scholarly journals Chemically Dual-Modified Biochar for the Effective Removal of Cr(VI) in Solution

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 39
Author(s):  
Juanjuan Yang ◽  
Yu Song ◽  
Yan Yue ◽  
Wenfei Liu ◽  
Quande Che ◽  
...  
Keyword(s):  
Physical Adsorption ◽  
Reduction Reaction ◽  
Aqueous Environment ◽  
Complexation Reaction ◽  
Modified Biochar ◽  
Activated Biochar ◽  
Removal Capacity ◽  
Effective Removal ◽  
Chloride Hexahydrate ◽  
Aluminum Chloride Hexahydrate

Here, a dual-modification strategy using KMnO4 (potassium permanganate) and AlCl3·6H2O (aluminum chloride, hexahydrate) as co-modifiers to improve the Cr(VI) removal capacity of K2CO3 activated biochar is introduced. As a result, the dual-modified biochar with KMnO4 and AlCl3·6H2O has the calculated adsorption energy of −0.52 eV and −1.64 eV for HCrO4−, and −0.21 eV and −2.01 eV for Cr2O72−. The Al2O3 (aluminum oxide) and MnO (manganese oxide) embedded on the surface of dual-modified biochar bring more Cr(VI) absorption sites comparing to single-modified biochar, resulting in a maximum Cr(VI) saturated adsorption capacity of 152.86 mg g−1. The excellent removal performance is due to the synthetic effect of electrostatic attraction, reduction reaction, complexation reaction, and physical adsorption. The experimental results also indicated that the spontaneous adsorption process agreed well with the pseudo-second order and Langmuir models. This dual-modification strategy is not limited to the treatment of Cr(VI) with biochar, and may also be incorporated with the treatment of other heavy metals in aqueous environment.

scholarly journals A Novel and Efficient Method for the Synthesis of Methyl (R)-10-Hydroxystearate and FAMEs from Sewage Scum

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 663
Author(s):  
Luigi di Bitonto ◽  
Valeria D’Ambrosio ◽  
Carlo Pastore
Keyword(s):  
Fatty Acid Methyl Esters ◽  
Methyl Esters ◽  
Enantiomeric Excess ◽  
Single Step ◽  
Acid Catalysts ◽  
Acid Methyl ◽  
Chloride Hexahydrate ◽  
Catalyst Temperature ◽  
Homogeneous Acid ◽  
Aluminum Chloride Hexahydrate

In this work, the transesterification of methyl estolides (ME) extracted from the lipid component present in the sewage scum was investigated. Methyl 10-(R)-hydroxystearate (Me-10-HSA) and Fatty Acid Methyl Esters (FAMEs) were obtained in a single step. A three-level and four factorial Box–Behnken experimental design were used to study the effects of methanol amounts, catalyst, temperature, and reaction time on the transesterification reaction using aluminum chloride hexahydrate (AlCl3·6H2O) or hydrochloric acid (HCl) as catalysts. AlCl3·6H2O was found quite active as well as conventional homogeneous acid catalysts as HCl. In both cases, a complete conversion of ME into Me-10-HSA and FAMEs was observed. The products were isolated, quantified, and fully characterized. At the end of the process, Me-10-HSA (32.3%wt) was purified through a chromatographic separation and analyzed by NMR. The high enantiomeric excess (ee > 92%) of the R-enantiomer isomer opens a new scenario for the valorization of sewage scum.

scholarly journals From Clay Minerals to Al2O3 Nanoparticles: Synthesis and Colloidal Stabilization for Optoelectronic Applications

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 118 ◽  
Author(s):  
Yesica L. Botero ◽  
Jorge Eliécer López-Rendón ◽  
Daniel Ramírez ◽  
Dioni Mabel Zapata ◽  
Franklin Jaramillo
Keyword(s):  
Particle Size ◽  
Aluminum Chloride ◽  
Perovskite Solar Cells ◽  
Acid Leaching ◽  
Colloidal Dispersion ◽  
Al2o3 Nanoparticles ◽  
Chloride Hexahydrate ◽  
Optoelectronic Applications ◽  
Aluminum Chloride Hexahydrate ◽  
Clay Materials

This research was performed to obtain high-value products from clay materials. High-grade nanometric delta-alumina (δ-Al2O3) was obtained from the modification of clay-based minerals, which could be potentially applied in the form of thin film for novel optoelectronic applications. The selective recovery process of alumina from clay materials presents an important advantage regarding the complete removal of other starting constituents such as silica, iron, titanium, alkali, and alkaline earth metals. To accomplish the selective removal of different species, an acid leaching route was used to extract the aluminum, then the iron impurities were eliminated by alkaline precipitation. The solution was acidized to precipitate the aluminum as aluminum chloride hexahydrate. Finally, the aluminum chloride hexahydrate was calcinated to obtain nano-delta-alumina with purity of over 98.5% Al2O3. The dominating crystalline phase was delta–gamma alumina (δ-phase and γ-phase), with a particle size of <140 nm. Then, these nanoparticles (NPs) were prepared as a stable colloidal dispersion to form a mesoporous layer employing the spin-coating technique. Initially, the synthesized alumina was characterized by atomic force microscopy (AFM) and TEM to determine the particle size and its morphology, whereas the colloidal dispersion was analyzed by rheological measurements. Finally, the findings of this investigation made it possible to get thin films with good porosity, which can be used in optoelectronic applications, specifically in perovskite solar cells.

Potential Evaluation of Gray Clay as Adsorbent of Heavy Metals Zinc (II) and Lead (II)

2014 ◽  
Vol 798-799 ◽  
pp. 622-627
Author(s):  
Wellington Siqueira Lima ◽  
José Vanderley Nascimento Silva ◽  
Aline Cadigna Lima Patrício ◽  
Guilherme Costa Oliveira ◽  
Meiry Glaúcia Freire Rodrigues
Keyword(s):  
Heavy Metals ◽  
Factorial Design ◽  
Metal Removal ◽  
Physical Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Removal Capacity ◽  
Adsorption Of Nitrogen ◽  
Potential Evaluation ◽  
Good Percentage

The problems caused by contamination of heavy metals generate a growing need to implement technologies to reduce or eliminate them. This work aims to evaluate the potential of gray clay, the process of removal of zinc and lead from synthetic effluents in finite bath system. The clay was characterized by: X-ray diffraction, X-ray Spectroscopy Energy Dispersive and Physical Adsorption of Nitrogen. The tests were performed finite bath following a 22 factorial design, with the variables: pH and initial concentrations of metal. The clays were evaluated for their removal capacity and rate of metal removal. After the characterization and evaluation, it was found that the gray clay comprises clay of the groups of kaolinite and mica. The results of the factorial design shown that the adsorption of the metals zinc and lead can be developed with good percentage of removal.

Synthesis, Structure and Electrochemical Behavior of a Supramolecular Compound

2009 ◽  
Vol 79-82 ◽  
pp. 1475-1478
Author(s):  
Zhi Feng Lin ◽  
Shu Fang Zhang ◽  
Dun Zhang
Keyword(s):  
Infrared Spectra ◽  
Elemental Analysis ◽  
Electrochemical Behavior ◽  
Reduction Reaction ◽  
Aqueous Environment ◽  
Cyclic Voltammograms ◽  
Supramolecular Compound ◽  
Uv Spectrum ◽  
Vibration Absorption ◽  
Stretching Vibration

A supramolecular compound, Co(C5H4NCOO)2(H2O)2∙2H2O was hydrothermally synthesized and characterized by elemental analysis, infrared spectra, UV-vis spectra. Elemental analysis result shows that the mass percent of C is 38.36%; H, 4.32% and N, 7.50%. Infrared spectra show that the main absorption peak is near 3396 cm-1, which is attributed to the O-H stretching vibration absorption. Also there are some absorption peaks at 1599, 1551, 1420, 1384 cm-1, which are attributed to the pyridine vibration absorption. UV spectrum for the compound shows strong absorption peaks at 203 and 259 nm, which are similar to isoniazid. X-ray diffraction data indicate that the compound is monoclinic, P21 / c space group. The cyclic voltammograms indicate that the compound decreases the rate of oxygen reduction reaction (ORR) and induces the ORR more difficult in aqueous solutions. The electrochemical behavior suggests that the compound possesses the potential application for corrosion in aqueous environment.

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