinetic model. The Au(III) adsorption followed a chemisorption route that suited the monolayer model. Thomas' and Yoon-Nelson's models were well suited for the continuous Au(III) behavior. Selective recovery of Au(III) from SiRH_Im was achieved via sequential desorption. SiRH_Im also showed excellent reusability, as indicated by a negligible decrease in adsorptive performance over three cycles. The functionalization of silica derived from rice husk using an ionic liquid led to the successful creation of a solid adsorbent with a high adsorption capacity toward precious metals present in a simulated leach solution. Our results highlight the benefit of the functionalization of biomass through the immobilization of an ionic liquid toward the enhancement of its adsorption capability.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The search for materials for next-generation spintronic applications has witnessed exponentially increasing interest, mainly due to the explosive development of numerous two-dimensional (2D) ...materials discovered in the last decade. Among them, MXenes have emerged as promising candidates for many applications due to their unique and versatile tunability in structure and properties. In particular, their excellent combination of conductivity and highly charged surfaces leads to outstanding electrochemical properties that are significant in electronic applications. Moreover, the ease of modifying the atomic and electronic structures, and thus the functionalities of MXenes, further opens up the opportunity to realize MXenes-based spintronic device applications. The explosive development of MXenes, such as tuning the bandgap and enhancing their magnetic properties, could pave the way for the integration of MXenes in device configurations suitable for spintronics. In this article, we provide an overview of the potential applications of MXenes with a special focus on spintronic device applications. We commence the discussion with various fundamental aspects of spintronics, including the understanding of materials for spintronics in general, MXenes, and their fabrication, followed by presenting perspectives on plausible strategies and future challenges in integrating MXenes into spintronic devices.
The explosive development of MXenes for example by tuning the bandgap and wakening their magnetic properties could simply pave the way for the integration of MXenes in device configurations suitable for spintronic devices.
Reductive cyclizations of carbonyl compounds, mediated by samarium(II) diiodide (SmI2, Kagan’s reagent), represent an invaluable platform to generate molecular complexity in a stereocontrolled ...manner. In addition to classical ketone and aldehyde substrates, recent advances in radical chemistry allow the cyclization of lactone and lactam-type substrates using SmI2. In contrast, acyclic esters are considered to be unreactive to SmI2 and their participation in reductive cyclizations is unprecedented. Here, we report a diastereoselective radical 1,4-ester migration process, mediated by SmI2, that delivers stereodefined alkene hydrocarboxylation products via radical cyclization of acyclic ester groups in α-carbomethoxy δ-lactones. Isotopic labeling experiments and computational studies have been used to probe the mechanism of the migration. We propose that a switch in conformation redirects single electron transfer from SmI2 to the acyclic ester group, rather than the “more reactive” lactone carbonyl. Our study paves the way for the use of elusive ketyl radicals, derived from acyclic esters, in SmI2-mediated reductive cyclizations.
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IJS, KILJ, NUK, PNG, UL, UM
Bub1 is a serine/threonine kinase proposed to play a role in the Spindle Assembly Checkpoint (SAC) and chromosome alignment. However, its role remains controversial. Bub1 kinase is suggested to have ...two substrates, histone 2A (H2A) and Cdc20, and inhibits the anaphase process before all kinetochores bind to microtubules in the mitosis cycle. Bub1 kinase was also discovered to be a major kinase that provides a scaffold protein to recruit other SAC proteins and could be used as a target to cure cancer. Two Bub1 kinase inhibitors based on the pyrazole core, cyclopropylbenzylpyrazole (BAY-320) and methoxybenzylpyrazole (BAY-524), have been synthesised by Hitchcock et al. The cyclopropylbenzylpyrazole showed selective binding to Bub1 kinase in assays, therefore the synthesis of the Bub1 kinase inhibitor could be used as a tool to address the role of Bub1 kinase. Synthesis of cyclopropylbenzylpyrazole in eight steps was achieved using the route and modified procedures of Hitchcock et al. The approach involves several steps: 1) a Weinreb amide to form a ketone; 2) 1,3-dicarbonyl formation and condensation to generate a pyrazole; 3) amidine formation; 4) pyrimidine ring formation; and 5) palladium-catalyzed Buchwald-Hartwig amination. The biological assay activity showed that Bub1 kinase activity is not essential for SAC function, but it did suggest that Bub1 plays a role in the scaffolding of SAC proteins. Comparison with another Bub1 kinase inhibitor, 2OH-BNPP1, showed that cyclopropylbenzylpyrazole (BAY-320) could inhibit Bub1 kinase activity in vitro and in vivo by inhibition of H2A phosphorylation, Sgo1 delocalisation and colony growth, whereas the 2OH-BNPP1 could only inhibit in vitro.Anticancer agent, BGC945, inhibits Thymidilate Synthase (TS). We proposed to synthesise the cyclopentagquinazalone core of BGC945 using a new strategy based around a SmI2-mediated step. It was proposed that BCG945's core could be generated from a cyclopropyl benzoate substrate using a cascade reaction mediated by SmI2. However, after the formation of key starting materials, a cyclopropane, an a,b-unsaturated ketone and an alkyl halide, and many synthesis attempts, we could not generate the core of target compound.Building on our studies with SmI2, we discovered an unprecedented SmI2-mediated 1,4-ester shift that proceeds via the 5-exo trig cyclisation of a ketyl radical formed from an ester by SmI2. A five step synthesis was carried out to generate lactone substrates. The route started from dimethyl malonate and involved a Michael addition, cross metathesis, and SmI2-H2O-mediated ketone reaction. The novel 1,4-ester shift was mediated by SmI2-HMPA-H2O. The scope has been explored and the 1,4-ester shift was seen to proceed in moderate to good yield and with complete diastereocontrol. The substituent at the 5-position of the lactone ring is thought to play a key role in controlling the conformation of the lactone and favouring the 1,4-ester shift.
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