Photocatalytic coatings based on a zinc(ii) phthalocyanine derivative immobilized on nanoporous gold leafs with various pore sizes

A series of singlet oxygen sensitizing hybrid materials is reported consisting of a zinc(ii) phthalocyanine (ZnPc) derivative immobilized on nanoporous gold leafs (npAu) with various pore sizes. The resulting photocatalytic coatings exhibit a thickness of around 100 nm and pore sizes between 9–50 nm. Herein, we report the synthesis and characterization of those hybrid materials which were synthesized by functionalization of npAu leafs by an azide terminated alkanethiol self-assembled monolayer (SAM) and subsequent copper catalyzed azide–alkyne cycloaddition (CuAAC). The characterization of the samples morphology included scanning electron microscopy (SEM), UV-Vis spectroscopy as well as energy dispersive X-ray spectroscopy (EDX). The morphology–reactivity relationship was investigated employing the hybrid photocatalysts in the photooxidation of diphenylisobenzofuran (DPBF) as selective singlet oxygen quencher. An increasing photocatalytic activity was found for smaller pore sizes up to 15 nm, due to the gain in specific surface area concomitant with an increasing amount of immobilized photosensitizer, completely dominating the effect of the higher spectral overlap caused by the shift of the plasmon resonance of npAu, until mass transport and diffusion limitation gets predominant for pore sizes below 15 nm.

A series of hybrid materials consisting of a zinc(ii) phthalocyanine derivative immobilized on nanoporous gold leafs with various pore sizes was prepared and investigated regarding its singlet oxygen sensitization activity.     

Simple and sensitive colorimetric sensors for the selective detection of Cu(ii)

A simple, sensitive colorimetric probe for detecting Cu(ii) ions with fast response has been established with a detection limit of 2.82 μM. UV-Vis spectroscopy along with metal ion response, selectivity, stoichiometry, competition was investigated. In the presence of copper(ii), the UV-Vis spectrum data showed significant changes and the colorimetric detection showed a color change from colorless to yellow. After the selective binding of receptor L with Cu(ii), the UV-visible absorption at 355 nm decreased dramatically, a new absorbance band appeared at 398 nm and its intensity enhanced with the increase in the amount of Cu(ii). Moreover, it exhibited highly selective and sensitive recognition towards Cu(ii) ions in the presence of other cations over the pH range of 7–11. The complex structure was verified by FT-IR spectroscopy, elemental analysis and quantum mechanical calculations using B3LYP/6-31G(d) to illustrate the complex formation between L and Cu(ii). According to the Job plot and the quantum mechanical calculations, the stoichiometric ratio for the complex formation was proposed to be 1 : 1.

Cu(ii) ion with L led to a rapid and sensitive color change from colorless to yellow.     

A highly selective pyridoxal-based chemosensor for the detection of Zn(ii) and application in live-cell imaging; X-ray crystallography of pyridoxal-TRIS Schiff-base Zn(ii) and Cu(ii) complexes

In a simple, one-step reaction, we have synthesized a pyridoxal-based chemosensor by reacting tris(hydroxymethyl)aminomethane (TRIS) together with pyridoxal hydrochloride to yield a Schiff-base ligand that is highly selective for the detection of Zn(ii) ion. Both the ligand and the Zn(ii) complex have been characterized by ¹H & ¹³C NMR, ESI-MS, CHN analyses, and X-ray crystallography. The optical properties of the synthesized ligand were investigated in an aqueous buffer solution and found to be highly selective and sensitive toward Zn(ii) ion through a fluorescence turn-on response. The competition studies reveal the response for zinc ion is unaffected by all alkali and alkaline earth metals; and suppressed by Cu(ii) ion. The ligand itself shows a weak fluorescence intensity (quantum yield, Φ = 0.04), and the addition of zinc ion enhanced the fluorescence intensity 12-fold (quantum yield, Φ = 0.48). The detection limit for zinc ion was 2.77 × 10⁻⁸ M, which is significantly lower than the WHO''s guideline (76.5 μM). Addition of EDTA to a solution containing the ligand–Zn(ii) complex quenched the fluorescence, indicating the reversibility of Zn(ii) binding. Stoichiometric studies indicated the formation of a 2 : 1 L₂Zn complex with a binding constant of 1.2 × 10⁹ M⁻² (±25%). The crystal structure of the zinc complex shows the same hydrated L₂Zn complex, with Zn(ii) ion binding with an octahedral coordination geometry. We also synthesized the copper(ii) complex of the ligand, and the crystal structure showed the formation of a 1 : 1 adduct, revealing 1-dimensional polymeric networks with octahedral coordinated Cu(ii). The ligand was employed as a sensor to detect zinc ion in HEK293 cell lines derived from human embryonic kidney cells grown in tissue culture which showed strong luminescence in the presence of Zn(ii). We believe that the outstanding turn-on response, sensitivity, selectivity, lower detection limit, and reversibility toward zinc ion will find further application in chemical and biological science.

The synthesis, characterization, X-ray crystallography, and live-cell imaging of pyridoxal-TRIS Schiff-base ligand which is selective as a luminescence sensor to detect Zn(ii) ion, and the corresponding Zn(ii) and Cu(ii) complexes are described.     

Gro许旺细胞在不同孔径丝素蛋白支架上的生长(英文)

背景:细胞在生物支架上的生长行为受到支架表面形貌、润湿性、孔径及孔隙率等多种因素影响。目的:观察许旺细胞在不同孔径丝素蛋白支架上的生长情况。方法:制备大孔径50～60μm、小孔径10～20μm两种多孔丝素材料。选用许旺细胞永生化细胞R3[33-10ras3]为种子细胞,当细胞在培养瓶底形成致密单层时即可消化细胞并进行接种实验,将许旺细胞悬液种于不同形貌的多孔丝素材料表面。复合培养1周后,扫描电镜观察许旺细胞的生长形态及增殖等情况。结果与结论:不同孔径丝素材料的表面可见许旺细胞生长情况不一。在10～20μm孔径材料支架上,细胞浓度较低,细胞表现为特异的双极性形态,细胞与细胞之间或平行排列,或首尾相连成细胞链;细胞与细胞之间或平行排列,或首尾相连成细胞链;在50～60μm孔径丝素材料支架上,细胞浓度较高,细胞多为球形,单个分散在多孔支架表面,或呈现成团成串葡萄样聚集在孔的底部,未延展成双极性形态,只有极少量生长在孔与孔之间嵴上的细胞呈双极样。说明多孔丝素蛋白支架的孔径对许旺细胞的黏附、生长有一定的影响,许旺细胞更适合生长在孔径略大于胞体直径的支架材料上。     

许旺细胞在不同孔径丝素蛋白支架上的生长

背景：细胞在生物支架上的生长行为受到支架表面形貌、润湿性、孔径及孔隙率等多种因素影响。目的：观察许旺细胞在不同孔径丝素蛋白支架上的生长情况。方法：制备大孔径50～60μm、小孔径10～20μm两种多孔丝素材料。选用许旺细胞永生化细胞R3[33-10ras3]为种子细胞,当细胞在培养瓶底形成致密单层时即可消化细胞并进行接种实验,将许旺细胞悬液种于不同形貌的多孔丝素材料表面。复合培养1周后,扫描电镜观察许旺细胞的生长形态及增殖等情况。结果与结论：不同孔径丝素材料的表面可见许旺细胞生长情况不一。在10～20μm孔径材料支架上,细胞浓度较低,细胞表现为特异的双极性形态,细胞与细胞之间或平行排列,或首尾相连成细胞链;细胞与细胞之间或平行排列,或首尾相连成细胞链;在50～60μm孔径丝素材料支架上,细胞浓度较高,细胞多为球形,单个分散在多孔支架表面,或呈现成团成串葡萄样聚集在孔的底部,未延展成双极性形态,只有极少量生长在孔与孔之间嵴上的细胞呈双极样。说明多孔丝素蛋白支架的孔径对许旺细胞的黏附、生长有一定的影响,许旺细胞更适合生长在孔径略大于胞体直径的支架材料上。     

Pd(ii) and Pt(ii) complexes of tridentate ligands with selective toxicity against Cryptococcus neoformans and Candida albicans

Novel Pd(ii) and Pt(ii) complexes of the tridentate 2,6-bis(1-ethyl-benzimidazol-2′-yl)pyridine (L^BZ), and 4′-(2-pyridyl)-2,2′:6′,2′′-terpyridine (L^PY) ligands were synthesized, characterized using a variety of analytical and spectroscopic tools, and screened for their potential antimicrobial properties against some bacterial and fungal strains as well as cytotoxicity against healthy human embryonic kidney (HEK293) cells. The electronic structures of the complexes were investigated by time-dependent density functional theory calculations. The free ligand L^PY and benzimidazole complexes exhibited selective toxicity against Cryptococcus neoformans and Candida albicans, while displaying no cytotoxicity against HEK293. In the case of Cryptococcus neoformans, the antifungal activities of the benzimidazole-based complexes (MIC = 1.58–2.62 μM) are higher than those of the reference drug fluconazole (26.1 μM).

The terpyridine ligand and the Pd(ii) and Pt(ii) benzimidazole complexes exhibited selective toxicity against Cryptococcus neoformans and Candida albicans, while displaying no cytotoxicity against healthy HEK293 cells.     

Selective preconcentration separation of Hg(ii) and Cd(ii) from water,fish muscles,and cucumber samples using recycled aluminum adsorbents

Modified aluminum scrap waste was used in the selective extraction of Hg(ii), and Cd(ii) ions. The aluminum scraps were modified with dibenzoylmethane, or isatoic anhydride, or 5-(2-chloroacetamide)-2-hydroxybenzoic acid. The modified aluminum sorbents were characterized by FT-IR, SEM, XRD, XPS, TGA, and elemental analysis. Modes of chelation between adsorbents and target metal ions were deduced via DFT. The highest adsorption capacity was observed for benzo-amino aluminum (BAA) toward Hg(ii), which reached 234.56 mg g⁻¹, while other modified sorbents ranged from 135.28 mg g⁻¹ to 229.3 mg g⁻¹. Under the optimized conditions, the BAA adsorbent showed a lower limit of detection (1.1 mg L⁻¹) and limit of quantification (3.66 mg L⁻¹) for mercury ions than other sorbents. The prepared aluminum adsorbents also exhibited significant selectivities for Hg(ii) and Cd(ii) ions in the presence of competing metal ions.

Modified aluminum scrap waste was used in the selective extraction of Hg(ii), and Cd(ii) ions.     

Synthesis and characterization of a surface-grafted Pb(ii)-imprinted polymer based on activated carbon for selective separation and pre-concentration of Pb(ii) ions from environmental water samples

Even the lowest concentration level of lead (Pb) in the human body is dangerous to health due to its bioaccumulation and high toxicity. Therefore, it is very important to develop selective and fast adsorption methods for the removal of Pb(ii) from various samples. In this paper, a new Pb(ii) ion-imprinted polymer (Pb(ii)-IIP) was prepared with surface imprinting technology by using lead nitrate as a template, for the solid-phase extraction of trace Pb(ii) ions in environmental water samples. The imprinted polymer was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy and N₂ adsorption–desorption isotherms. The separation/pre-concentration conditions for Pb(ii) were investigated, including the effects of pH, shaking time, sample flow rate, elution conditions and interfering ions. Compared with non-imprinted particles, the ion-imprinted polymer had a higher selectivity and adsorption capacity for Pb(ii). The pseudo-second-order kinetics model and Langmuir isotherm model fitted well with the adsorption data. The relative selectivity factor values (α_r) of Pb(ii)/Zn(ii), Pb(ii)/Ni(ii), Pb(ii)/Co(ii) and Pb(ii)/Cu(ii) were 168.20, 192.71, 126.13 and 229.39, respectively, which were all much greater than 1. The prepared Pb(ii)-imprinted polymer was shown to be promising for the separation/pre-concentration of trace Pb(ii) from natural water samples. The adsorption and desorption mechanisms were also proposed.

Even the lowest concentration level of lead (Pb) in the human body is dangerous to health due to its bioaccumulation and high toxicity.     

Hexanuclear Cu3O–3Cu triazole-based units as novel core motifs for high nuclearity copper(ii) frameworks

The asymmetric 3,5-disubstituted 1,2,4-triazole ligand H₂V (5-amino-3-picolinamido-1,2,4-triazole) by reaction with an excess of Cu(ii) perchlorate (Cu : H₂V being 12 : 1) has produced a novel hexanuclear {Cu₆(μ₃-O/H)(HV/V)₃} fragment, with one triangular Cu₃(μ₃-O/H) group connected to three peripheral single Cu(ii) ions through a cis–cis–trans bridging mode of the ligand, which is the building block of the three structures described here: one hexanuclear, [Cu₆(μ₃-O)(HV)₃(ClO₄)₇(H₂O)₉]·8H₂O (1), one dodecanuclear, [Cu₁₂(μ₃-O)₂(V)₆(ClO₄)₅(H₂O)₁₈](ClO₄)₃·6H₂O (2), and one tetradecanuclear 1D-polymer, {[Cu₁₄(μ₃-OH)₂(V)₆(HV)(ClO₄)₁₁(H₂O)₂₀](ClO₄)₂·14H₂O}_n (3), the last two containing hexanuclear subunits linked by perchlorato bridges. The Cu–Cu av. intra-triangle distance is 3.352(2) Å and the Cu(central)–Cu(bridged external) av. distance is 5.338(3) Å. The magnetic properties of the hexanuclear “Cu₃O–3Cu” cluster have been studied, resulting as best fit parameters: g = 2.18(1), J(intra-triangle) = −247.0(1) cm⁻¹ and j(central Cu^II – external Cu^II) = −5.15(2) cm⁻¹.

The novel hexanuclear {Cu₆(μ₃-O/H)(HV/V)₃} fragment is the building block of the hexanuclear, the dodecanuclear and the tetradecanuclear-1D-polymeric structures described here.     

不同孔径微孔滤膜对肿瘤细胞滤过的影响

目的探讨不同孔径微孔滤膜对不同直径大小的肿瘤细胞的滤过作用及其对过滤后细胞活性的影响。方法选择不同孔径(1、3、5、8、10μm)的聚碳酸酯微孔滤膜分别过滤浓度相同但细胞直径不同的Jurkat、K562和A549细胞,测定细胞通过滤膜的滤过率;光学显微镜测量3种细胞(包括甲醛固定后的K562)的直径及其经不同孔径的滤膜过滤后的细胞直径;台盼蓝染色法检测经滤膜过滤后的K562细胞活性,对细胞进行再培养,并用生长曲线分析其细胞增殖能力。结果 Jurkat、K562和A549细胞均不能通过1μm孔径的滤膜,通过3、5、8、10μm孔径滤膜的滤过率均依次升高。经3μm孔径滤膜滤过的K562细胞存活率为92.0%,且滤过后的细胞再培养后的细胞增殖能力仍较强。经甲醛固定的K562细胞的滤过率明显降低,且细胞平均直径无明显变化。结论活细胞能穿过孔径小于其直径的滤膜;穿过滤膜的细胞仍保持活性增殖,但甲醛固定可明显减少细胞通过滤膜。     

Impact of drying/wetting conditions on the binding characteristics of Cu(ii) and Cd(ii) with sediment dissolved organic matter

The biogeochemical processing of dissolved organic matter (DOM) in bottomland sediment under drying/wetting conditions regulates the environmental behavior of heavy metals. Although moisture is a critical factor, the structural characteristics of DOM and its reactivity with heavy metals under drying/wetting conditions are not well known. Herein, the response of DOM to drying/wetting conditions and its influence on the binding of Cu(ii) and Cd(ii) onto DOM were clarified via various multi-spectroscopic techniques. Ultraviolet-visible spectra (UV-Vis) showed that higher aromatic, hydrophobic, and molecular weight fractions were observed in sediment DOM under drying conditions than those under wetting conditions. The binding abilities for Cd(ii) with DOM under drying/wetting conditions are lower than those for Cu(ii). The stability constants between Cu(ii) and DOM were found to decrease under drying/wetting conditions; however, the binding capacities for Cu(ii) increased, especially under wetting conditions. Two-dimensional correlation spectroscopy based on Fourier-transform infrared (FTIR) and synchronous fluorescence spectra (SFS) showed that Cu(ii) and Cd(ii) have different binding sequences and binding sites and that Cu(ii) has more binding sites under drying and wetting conditions; however, Cd(ii) shows the opposite behavior. These results clearly demonstrate that the binding of sediment DOM with Cu(ii) is more prevalent and stable compared with Cd(ii) under drying and wetting conditions. Because of its relatively low binding capacity and binding stability, Cd(ii) can exhibit a high environmental hazard for migration and transformation with DOM due to water flow under wetting conditions. This study helps reveal the impact of drying/wetting conditions on the environmental behavior of heavy metals in bottomland wetlands.

The biogeochemical processing of dissolved organic matter (DOM) in bottomland sediment under drying/wetting conditions regulates the environmental behavior of heavy metals.     

Efficient removal of Cu(ii) from aqueous systems using enhanced quantum yield nitrogen-doped carbon nanodots

The valorization of cellulose-based waste is of prime significance to green chemistry. However, the full exploitation of these lignocellulosic compounds to produce highly luminescent nanoparticles under mild conditions has not yet been achieved. In this context, we convert low-quality waste into value-added nanomaterials for the removal of Cu(ii) from wastewater. Carboxymethylcellulose (CMC), which was derived from empty fruit bunches, was selected for its high polymerization index to produce luminescent nitrogen-doped carbon dots (N-CDs) with the assistance of polyethylene glycol (PEG) as a dopant. The optimum N-CD sample with the highest quantum yield (QY) was characterized using various analytical techniques and the results show that the N-CDs have great crystallinity, are enriched with active sites and exhibit a long-shelf life with an enhanced QY of up to 27%. The influence of Cu²⁺ concentration, adsorbent (N-CDs) dosage, pH and contact time were investigated for the optimal adsorption of Cu²⁺. The experiments showed the rapid adsorption of Cu²⁺ within 30 min with a removal efficiency of over 83% under optimal conditions. The equilibrium isotherm investigation revealed that the fitness of the Langmuir isotherm model and kinetic data could be well explained by the pseudo-second order model. Desorption experiments proved that N-CDs can be regenerated successfully over five adsorption–desorption cycles owing to the ability of ascorbic acid (AA) to reduce the adsorbed nanocomplex into Cu⁺. The rapid adsorption property using low-cost materials identifies N-CDs as a superior candidate for water remedy.

Low value waste resources have been converted into value-added luminescence carbon dots for copper adsorption from contaminated water.     

Cu(ii) Schiff base complex intercalated into layered double hydroxide for selective oxidation of ethylbenzene under solvent-free conditions

A new heterogeneous catalyst was prepared by intercalation of NNOO donor Cu(ii) Schiff base complex derived from 2-hydroxy-1-naphthaldehyde and 4-amino benzoic acid into Zn–Al layered double hydroxide {LDH-[NAPABA–Cu(ii)]}. Synthesized catalyst was characterized by Inductively coupled plasma atomic emission spectroscopy, energy dispersive X-ray analysis, scanning electron microscopy, X-ray diffraction, Transmission electron microscopy, BET surface area, Fourier transform infrared spectroscopy, thermo-gravimetric analysis, electron paramagnetic resonance spectroscopy and diffuse reflectance UV-visible spectroscopy. The catalytic performance of LDH-[NAPABA–Cu(ii)] was studied for the liquid phase solvent-free oxidation of ethylbenzene at 393 K, using tert-butylhydroperoxide as an oxidant. In oxidation reaction ethylbenzene was oxidized to acetophenone, benzaldehyde and benzoic acid. The major product was acetophenone. A maximum, 80.54% conversion of ethylbenzene was observed after 7 hours. The catalyst was recycled seven times without significant loss of catalytic activity.

A heterogeneous catalytic system, LDH-[NAPABA–Cu(ii)]/TBHP gave maximum 80.54% conversion and 99.60% selectivity for acetophenone in oxidation of ethylbenzene and catalyst can be reused for seven cycles.     

Highly-efficient removal of Pb(ii), Cu(ii) and Cd(ii) from water by novel lithium,sodium and potassium titanate reusable microrods

In this work, we report on the efficient removal of heavy metal ions with nanostructured lithium, sodium and potassium titanates from simulated wastewater. The titanates were obtained via a fast, easy and cost effective process based on extraction of sulfate ions from the crystals of titanyl sulfate and their replacement with hydroxyl groups of NaOH, LiOH and KOH solutions leaving the Ti–O framework intact. The as-prepared titanates were carefully examined by scanning and transmission electron microscopy. Furthermore, the effect of contact time, pH, annealing temperature, together with adsorption in real conditions including competitive adsorption and reusability were studied. It was found that the maximum adsorption capacity, as calculated from the Langmuir adsorption model, is up to 3.8 mmol Pb(ii) per g, 3.6 mmol Cu(ii) per g and 2.3 mmol Cd(ii) per g. Based on the characterization results, a possible mechanism for heavy metal removal was proposed. This work provides a very efficient, fast and convenient approach for exploring promising materials for water treatment.

This work provides a very efficient, fast and convenient approach for exploring promising materials for water treatment.     

Simultaneous removal of tetracycline and Cu(ii) by adsorption and coadsorption using oxidized activated carbon

Co-contamination of antibiotics and heavy metals prevails in the environment. To overcome the obstacle of low metal uptake on activated carbon and to achieve simultaneous removal of tetracycline (TC) and Cu(ii) from water, coconut shell based granular activated carbon (GAC) treated with nitric acid was utilized. GAC property characterization showed that oxidation treatment distinctly decreased the surface area of GAC and significantly increased the content of oxygen containing functional groups. The oxidized GAC exhibited greater adsorption capacity for individual TC and Cu(ii). Kinetics studies demonstrated that although the overall removal rate of coexisting TC and Cu(ii) decreased, the ultimate removal efficiency was further enhanced in the binary system. The adsorption isotherms were well described by Langmuir and Freundlich models. Moreover, the maximum adsorption capacities of coexisting TC and Cu(ii) with oxidized GAC kept increasing within a pH range of 3.0–6.0, indicating an electrostatic repulsion mechanism as well as a competition for adsorption sites. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis revealed that the enhanced removal of TC and Cu(ii) was very likely as a result of coadsorption by forming TC–Cu(ii) complexes bridging between the adsorbate and the adsorbent.

The enhanced coadsorption of TC and Cu(ii) was likely due to the formation of a TC–Cu(ii) complex bridging.     

Fast removal of Co(ii) from aqueous solution using porous carboxymethyl chitosan beads and its adsorption mechanism

Porous carboxymethyl chitosan (PCMC) beads were synthesized via ionic coacervation/chemical crosslinking, using polyethylene glycol (PEG) as a porogen and calcium chloride and glutaraldehyde as physical and chemical cross-linkers. The as-synthesized PCMC beads were characterized using SEM, EDS, BET, TGA, FTIR and XPS analysis and then tested for the removal of Co(ii) from aqueous solution. The effects of the initial pH, Co(ii) concentration and temperature were investigated. It was found that the adsorption equilibrium is reached within 6 h and the maximum adsorption capacity is 46.25 mg g⁻¹. In addition, the kinetics and equilibrium data are well described by pseudo-second-order kinetics and the Langmuir isotherm model. Moreover, the desorption and re-adsorption performance was also studied, and the results revealed that the prepared new adsorbent still showed good adsorption performance after five cycles of regeneration. Finally, the adsorption mechanism, including chemical and physical adsorption, was proposed on the basis of the microstructure analysis, adsorption kinetics and isotherm results, and chemical adsorption was found to be the main adsorption mechanism during the process of the removal of Co(ii).

The as-prepared adsorbent exhibits excellent adsorption capacity and fast kinetics for Co(ii).     

Highly efficient removal of Cu(ii) by novel dendritic polyamine–pyridine-grafted chitosan beads from complicated salty and acidic wastewaters

In this study, dendritic polyamine chitosan beads with and without 2-aminomethyl pyridine were facilely prepared and characterized. Compared to CN (without the pyridine function), more adsorption active sites, larger pores, higher nitrogen content, higher specific surface area, and higher strength could be obtained for CNP (with the pyridine function). CNP microspheres afforded a larger adsorption capacity than those obtained by CN for different pH values; further, the uptake amounts of Cu(ii) were 0.84 and 1.12 mmol g⁻¹ for CN and CNP beads, respectively, at pH 5. The CNP microspheres could scavenge Cu(ii) from highly acidic and salty solutions: the maximum simulated uptake amount of 1.93 mmol g⁻¹ at pH 5 could be achieved. Due to the strong bonding ability and weakly basic property of pyridine groups, the adsorption capacity of Cu(ii) at pH 1 was 0.75 mmol g⁻¹ in highly salty solutions, which was comparative to those obtained from the commercial pyridine chelating resin M4195 (Q_Cu(II) = 0.78 mmol g⁻¹ at pH 1). In addition, a distinct salt-promotion effect could be observed for CNP beads at both pH 5 and 1. Therefore, the prepared adsorbent CNP beads can have promising potential applications in the selective capturing of heavy metals in complex solutions with higher concentrations of H⁺ and inorganic salts, such as wastewaters from electroplating liquid and battery industries.

Dendritic polyamine chitosan (CNP) beads containing 2-aminomethyl pyridine were facilely prepared for the efficient removal of Cu(ii) ions from highly acidic and salty solutions.     

Adsorption of Cu(ii), Zn(ii), and Pb(ii) from aqueous single and binary metal solutions by regenerated cellulose and sodium alginate chemically modified with polyethyleneimine

In this paper, crosslinked cellulose/sodium alginate (SA) was modified with polyethyleneimine (PEI) as an adsorbent (PEI-RCSA) for comparative and competitive adsorption of Cu(ii), Zn(ii), and Pb(ii) in single and binary aqueous solutions. FTIR, SEM, TGA and specific surface area analysis were used to characterize the structural characteristics of PEI-RCSA. The effects of initial pH of solutions, contact time and initial concentration of heavy metal ions on the adsorption capacity of PEI-RCSA were investigated. The experimental results revealed that the removal of metal ions on the PEI-RCSA was a pH-dependent process with the maximum adsorption capacity at the initial solution pH of 5–6. The adsorption kinetics were followed by a pseudo-second-order kinetics model, and the diffusion properties played a significant role in the control of the adsorption kinetics. Meanwhile, adsorption isotherms were successfully described by the Langmuir model in a single aqueous solution system. The maximum adsorption capacities of PEI-RCSA for Cu(ii), Zn(ii), and Pb(ii) in a single system were 177.1, 110.2 and 234.2 mg g⁻¹, respectively. The binary-component system was better described with the Langmuir competitive isotherm model. The removal efficiencies didn''t change significantly when three adsorption–desorption experimental cycles were conducted. All the above results indicated that PEI-RCSA has promising applications in the treatment of toxic metal pollution.

Crosslinked cellulose/sodium alginate was modified with polyethyleneimine as an adsorbent (PEI-RCSA) for comparative and competitive adsorption of metal ions.     

Extraction and preconcentration of Ni(ii), Pb(ii), and Cd(ii) ions using a nanocomposite of the type Fe3O4@SiO2@polypyrrole-polyaniline

In this study, the application of Fe₃O₄@SiO₂@polypyrrole-polyaniline magnetic nanocomposite was studied for Ni(ii), Cd(ii), and Pb(ii) ions preconcentration extraction. In this regard, the silica layer prevents the Fe₃O₄ nanoparticles (NPs) from aggregating over a broad pH range value and simultaneously improves chemical stability and hydrophilicity. By using a Box–Behnken design, the effect of various parameters affecting the preconcentration was studied. FAAS was employed to quantify the eluted analytes. The detection limits are 0.09, 1.1, and 0.3 ng mL⁻¹ for Ni(ii), Cd(ii) and Pb(ii), ions, respectively. The relative standard deviations (RSDs%) were calculated for determining the method''s precision, lower than 7.5%. The capacities of sorption are 75, 84, and 98 mg g⁻¹, respectively. With the usage of a certified reference material, the developed method was validated. After that, the validated method was employed to rapidly extract trace target ions from food samples and gave satisfactory results.

In this study, the application of Fe₃O₄@SiO₂@polypyrrole-polyaniline magnetic nanocomposite was studied for Ni(ii), Cd(ii), and Pb(ii) ions preconcentration extraction.     

Synthesis,structural characterization and Cu(ii) adsorption behavior of manganite (γ-MnOOH) nanorods

New alternatives for the removal of transition metal ions that present an environmental risk are required. The chemical adsorption of these ions on surfaces with chemisorbent properties represents a promising area of research. In this work, manganite (γ-MnOOH) nanorods were synthesized, with a surface area of 20.22 m² g⁻¹, pore size of 32.18 nm and pore volume of 0.1627 cm³ g⁻¹. After chemical and structural characterization of the manganite sample, it was evaluated as an adsorbent of Cu(ii) from aqueous solution. The equilibrium adsorption data were well fitted by the Langmuir isotherm, and the results indicated that the maximum adsorption capacity of Cu(ii) was 11.926 mg g⁻¹. Cu(ii) ion adsorption on the manganite surface is a spontaneous and exothermic process (ΔG°< 0 and ΔH°< 0). The negative value of ΔS° suggests the stability of the adsorption process without structural change at the manganite–aqueous solution interface. A scheme for chemisorption of Cu(ii) ions on the hydroxylated surface of manganite is proposed.

Manganite (γ-MnOOH) nanorods were synthesized and Cu(ii) adsorption on their hydroxylated surface was a spontaneous process (ΔG° < 0).