Preparation and characterization of activated carbons obtained from the waste materials impregnated with phosphoric acid(V)

AbstractIn the paper spent coffee grounds were used as a precursor to obtain activated carbons. The raw material was impregnated with phosphoric acid(V) at the different impregnations ratios: 0.5, 1, 1.5, 2. Carbonization was carried out according to two procedures differing in activation atmosphere (N2 or CO2). The obtained activated carbons were characterized on the basis of low-temperature nitrogen adsorption/desorption, thermal analysis, potentiometric titration method, X-ray diffraction, Raman spectroscopy and scanning electron microscopy. Carbons obtained according to procedure 2 (activation in CO2) were characterized by better developed porosity, e.g. surface (SBET to 720.9 m2/g) and pore volume (Vp to 0.334 cm3/g). All obtained carbons had surface acidic (mainly carboxyl) groups and exhibited the amorphous structure. The thermal analysis showed that the obtained materials were thermally stable up to the temperature ~ 420 °C.

Download Full-text

Synthesis and Characterization of Mesoporous Molecular Sieve Al-MCM-41 Using Kaolin as Raw Material

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.779-780.201 ◽

2013 ◽

Vol 779-780 ◽

pp. 201-204

Author(s):

Miao Li ◽

Hong Wang ◽

Xian Qing Li ◽

Jin Rong Liu

Keyword(s):

Molecular Sieve ◽

Nitrogen Adsorption ◽

Mesoporous Molecular Sieve ◽

Raw Material ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Adsorption Desorption ◽

Calcined Kaolin ◽

Mcm 41

Ordered hexagonally mesoporous molecular sieve Al-MCM-41 with Si/Al (atom) ratio=9 was prepared by hydrothermal synthesis using raw kaolin. X-ray diffraction (XRD), Nitrogen adsorption desorption, Transmission Electron Microscope (TEM) and Energy Dispersive X-ray Detector (EDX) were employed to characterise raw kaolin, calcined kaolin, as-synthesized and calcined Al-MCM-41. The results indicated that characteristic reflections of raw kaolin disappeared after calcination, both of as-synthesized and calcined Al-MCM-41 exhibited well ordered hexagonally mesoporous molecular sieve structure.

Download Full-text

Microwave radiation influence on the thermal and spectroscopic properties of Na-birnessite-type material

Cerâmica ◽

10.1590/0366-69132019653762653 ◽

2019 ◽

Vol 65 (376) ◽

pp. 547-553 ◽

Cited By ~ 2

Author(s):

T. C. C. Lavra ◽

L. A. Silva ◽

K. S. B. Cavalcante ◽

K. L. L. Marinho ◽

B. A. M. Figueira ◽

...

Keyword(s):

Thermal Analysis ◽

Raman Spectroscopy ◽

Microwave Radiation ◽

Nitrogen Adsorption ◽

Spectroscopic Properties ◽

Morphological Properties ◽

X Ray Diffraction ◽

Short Time ◽

Adsorption Desorption ◽

Ftir And Raman Spectroscopy

Abstract The aim of this work was to study the effect of the microwave radiation on the thermal and spectroscopic features, as well as about arrangement (order-disorder) and morphological properties, of the layered manganese oxide with birnessite-type structure. The route employed to obtain Na-birnessite matrix was redox precipitation. The products were characterized by X-ray diffraction, thermal analysis (TG-DTG-DSC), infrared (FTIR) and Raman spectroscopy, scanning electron microscopy (SEM) and nitrogen adsorption-desorption technique. The results showed that microwave radiation influenced in a short time (5 min) the octahedral ordering of birnessite, as well as in increasing the crystallite size. Thermal analysis showed that the thermal behavior of the lamellar matrix was different from that of birnessite under microwave radiation. After microwave-assisted hydrothermal treatment, FTIR and Raman spectroscopy investigations were used to differentiate ordered and disordered birnessites. Otherwise, there were no changes in SEM morphology of the lamellar-type phases, but the particle size changed.

Download Full-text

Optimization of Active Carbonaceous Material Obtained by Low Hydrothermal Carbonization of Plane Tree Seed with H3PO4

Journal of Nano Research ◽

10.4028/www.scientific.net/jnanor.48.71 ◽

2017 ◽

Vol 48 ◽

pp. 71-84

Author(s):

Vladimir Dodevski ◽

Branka Kaluđerović ◽

Sanja Krstić ◽

Vuk Spasojević ◽

Snežana Trifunović ◽

...

Keyword(s):

Activated Carbons ◽

Carbonaceous Material ◽

Nitrogen Adsorption ◽

Hydrothermal Carbonization ◽

Sem Analysis ◽

Raw Material ◽

Morphological Properties ◽

Plane Tree ◽

Adsorption Desorption ◽

Tree Seed

Activated carbons (ACs) were successfully prepared using plane tree seed (PTS) as a cheap and renewable raw material. The plane tree seeds were firstly treated combining magnetic (MM) and ultrasonic mixing (USM) during 0.5, 1 and 3 h in 1 M, 3 M and 6 M of H3PO4 solutions, and then activated at 260 °C during 20 h (low temperature hydrothermal carbonization–low HTC) in above mentioned solutions of the same molarity. The influence of combined mixing and activation processes on physical, structural and morphological properties, and their optimization was studied by X-ray powder diffraction (XRPD), Raman spectroscopy, nitrogen adsorption-desorption isotherms, fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis.

Download Full-text

Pore Modification and Phosphorus Doping Effect on Phosphoric Acid-Activated Fe-N-C for Alkaline Oxygen Reduction Reaction

Nanomaterials ◽

10.3390/nano11061519 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1519

Author(s):

Jong Gyeong Kim ◽

Sunghoon Han ◽

Chanho Pak

Keyword(s):

Phosphoric Acid ◽

Photoelectron Spectroscopy ◽

Structural Changes ◽

Electronic States ◽

Nitrogen Adsorption ◽

Reduction Reaction ◽

Phosphorus Doping ◽

X Ray ◽

Precious Metal Catalysts ◽

Adsorption Desorption

The price and scarcity of platinum has driven up the demand for non-precious metal catalysts such as Fe-N-C. In this study, the effects of phosphoric acid (PA) activation and phosphorus doping were investigated using Fe-N-C catalysts prepared using SBA-15 as a sacrificial template. The physical and structural changes caused by the addition of PA were analyzed by nitrogen adsorption/desorption and X-ray diffraction. Analysis of the electronic states of Fe, N, and P were conducted by X-ray photoelectron spectroscopy. The amount and size of micropores varied depending on the PA content, with changes in pore structure observed using 0.066 g of PA. The electronic states of Fe and N did not change significantly after treatment with PA, and P was mainly found in states bonded to oxygen or carbon. When 0.135 g of PA was introduced per 1 g of silica, a catalytic activity which was increased slightly by 10 mV at −3 mA/cm2 was observed. A change in Fe-N-C stability was also observed through the introduction of PA.

Download Full-text

Facile hydrothermal synthesis of Fe3O4 nanoparticle and effect of crystallinity on performances for supercapacitor

Functional Materials Letters ◽

10.1142/s179360471950019x ◽

2019 ◽

Vol 12 (02) ◽

pp. 1950019 ◽

Cited By ~ 6

Author(s):

Yue Xu ◽

Ying Zhang ◽

Xiaolan Song ◽

Hanjun Liu

Keyword(s):

Hydrothermal Method ◽

Reaction Times ◽

Amorphous Structure ◽

Electrochemical Performances ◽

X Ray Diffraction ◽

Oxide Electrode ◽

Facile Hydrothermal Method ◽

X Ray ◽

Pseudocapacitive Behavior ◽

Adsorption Desorption

Fe3O4 nanoparticles were synthesized by a facile hydrothermal method using triethanolamine. Effects of reaction times (2–8[Formula: see text]h) on crystallinity and electrochemical performances of Fe3O4 were investigated. Samples were analyzed by X-ray diffraction, infrared spectroscopy, N2 adsorption–desorption, scanning electron microscope, galvanostatic charge/discharge, and cyclic voltammetry. Results showed that the crystallinity of Fe3O4 was increased with hydrothermal time, and the sample prepared at 2[Formula: see text]h displayed amorphous structure with small grain size and large surface area of 165.0[Formula: see text]m2[Formula: see text]g[Formula: see text]. The sample exhibited typical pseudocapacitive behavior with capacitance of 383.2[Formula: see text]F[Formula: see text]g[Formula: see text] at 0.5 Ag[Formula: see text] in Na2SO3 electrolyte. After 2000 cycles, the capacitance retention of Fe3O4 at 2[Formula: see text]h was recorded as 83.6%, much higher than 26.3% for sample at 8[Formula: see text]h. It indicated that hydrothermal method was an effective approach to obtain amorphous Fe3O4, implying the potential application for preparing metal oxide electrode for supercapacitors.

Download Full-text

Application of raw and modified Uruguayan clays to phosphate adsorption for water remediation

MRS Advances ◽

10.1557/adv.2018.586 ◽

2018 ◽

Vol 3 (61) ◽

pp. 3543-3549

Author(s):

Pablo González ◽

Andrea C. De Los Santos ◽

Jorge R. Castiglioni ◽

María A. De León

Keyword(s):

Nitrogen Adsorption ◽

Pillared Clay ◽

Water Remediation ◽

Phosphate Adsorption ◽

X Ray Diffraction ◽

Order Model ◽

Freundlich Model ◽

X Ray ◽

First Order ◽

Adsorption Desorption

ABSTRACTA raw clay from Uruguay was modified with aluminium to obtain an aluminium pillared clay (Al-PILC). The solids were characterized by scanning electron microscopy, X-ray diffraction and nitrogen adsorption-desorption isotherms. The Al-PILC retained the typical laminar structure of montmorillonite. The specific surface area and the microporous volume of the Al-PILC, 235 m2 g-1 and 0.096 cm3 g-1, respectively, were much higher than those of the clay. The phosphate adsorption capacity of the Al-PILC was higher than those of the clay. The phosphate adsorption kinetic followed the pseudo-first-order model for both, the clay and the Al-PILC, and the phosphate adsorption isotherm for the Al-PILC fit the Freundlich model.

Download Full-text

Highly Porous Carbon Materials Filled with Nickel Hydroxide Nanoparticles; Synthesis, Study, Application in Electrochemistry

Eurasian Chemico-Technological Journal ◽

10.18321/ectj243 ◽

2015 ◽

Vol 17 (3) ◽

pp. 187 ◽

Cited By ~ 1

Author(s):

Yu.A. Zakharov ◽

A.N. Voropay ◽

N.M. Fedorova ◽

V.M. Pugachev ◽

A.V. Puzynin ◽

...

Keyword(s):

Porous Carbon ◽

Nickel Hydroxide ◽

Nitrogen Adsorption ◽

Porous Carbon Material ◽

X Ray Diffraction ◽

Scanning Rate ◽

Electrode Cell ◽

Adsorption Desorption ◽

Electrode Characteristics ◽

Study Application

Nickel hydroxide was deposited on the surface of the porous carbon to obtain a cathode material for supercapacitors. This work is the first part of the study of Ni(OH)2/С composite, which considers the conditions of its synthesis using two types of porous carbon matrices with a highly developed specific surface area (1000–3000 m2/g) and two types of precursors (NiCl2*6H2O and Ni(N3)2). The morphology of the systems, in particular the shape and size characteristics of the hydroxide filler particles, was examined using the scanning electron microscopy, X-ray diffraction, and nitrogen adsorption-desorption at 77 K. The measurements of capacity of the Ni(OH)2/С-electrodes were made in 6 M KOH using an asymmetric two-electrode cell (a porous carbon material with known electrode characteristics was employed as the counter electrode). The capacity was shown to decrease by 22–56% with increasing the scanning rate from 10 to 80 mV/s. A maximum capacity of the composite was obtained at a scanning rate of 10 mV/s was 346 F/g.

Download Full-text

Structural and surface aspects of thermally treated copper aluminium mixed hydroxides

Canadian Journal of Chemistry ◽

10.1139/v91-223 ◽

1991 ◽

Vol 69 (10) ◽

pp. 1511-1515 ◽

Cited By ~ 5

Author(s):

Awad I. Ahmed ◽

S. E. Samra ◽

S. A. El-Hakam

Keyword(s):

Pore Structure ◽

Copper Content ◽

Textural Properties ◽

Nitrogen Adsorption ◽

Phase Changes ◽

X Ray Diffraction ◽

X Ray ◽

Surface Areas ◽

Structure Surface ◽

Adsorption Desorption

CuO–Al2O3 catalysts containing various amounts of copper oxide have been prepared by precipitation. The phase changes were studied by X-ray diffraction. The results obtained revealed that the thermal treatment of solid CuO–Al2O3 at 700 °C produced only crystalline CuO. Heating to 900 °C led to the formation of copper alumina spinel together with unreacted CuO and γ-Al2O3. The spinel content was found to increase with increasing copper content. Nitrogen adsorption–desorption isotherms on the calcined samples have been measured. Surface areas have been calculated and the pore structure analysed. The textural properties of the system were found to depend on both the copper content and the calcination temperature. Key words: CuO, Al2O3 catalysts, structure, surface area, pore structure.

Download Full-text

Removal of Cu, Fe, and Zn from Peat Water by Using Activated Carbon Derived from Oil Palm Leaves

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1162.65 ◽

2021 ◽

Vol 1162 ◽

pp. 65-73

Author(s):

Rakhmawati Farma ◽

Ona Lestari ◽

Erman Taer ◽

Apriwandi ◽

Minarni ◽

...

Keyword(s):

Heavy Metal ◽

Activated Carbon ◽

Oil Palm ◽

Activated Carbons ◽

Nitrogen Adsorption ◽

Surface Characteristics ◽

Batch Adsorption ◽

X Ray ◽

Turbidity Level ◽

Adsorption Desorption

Heavy metal such as Cu, Fe, and Zn are the most serious contributers to environmental problems. The removal of heavy metal from the environment is the research interest nowdays. The adsorption of Cu, Fe and Zn from wastewater was investigated with various activated carbons as adsorbents. The activated carbons were produced from oil palm leaves by using multi-activation methods. The H3PO4, NaOH, ZnCl2 and KOH were chosen as chemical activating agents. Batch adsorption experiment was used to test the ability of activated carbon to remove Cu, Fe, and Zn from wastewater. The surface characteristics of activated carbon were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption-desorption isotherms. The Activated carbons were able to purify wastewater with a maximum turbidity level of 2.83 NTU. The AC-H3PO4 activated carbon showed the highest absorbability of Cu metal as 91.540%, while the highest absorbabilities of Zn and Fe metals were indicated by AC-KOH activated carbon of 22.853% and 82.244% absorption respectively. Therefore, these results enable the oil palm leaves to become a high potential for activated carbon as removal the heavy metals.

Download Full-text

Bulk Versus Surface Modification of Alumina with Mn and Ce Based Oxides for CH4 Catalytic Combustion

Materials ◽

10.3390/ma12111771 ◽

2019 ◽

Vol 12 (11) ◽

pp. 1771 ◽

Cited By ~ 2

Author(s):

Stefan Neatu ◽

Mihaela M. Trandafir ◽

Adelina Stănoiu ◽

Ovidiu G. Florea ◽

Cristian E. Simion ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Catalytic Combustion ◽

Mixed Oxides ◽

Sol Gel ◽

Nitrogen Adsorption ◽

X Ray Diffraction ◽

X Ray ◽

Temperature Programmed ◽

Catalytic Combustion Of Methane ◽

Adsorption Desorption

This study presents the synthesis and characterization of lanthanum-modified alumina supported cerium–manganese mixed oxides, which were prepared by three different methods (coprecipitation, impregnation and citrate-based sol-gel method) followed by calcination at 500 °C. The physicochemical properties of the synthesized materials were investigated by various characterization techniques, namely: nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and H2–temperature programmed reduction (TPR). This experimental study demonstrated that the role of the catalytic surface is much more important than the bulk one. Indeed, the incipient impregnation of CeO2–MnOx catalyst, supported on an optimized amount of 4 wt.% La2O3–Al2O3, provided the best results of the catalytic combustion of methane on our catalytic micro-convertors. This is mainly due to: (i) the highest pore size dimensions according to the Brunauer-Emmett-Teller (BET) investigations, (ii) the highest amount of Mn4+ or/and Ce4+ on the surface as revealed by XPS, (iii) the presence of a mixed phase (Ce2MnO6) as shown by X-ray diffraction; and (iv) a higher reducibility of Mn4+ or/and Ce4+ species as displayed by H2–TPR and therefore more reactive oxygen species.

Download Full-text