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Constructed on the moiety of a lactam screw ring, a near-infrared fluorescent probe RCya for Pd[sup.2+] was designed under the PET mechanism and synthesized by incorporating 2,4-dihydroxybenzaldehyde as the recognition group. Dynamic detection of aqueous Pd[sup.2+] by the probe RCya could be accomplished through ion competition, linear response, fluorescence-pH/time stabilities, and other optical tests. Moreover, the high selectivity, low cytotoxicity, cell permeability, and lysosome accumulation properties of RCya enabled the imaging applications on solid-state RCya–PAN composite nanofibers and in living cells. The recognition mechanism of probe RCya toward Pd[sup.2+] was further studied through simulation calculation and MS analysis.

Constructed on the moiety of a lactam screw ring, a near-infrared fluorescent probe RCya for Pd2+ was designed under the PET mechanism and synthesized by incorporating 2,4-dihydroxybenzaldehyde as the recognition group. Dynamic detection of aqueous Pd2+ by the probe RCya could be accomplished through ion competition, linear response, fluorescence-pH/time stabilities, and other optical tests. Moreover, the high selectivity, low cytotoxicity, cell permeability, and lysosome accumulation properties of RCya enabled the imaging applications on solid-state RCya–PAN composite nanofibers and in living cells. The recognition mechanism of probe RCya toward Pd2+ was further studied through simulation calculation and MS analysis.

Palladium(Pd)-based catalysts have been broadly applied in modern industry. The ideal ones should be robust enough against leaching, load Pd to the maximum degree, and possess outstanding dispersity against aggregation. As for SiO 2 -supported Pd catalysts, aminosilane coupling reagents have been commonly utilized to introduce interfacial self-assembled layers which can chemically bond SiO 2 substrates with siloxy (-SiOH) groups and firmly link Pd with amino groups. However, up to now, the influences of variable aminoalkyl chains on physicochemical properties and catalytic performances of palladium ions (Pd(II)) supported by dendritic mesoporous silica nanospheres (DMSNs) have not been contrasted and revealed. In this work, three types of aminosilane-functionalized DMSNs-based Pd(II) catalysts have been prepared, including DMSNs-1N-Pd(II) within mono-amino group, DMSNs-2N-Pd(II) with di-amino, and DMSNs-3N-Pd(II) with tri-amino ones. For the first time, the effects of mono-, di- and tri-aminosilanes on their basic properties have been thoroughly exploited, including the morphologies, architectures, compositions of crystal phases, surface functional groups, loading contents of Pd, Pd(II) and Pd(0) percentages, etc. Moreover, catalytical performances have been evaluated by Pd-catalyzed Heck reaction as well.

The separation and recovery of precious metals from secondary resources is an extremely important and challenging task. Herein, a novel sorbent is successfully prepared by chemical grafting and utilized for the extraction and separation of Pd(II) ions from aqueous solutions. Various characterization techniques, including Fourier transform infrared spectroscopy, scanning electron microscopy, Brunauer–Emmett–Teller, X-ray photoelectron spectroscopy, and element analysis, are employed to study the structure, morphology, porous nature, and chemical composition of the as-prepared SiO2@GO-SH nanocomposites. The adsorption of Pd(II) ions on the SiO2@GO-SH can be described by the pseudo-second-order model and Langmuir isotherm model. The adsorption equilibrium has been attained within 90 min and the maximum adsorption capacity of 423.2 mg g−1 was attained at pH 3.5 and T = 308 K. The results reveal that SiO2@GO-SH exhibits an excellent adsorption performance towards Pd(II) ions. In addition, we have proposed the adsorption mechanism for Pd(II) ions on the SiO2@GO-SH surface. The adsorption of Pd(II) in SiO2@GO-SH is a chemisorption process, where partial adsorbed Pd(II) ions are reduced to Pd(0) by functional groups (-SH) in the SiO2@GO-SH. The results indicate that SiO2@GO-SH can serve as a promising sorbent for the efficient separation and recovery of palladium from the palladium-containing secondary resources.

Selective metal ions’ extraction and recovery has various applications in the analytical field. Metal ions need to be extracted, detected, and quantified. For that purpose, ion‐imprinted polymers have earned a great deal of attention during the past two decades. Pd2+ ion‐imprinted hollow silica particles including an isatin Schiff base were prepared by Schiff base condensation of (3‐aminopropyl)triethoxysilane and isatin. The prepared Schiff base ligand was coordinated to the target Pd2+ cations, the polymerizable Pd‐complex was set aside to form gel in the company of tetraethoxysilane and the target Pd2+ cations were subsequently removed from the cross‐linked silica network by means of acidified thiourea solution. All materials throughout this synthesis process were investigated utilizing mass spectrometry, elemental analysis, FTIR, and 1H‐NMR. The morphological structure of both Pd2+ ion‐imprinted and non‐ion‐imprinted silica polymer were pictured by scanning electron microscopy. Several batches were studied exploiting both Pd2+ ion‐imprinted and non‐ion‐imprinted silica polymer to test their functionality for selective extraction of Pd2+ cations in multi‐ionic solution of Ni2+, Co2+, Cu2+, Mn2+, and Pd2+.

Replacing alkaline for alkaline-earth metal hydroxide in the synthesis gel during the synthesis of siliceous SSZ-13 zeolite (Si/Al~10) yields SSZ-13 with novel, advantageous properties. Its NH4-form ion-exchanges higher amount of isolated divalent M(II) ions than the conventional one: this is the consequence of an increased number of Al pairs in the structure induced by the +2 charge of Sr(II) cations in the synthesis gel that force two charge-compensating AlO4− motives to reside closer together. We characterize the +2 state of Co(II) ions in these materials with infra-red spectroscopy and X-ray absorption spectroscopy measurements and show their utility for NOx pollutant adsorption from ambient air: the ones derived from SSZ-13 with higher Al pair content contain more isolated cobalt(II) and, thus, perform better as ambient-air NOx adsorbers. Notably, Co(II)/SSZ-13 with an increased number of Al pairs is significantly more hydrothermally stable than its NaOH-derived analogue. Loading Pd(II) into Co-SSZ-13(Sr) produces an active NOx adsorber (PNA) material that can be used for NOx adsorption from simulated diesel engine exhaust. The critical issue for these applications is hydrothermal stability of Pd-zeolites. Pd/SSZ-13 synthesized in the presence of Sr(OH)2 does not lose its PNA capacity after extremely harsh aging at 850 and 900 °C (10 h in 10% H2O/air flow) and loses only ~55% capacity after hydrothermal aging at 930 °C. This can be extended to other divalent metals for catalytic applications, such as copper: we show that Cu/SSZ-13 catalyst can survive hydrothermal aging at 920 °C without losing its catalytic properties, metal dispersion and crystalline structure. Thus, we provide a new, simple, and scalable strategy for making remarkably (hydro)thermally stable metal-zeolite materials/catalysts with a number of useful applications.

Literature thermodynamic data on species and particles existing in the heterogeneous PdO-H 2 O system were checked for consistency, and the equilibrium constants for dissolution of palladium oxide and hydroxide in water and for Pd 2+ (aq) hydrolysis were recommended. Δ f G 298.15 ° obtained in this work for Pd 2+ (aq) sharply differs (no less than by 6 kJ/mol) from values that are reported in fundamental thermodynamic reference books and based on experimentally measured palladium electrode potential at 25°C. Detailed examination of literature data on the thermodynamic properties of compounds in the Cl-Pd(aq) system is required to account for revealed inconsistency.

X703; 采用沉淀聚合法,以PdCl42-为模板,以4-乙烯基吡啶(4-VP)、2-烯丙巯基烟酸(ANA)、2-乙酸胺基丙烯酸(AAA)为功能单体,加入交联剂二甲基丙烯酸乙二醇酯(EGDMA)、引发剂偶氮二异丁腈(AIBN)和致孔剂甲醇,制备钯离子印迹聚合物.通过添加不同种类、用量的功能单体和不同用量的交联剂,探究不同制备条件对钯离子印迹聚合物制备效果的影响.优化结果表明,与ANA和AAA功能单体对比,4-VP和PdCl42-能形成4∶1的稳定配合物,结合常数最大,印迹效果最好,是3种功能单体中用于制备钯离子印迹聚合物的最佳选择.吸附试验结果进一步表明,按照模板、功能单体、交联剂用量比例为1∶4∶40制备的钯离子印迹聚合物对Pd(Ⅱ)的吸附量最大,为5.042 mg/g.

Low concentrations of Pt and Pd in in-dustrial (mug g-1 level) and environmental samples (mug g-1 level) together with the complexity of the matrix causing many interferences during the determination of noble metals often require elaboration and application of pre-concentration/matrix separation procedures before detection of the analyte. Different pre-concentration/matrix separation procedures applied prior to the determination of Pt and Pd by atomic spectrometric techniques are reviewed and critically compared taking into account potential interferences. The methods studied are divided into 5 groups including precipitation and coprecipitation, liquid-liquid extraction, solid phase extraction, electrochemical pre-concentration and biosorption. The main analytical problems occuring during sample preparation and storage are discussed.