scholarly journals Preparation and characterization of modified corn stalk biochar

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 7428-7443
Author(s):  
Haifeng Zuo ◽  
Xianxian Qin ◽  
Zhigao Liu ◽  
Yunlin Fu

To increase the added value of corn stalk and improve the performance of corn stalk biochar, magnesium chloride (MgCl2) was used to modify biochar, and the effects of temperature on the structure and properties of modified biochar were considered. With the increase of temperature, the yield of biochar decreased. There was a marked increase in the number of mesopores and micropores, but the mesopore pore diameter changed to a smaller pore diameter, and the specific surface area remarkably increased. As the temperature increased, the content of C increased, while the range of H and O decreased. In addition, the number of oxygen-containing functional groups and methyl groups decreased, indicating that the structure of biochar became more aromatized. An obvious Mg(OH)2 crystal peak appeared in the X-ray diffraction pattern, which meant that Mg ions were loaded on the surface of biochar. Moreover, the highest removal rate of methylene blue dye by biochar was 83.6%. The authors conclude that temperature and magnesium chloride modification can improve and enhance the performance of corn stalk biochar. These findings will help deepen people’s understanding of biochar modification and serve as a reference for future related research.

Author(s):  
S. Louki ◽  
N. Touach ◽  
A. Benzaouak ◽  
V. M. Ortiz-Martínez ◽  
M. J. Salar-García ◽  
...  

This work investigates the photocatalytic activity of new ferroelectric material with formula (Li0.95Cu0.15)Ta0.76Nb0.19O3 (LT76) in a single chamber microbial fuel cell (MFC) and compares its performance with the similar photocatalyst (Li0.95Cu0.15)Ta0.57Nb0.38O3 (LT57). The photocatalysts LT76 and LT57 were synthesized by ceramic route under the same conditions, with the same starting materials. The ratio Ta/Nb was fixed at 4.0 and 1.5 for LT76 and LT57, respectively. These phases were characterized by different techniques including X-ray diffraction (XRD), transmission electronic microscopy (TEM), particle size distribution (PSD), differential scanning calorimetry (DSC), and ultraviolet (UV)–visible (Vis). The new photocatalyst LT76 presents specific surface area of 0.791 m2/g and Curie temperature of 1197 °C. The photocatalytic efficiency of this material is assessed in terms of wastewater treatment and electricity generation by power density and removal rate of chemical oxygen demand (COD) in the presence of a light source. The values of maximum power density and COD removal were 19.77 mW/m3 and 93%, respectively, for LT76.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Fiza Akram ◽  
Muhammad Saeed ◽  
Javaid Akhtar ◽  
Syed Ali Raza Naqvi ◽  
Atta ul Haq

Abstract This study reports the fabrication of Fe2O3, Bi2O3, and BiFeO3, characterization and evaluation of the photocatalytic performances for methylene blue dye degradation. The materials were synthesized by precipitation method and characterized by scanning electron microscopy, X-ray diffraction, energy dispersive X-rays analyses, and Fourier transform infrared analyses. The photocatalytic activities of Fe2O3, Bi2O3, and BiFeO3 were compared by performing degradation experiments with 50 mL of 100 mg/L methylene blue solution. The as-prepared BiFeO3 was found as 2.4 times and 1.7 times more effective than Fe2O3 and Bi2O3, with a 79, 47, and 57% catalytic activity, respectively. The degradation of methylene blue over the BiFeO3 catalyst was optimized in terms of pH, catalyst dosage, temperature, and methylene blue concentration. The Eley–Rideal mechanism was proposed to describe the reaction kinetics in terms of the first order and second order kinetics model. Activation energy E (kJ/mol), enthalpy ΔH (kJ/mol), entropy ΔS (J/mol) and free energy ΔG (kJ/mol) were calculated as 20.8, 18.2, 197.5 and −45.3 respectively. The negative value of free energy shows that photodegradation is favored in present conditions.


2011 ◽  
Vol 287-290 ◽  
pp. 1675-1679
Author(s):  
Hong Shao ◽  
Ning Cao

A series of sodium bentonites and cetyl tri methyl ammonium bromide as raw materials were prepared to the modified organic composite montmorillonites. The performance characterization of the modified organic bentonite was observed by means of IR spectroscopy, X-ray diffraction, scanning electron microscopy. And the modified organic bentonite was applied into the pretreatment of landfill leachate, which was with the COD as high as 20000-37000 mg/L. The COD removal rate was invested as index. The optimum dosage and the best reaction conditions of bentonite have also been studied. The results indicated that the treatment effect of COD on the modified bentonite was better than the natural bentonite. Under the optimum conditions, the removal rate of COD reached 67.85% and the load of biological treatment was reduced on the next step.


2016 ◽  
Vol 881 ◽  
pp. 35-40
Author(s):  
Franciele Oliveira Costa ◽  
Carla Gabriela Azevedo Misael ◽  
André Miranda da Silva ◽  
Bianca Viana de Sousa

The mesoporous silica SBA-15 molecular sieve has been widely studied due to its unidirectional mesoporous structure, its high average pore diameter, its high thermal and hydrothermal stability and its ability to absorb metal ions, allowing its use as support material for catalysts. This study aimed to synthesize the Co/SBA-15 catalyst, and characterize it through the techniques of X-ray diffraction, temperature programmed reduction (TPR) and scanning electron microscopy (SEM). The SBA-15 support was synthesized from the following molar composition of reaction mixture: 1TEOS: 0.017 P123: 5.7 HCl: 173 H2O: 40 EtOH, and after calcined at 550 °C for 6 hours. The Co/SBA-15 catalyst was prepared by incorporating 10% cobalt by wet impregnation. Through the X-ray diffractograms, it was found that the impregnation has not changed the structure of the material. RTP profiles showed the presence of peaks at different temperatures that may be caused by dispersion of the cobalt.


Author(s):  
Lorena Cuéllar-Herrera ◽  
Elsa Arce-Estrada ◽  
Antonio Romero-Serrano ◽  
José Ortiz-Landeros ◽  
Román Cabrera-Sierra ◽  
...  

AbstractTwo hydrothermal techniques under microwave irradiation were used to synthesize γ-MnO2 from 90°C to 150°C in 10−30 min. The first technique is based on reducing KMnO4 with MnSO4, and the second one involves liquid-phase oxidation between MnSO4 and (NH4)2S2O8. The structures and morphologies of the samples were analyzed using X-ray diffraction, scanning electron microscopy, and N2 physisorption measurements. The electrochemical properties were evaluated through cyclic voltammetry and electrochemical impedance spectroscopy. The γ-MnO2 materials obtained by the first technique mainly exhibited nanorods with diameters of 40–60 nm, and the samples obtained by the second technique showed flower-like microspheres with diameters of 1−2 µm; each flower was composed of nanosheets with a thickness of 10−20 nm. The processing time directly depends on the size of the nanorods. The sample synthesized by the first technique at 150°C and 10 min has the highest specific surface area of up to 59.08 m2 g−1 and mean pore diameter of 34.11 nm. Furthermore, this sample exhibits a near-rectangular cyclic voltammetry curves and high specific capacitance of 331.3 F g−1 in 0.1 M Na2SO4 solution at 5 mV s−1 scan rate. Graphic abstract


2014 ◽  
Vol 941-944 ◽  
pp. 216-220
Author(s):  
Li Zhu ◽  
Yan Qin Lu ◽  
Zhao Ju He

In this paper, Iron-Oxide-Coated-Zeolite has been prepared by using natural zeolite and ferric nitrate. The morphology and structure of the adsorbent were Characterized by Scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and Fourier transform infrared spectrometer (FTIR). The results show that the adsorption properties of zeolite were improved by modified with ferric nitrate. The phosphorus removal rate on IOCZ50was above 80%.


Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 452 ◽  
Author(s):  
Sayed Mukit Hossain ◽  
Heeju Park ◽  
Hui-Ju Kang ◽  
Jong Beom Kim ◽  
Leonard Tijing ◽  
...  

The purpose of the study was to effectively treat algae bloomed water while using a Ti-based coagulant (TiCl4) and recover photoactive novel anatase TiO2 from the flocculated sludge. Conventional jar tests were conducted in order to evaluate the coagulation efficiency, and TiCl4 was found superior compared to commercially available poly aluminum chloride (PAC). At a dose of 0.3 g Ti/L, the removal rate of turbidity, chemical oxygen demand (COD), and total phosphorus (TP) were measured as 99.8%, 66.7%, and 96.9%, respectively. Besides, TiO2 nanoparticles (NPs) were recovered from the flocculated sludge and scanning electron microscope (SEM), energy dispersive X-ray spectroscope (EDX), and X-ray diffraction (XRD) analysis confirmed the presence of only anatase phase. The recovered TiO2 was found to be effective in removing gaseous CH3CHO and NOx under UV-A lamp at a light intensity of 10 W/m2. Additionally, the TiO2 mixed mortar blocks that were prepared in this study successfully removed atmospheric nitrogen oxide (NOx) under UV irradiance. This study is one of the first to prepare anatase TiO2 from flocculated algal sludge and it showed promising results. Further research on this novel TiO2 concerning internal chemical bonds and shift in the absorbance spectrum could explore several practical implications.


2009 ◽  
Vol 67 ◽  
pp. 197-202 ◽  
Author(s):  
Kuldeep Rana ◽  
Anjan Sil ◽  
Subrata Ray

Carbon nanotubes (CNTs) have been synthesized by chemical decomposition of acetylene gas at 580°C and 650°C using catalyst of LiNi0.5Co0.5O2. The effect of decomposition temperature on structure of the CNTs is that, CNTs grown at 650°C have lower defects concentration and higher crystallinity as compared to that grown at 580°C. The porous anodized aluminum oxide (AAO) template (as substrate), catalyst particles and the CNTs grown were analyzed by FE-SEM. The pore diameter in the template lies in range of 30 - 80 nm. The CNTs have been analyzed by using Raman spectroscopy and X-ray diffraction techniques. The up-shift in G-band of graphitic sheet and larger full width at half maximum of the peak in the Raman spectra of the CNT in comparison to those observed for graphite are indicative of the structural modification. XRD results also indicate the structural modification in CNT based on the fact that d-value becomes 3.42 Å, which is larger than 3.35 Å for graphite. The tube diameters lie in the range of 12 - 50 nm.


2013 ◽  
Vol 800 ◽  
pp. 406-410
Author(s):  
Bao Song Li ◽  
Wei Wei Zhang

Polyaniline nanotubes were prepared by electrochemical polymerization polyaniline within the pores of AAO templates and have been open on one ends. The outside diameter of these tubes is determined by the pore diameter in the template used and that the length of the tube is determined by the thickness of the template. Influencing factors include the polymerization potential, current, scanning rates and numbers, solutions. The characterization of the resulting materials was carried out by UV-vis, X-ray diffraction, cyclic voltammetry, scanning lectron microscopy and conductivity measurements.


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Charitha Thambiliyagodage ◽  
Ramanee Wijesekera ◽  
Martin G. Bakker

AbstractNaturally available ilmenite mineral is being used as a starting material to produce titanium based products that have wide applications. Transformation of ilmenite to different titanium based materials by strong and weak acid, and base digestion, is discussed. Effects of temperature, concentration of acid/base, reaction time on dissolution of ilmenite are extensively reviewed. Characterization of the starting materials, intermediates and the products by x-ray diffraction, thermogravimetry, brunauer–emmett–teller surface area analysis, and scanning electron microscopy are presented. Further, advantages and disadvantages associated with the digestion methods are discussed.


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