scholarly journals Involute the reactivity of persulfate with zero-valent iron for enhanced removal of arsenic (V) in aspect involvement of Fe2+ or Fe3+

2019 ◽  
Vol 80 (6) ◽  
pp. 1031-1041
Author(s):  
Yue Wang ◽  
Tianying Chang ◽  
Zhengchao Zhang ◽  
Kaijie Pei ◽  
Jie Fu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sewage Treatment ◽  
Industrial Effluents ◽  
Ferrous Ions ◽  
Metals Removal ◽  
Wide Range ◽  
Pseudo Second Order ◽  
Timely Fashion ◽  
Co Precipitation ◽  
Removal Of Arsenic

Abstract Being a fundamental issue regarding sewage treatment, heavy metals removal from industrial effluents has been subject to intense scrutiny in both the academic and practical worlds. The removal of pentavalent arsenic (As(V)), one of the most poisonous pollutants, was investigated using a sodium persulfate and iron powder system activated by ferrous ions (Fe2+-ZVI-PS). As(V) could be effectively removed by an Fe2+-ZVI-PS system in a timely fashion (minute scale) with high removal rates (more than 90.0%) over a wide range of pH (1–9) and concentration (20–100 mg/L). The removal of As(V) by the Fe2+-ZVI-PS system integrated favorably with the pseudo-second-order reaction kinetics. Researches on X-ray photoelectron spectroscopy (XPS) demonstrated that the Fe2+-ZVI-PS system enables the removal of As(V) through the process of co-precipitation and adsorption. Our findings thus emphasized that the Fe2+-ZVI-PS system should be an effective trigger to purifying arsenic from the environment. Our results indicated that the Fe2+-ZVI-PS system could be an effective candidate for remediation of arsenic in the environment.

scholarly journals Synthesis of Nanoscale Zerovalent Iron (nZVI) Supported on Biochar for Chromium Remediation from Aqueous Solution and Soil

2019 ◽  
Vol 16 (22) ◽  
pp. 4430 ◽  
Author(s):  
Haixia Wang ◽  
Mingliang Zhang ◽  
Hongyi Li
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Zero Valent Iron ◽  
Zerovalent Iron ◽  
X Ray ◽  
Nanoscale Zerovalent Iron ◽  
Before And After ◽  
Pseudo Second Order ◽  
Xrd Patterns ◽  
Co Precipitation

Maize straw biochar-supported nanoscale zero-valent iron composite (MSB-nZVI) was prepared for efficient chromium (Cr) removal through alleviating the aggregation of zero-valent iron particles. The removal mechanism of MSB-nZVI was investigated by scanning electron microscopy with energy dispersive X-ray (SEM-EDX), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). Cr(VI) removal from aqueous solution by MSB-nZVI was greatly affected by pH and initial concentration. The removal efficiency of Cr(VI) decreased with increasing pH, and the removal kinetics followed the pseudo-second-order model. XRD patterns of MSB-nZVI before and after reaction showed that reduction and precipitation/co-precipitation (FeCr2O4, Fe3O4, Fe2O3) occurred with the conversion of Cr(VI) to Cr(III) and Fe(0) to Fe(II)/Fe(III). The produced precipitation/co-precipitation could be deposited on the MSB surface rather than being only coated on the surface of nZVI particles, which can alleviate passivation of nZVI. For remediation of Cr(VI)-contaminated saline–alkali soil (pH 8.6–9.0, Cr 341 mg/kg), the released amount of Cr(VI) was 70.7 mg/kg, while it sharply decreased to 0.6–1.7 mg/kg at pH 4.0–8.0, indicating that the saline–alkali environment inhibited the remediation efficiency. These results show that MSB-nZVI can be used as an effective material for Cr(VI) removal from aqueous solution and contaminated soil.

scholarly journals Removal of Cesium and Strontium From Radioactive Wastewater by Prussian Blue Nanorods

2022 ◽  
Author(s):  
Chuqing Yao ◽  
Yaodong Dai ◽  
Shuquan Chang ◽  
Haiqian Zhang
Keyword(s):  
Prussian Blue ◽  
Photoelectron Spectroscopy ◽  
Adsorption Process ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radioactive Wastewater ◽  
Pseudo Second Order ◽  
Co Precipitation ◽  
Solvothermal Methods

Abstract In this work, novel Prussian blue tetragonal nanorods were prepared by template-free solvothermal methods for removal of radionuclide Cs and Sr. It was worth that Prussian blue nanorods exhibited the better adsorption performance than co-precipitation PB or Prussian blue analogue composites. Thermodynamic analysis implied that adsorption process was spontaneous and endothermic which was described well with Langmuir isotherm and pseudo-second-order equation, the maximum adsorption capacity of PB nanorod was estimated to be 194.26 mg g-1 and 256.62 mg g-1 for Cs+ and Sr2+. The adsorption mechanism of Cs+ and Sr2+ was studied by X-ray photoelectron spectroscopy, X-ray diffraction and 57Fe Mössbaure spectroscopy, the results revealed that Cs+ entered in PB crystal to generate a new phase, the most of Sr2+ was trapped in internal crystal and the other exchanged Fe2+. Furthermore, the effect of co-existing ions and pH for PB adsorption process were also investigated. The results suggest that PB nanorods were outstanding candidate for removal of Cs+ and Sr2+ from radioactive wastewater.

Synthesis of magnetic biochar derived from cotton stalks for the removal of Cr(VI) from aqueous solution

2019 ◽  
Vol 79 (11) ◽  
pp. 2106-2115 ◽  
Author(s):  
Fengfeng Ma ◽  
Baowei Zhao ◽  
Jingru Diao
Keyword(s):  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Cotton Stalk ◽  
Magnetic Biochar ◽  
X Ray ◽  
Cotton Stalks ◽  
Pseudo Second Order ◽  
Co Precipitation

Abstract A magnetic cotton stalk biochar (MCSBC) was synthesized through chemical co-precipitation, based on cotton stalk biochar (CSBC). The MCSBC and CSBC were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and vibrating sample magnetometry. The characterization analyses showed that the magnetization process endowed the CSBC with excellent magnetic properties with a superparamagnetic magnetization of 27.59 emu/g. Batch adsorption experiment results indicated that the Cr(VI) maximum adsorption capacity of MCSBC was 20.05 mg/g, which was higher than that of CSBC (18.77 mg/g). The adsorption kinetic data were well fitted by the pseudo-second-order model and the adsorption isotherms were well represented by the Sips isotherm model. The thermodynamic studies indicated that the adsorption process was spontaneous and endothermic, and the entropy increased. The potential adsorption mechanism was the electrostatic adsorption of anionic Cr(VI) to the positively charged MCSBC surface, the reduction of Cr(VI) into Cr(III) and the complexation of Cr(III) by oxygen-containing functional groups of MCSBC. The regeneration studies showed that MCSBC kept 80% of its initial Cr(VI) adsorption capacity in the cycle. All the findings suggest that this novel magnetic biochar could be used in the field of Cr(VI)-containing wastewater treatment.

scholarly journals Toxic heavy metals removal using a hydroxyapatite and hydroxyethyl cellulose modified with a new Gum Arabic

2021 ◽  
Vol 6 (1) ◽  
pp. 41-64
Author(s):  
A Errich ◽  
K Azzaoui ◽  
E Mejdoubi ◽  
B Hammouti ◽  
N Abidi ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Gum Arabic ◽  
Hydroxyethyl Cellulose ◽  
Standard Entropy ◽  
Toxic Heavy Metals ◽  
Solution Ph ◽  
Force Microscopy ◽  
Metals Removal ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order

The objective of this work was to develop a process that allows the synthesis of an apatitic material of controlled composition and morphology, which could be used for medical and environmental applications. The adsorbent was synthesized, and characterized using scanning electron microscopy, nuclear magnetic resonance, Thermal analysis and other techniques, Atomic Force Microscopy, X-ray photoelectron spectroscopy and Total organic carbon. Different experimental parameters such as the effect of the amount of adsorbent, solution pH and temperatures and contact times were studied. Pseudo-order kinetics models were studied, and our data followed a pseudo second order. Experimental data were analyzed for both Langmuir and Freundlich models and the data fitted well with the Langmuir isotherm model. To understand the mechanism of adsorption, thermodynamic parameters like standard enthalpy, standard Gibbs free energy, and standard entropy were studied. The study indicated that the process is spontaneous, exothermic in nature and follow physisorption mechanisms. The novelty of this study showed surface of composite based of hydroxyapatite has the ability to highlight the surface designed for efficient removal of Cu2+ and Zn2+ ions, from aqueous solutions more than other studies.

scholarly journals Surface Properties of Halloysite-Carbon Nanocomposites and Their Application for Adsorption of Paracetamol

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5647
Author(s):  
Beata Szczepanik ◽  
Dariusz Banaś ◽  
Aldona Kubala-Kukuś ◽  
Karol Szary ◽  
Piotr Słomkiewicz ◽  
...  
Keyword(s):  
Surface Properties ◽  
Photoelectron Spectroscopy ◽  
Adsorption Model ◽  
Xps Spectra ◽  
Carbon Nanocomposites ◽  
Wide Range ◽  
Intra Particle Diffusion ◽  
Pseudo Second Order ◽  
Energy Survey ◽  
Photoelectron Peak

Analysis of surface properties of halloysite-carbon nanocomposites and non-modified halloysite was carried out with surface sensitive X-ray photoelectron spectroscopy (XPS) and inverse gas chromatography (IGC). The XPS spectra were measured in a wide range of the electron binding energy (survey spectra) and in the region of C 1s photoelectron peak (narrow scans). The IGC results show the changes of halloysite surface from basic for pure halloysite to acidic for carbon-halloysite nanocomposites. Halloysite-carbon nanocomposites were used as adsorbents of paracetamol from an aqueous solution. The adsorption mechanism was found to follow the pseudo-second-order and intra-particle diffusion models. The Langmuir multi-center adsorption model described well the obtained experimental data. The presence of carbon increased significantly the adsorption ability of halloysite-carbon nanocomposites for paracetamol in comparison to the non-modified halloysite.

scholarly journals Interactions of Cd2+, Co2+ and MoO42− Ions with Crushed Concrete Fines

2021 ◽  
Vol 5 (2) ◽  
pp. 42
Author(s):  
Victoria K. Elmes ◽  
Nichola J. Coleman
Keyword(s):  
Contaminated Soils ◽  
Aqueous Media ◽  
Fine Fraction ◽  
Freundlich Isotherm ◽  
Crushed Concrete ◽  
Pseudo Second Order ◽  
Zero Order Reaction ◽  
Co Precipitation ◽  
Material Accounting ◽  
Effective Sorbent

Construction and demolition activities generate approximately two thirds of the world’s waste, with concrete-based demolition material accounting for the largest proportion. Primary aggregates are recovered and reused, although the cement-rich fine fraction is underutilised. In this study, single metal batch sorption experiments confirmed that crushed concrete fines (CCF) are an effective sorbent for the maximum exclusion of 45.2 mg g−1 Cd2+, 38.4 mg g−1 Co2+ and 56.0 mg g−1 MoO42− ions from aqueous media. The principal mechanisms of sorption were determined, by scanning electron microscopy of the metal-laden CCF, to be co-precipitation with Ca2+ ions released from the cement to form solubility limiting phases. The removal of Co2+ and MoO42− ions followed a zero-order reaction and that of Cd2+ was best described by a pseudo-second-order model. The Langmuir model provided the most appropriate description of the steady state immobilisation of Cd2+ and Co2+, whereas the removal of MoO42− conformed to the Freundlich isotherm. Long equilibration times (>120 h), loose floc formation and high pH are likely to limit the use of CCF in many conventional wastewater treatment applications; although, these properties could be usefully exploited in reactive barriers for the management of contaminated soils, sediments and groundwater.

scholarly journals Synthesis of Ce1−xPdxO2−δ Solid Solution in Molten Nitrate

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 640
Author(s):  
Hideaki Sasaki ◽  
Keisuke Sakamoto ◽  
Masami Mori ◽  
Tatsuaki Sakamoto
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Solid Solutions ◽  
Photoelectron Spectroscopy ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Ionic States

CeO2-based solid solutions in which Pd partially substitutes for Ce attract considerable attention, owing to their high catalytic performances. In this study, the solid solution (Ce1−xPdxO2−δ) with a high Pd content (x ~ 0.2) was synthesized through co-precipitation under oxidative conditions using molten nitrate, and its structure and thermal decomposition were examined. The characteristics of the solid solution, such as the change in a lattice constant, inhibition of sintering, and ionic states, were examined using X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM−EDS), transmission electron microscopy (TEM)−EDS, and X-ray photoelectron spectroscopy (XPS). The synthesis method proposed in this study appears suitable for the easy preparation of CeO2 solid solutions with a high Pd content.

scholarly journals Reactivity and Chemical Sintering of Carey Lea Silver Nanoparticles

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1525
Author(s):  
Sergey Vorobyev ◽  
Elena Vishnyakova ◽  
Maxim Likhatski ◽  
Alexander Romanchenko ◽  
Ivan Nemtsev ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Silver Nanoparticles ◽  
Flexible Electronics ◽  
Photoelectron Spectroscopy ◽  
Colloidal Solutions ◽  
Ag Nps ◽  
Wide Range ◽  
Carboxylic Groups ◽  
The Media ◽  
Sulfide Ions

Carey Lea silver hydrosol is a rare example of very concentrated colloidal solutions produced with citrate as only protective ligands, and prospective for a wide range of applications, whose properties have been insufficiently studied up to now. Herein, the reactivity of the immobilized silver nanoparticles toward oxidation, sulfidation, and sintering upon their interaction with hydrogen peroxide, sulfide ions, and chlorocomplexes of Au(III), Pd(II), and Pt(IV) was investigated using SEM and X-ray photoelectron spectroscopy (XPS). The reactions decreased the number of carboxylic groups of the citrate-derived capping and promoted coalescence of 7 nm Ag NPs into about 40 nm ones, excluding the interaction with hydrogen peroxide. The increased nanoparticles form loose submicrometer aggregates in the case of sulfide treatment, raspberry-like micrometer porous particles in the media containing Pd(II) chloride, and densely sintered particles in the reaction with inert H2PtCl6 complexes, probably via the formation of surface Ag-Pt alloys. The exposure of Ag NPs to HAuCl4 solution produced compact Ag films along with nanocrystals of Au metal and minor Ag and AgCl. The results are promising for chemical ambient temperature sintering and rendering silver-based nanomaterials, for example, for flexible electronics, catalysis, and other applications.

scholarly journals A Highly Sensitive Room Temperature CO2 Gas Sensor Based on SnO2-rGO Hybrid Composite

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 522
Author(s):  
Zhi Yan Lee ◽  
Huzein Fahmi bin Hawari ◽  
Gunawan Witjaksono bin Djaswadi ◽  
Kamarulzaman Kamarudin
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Gas Sensor ◽  
Photoelectron Spectroscopy ◽  
Hybrid Composite ◽  
Room Temperature ◽  
Co2 Gas ◽  
X Ray ◽  
Wide Range ◽  
Co2 Gas Sensor

A tin oxide (SnO2) and reduced graphene oxide (rGO) hybrid composite gas sensor for high-performance carbon dioxide (CO2) gas detection at room temperature was studied. Since it can be used independently from a heater, it emerges as a promising candidate for reducing the complexity of device circuitry, packaging size, and fabrication cost; furthermore, it favors integration into portable devices with a low energy density battery. In this study, SnO2-rGO was prepared via an in-situ chemical reduction route. Dedicated material characterization techniques including field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) were conducted. The gas sensor based on the synthesized hybrid composite was successfully tested over a wide range of carbon dioxide concentrations where it exhibited excellent response magnitudes, good linearity, and low detection limit. The synergistic effect can explain the obtained hybrid gas sensor’s prominent sensing properties between SnO2 and rGO that provide excellent charge transport capability and an abundance of sensing sites.

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