Hydrothermal Carbonization of Biomass for Energy and Crop Production

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
M. Toufiq Reza ◽  
Janet Andert ◽  
Benjamin Wirth ◽  
Daniela Busch ◽  
Judith Pielert ◽  
...  
Keyword(s):  
Crop Production ◽  
Power Plants ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Hydrothermal Carbonization ◽  
Toxic Substances ◽  
Carbon Nanospheres ◽  
Thermochemical Pretreatment ◽  
Hot Compressed Water

AbstractHydrothermal carbonization (HTC) is a thermochemical pretreatment process where biomass is treated under hot compressed water to produce hydrochar. Hydrochar is a stable, hydrophobic, friable solid product, which has a fuel value similar to that of lignite coal. Among its other advantages, its capability to handle wet feed makes the HTC process most attractive. The complex reaction chemistry of HTC offers a huge potential for producing a variety of products, from fuel to supercapacitors, from carbon nanospheres to low cost adsorbents, from fertilizers to soil amenders. Hydrochar opens possibilities for replacing coal in existing coal-power plants. Its high surface area and adsorption characteristics make it compatible for use in supercapacitors. Hydrochar also contains high amounts of stable carbon and other nutrients, which are essential for soil amendment. Moreover, the HTC process liquid, especially if a short retention time is used, contains potentially toxic substances like phenols, furfurals, and their derivatives, which open opportunities for anaerobic digestion to produce biogas. This review paper gives an overview of the HTC process parameters, reactions, and the use of hydrochar for energy and crop production

scholarly journals Facile Preparation of Porous Inorganic SiO2 Nanofibrous Membrane by Electrospinning Method

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Meng-Jie Chang ◽  
Wen-Na Cui ◽  
Jun Liu
Keyword(s):  
Electron Microscopy ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Electrospun Nanofibers ◽  
Nanofibrous Membrane ◽  
Carbon Nanospheres ◽  
Transmission Electron ◽  
Straightforward Method ◽  
One Step

We presented a straightforward method to fabricate porous inorganic SiO2 nanofibrous membrane by one-step calcination of electrospun nanofibers, which encapsulated with carbon nanospheres as template for nanopore generation. The structure, morphology, and composition of the as-spun fibers (PVA/SiO2/C) and porous SiO2 were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The detective results indicated that the carbon nanospheres were uniformly encapsulated inside the PVA/SiO2/C nanofibers. After calcination, PVA polymer was removed and high flexible inorganic nanofibrous membrane composed of amorphous SiO2 was obtained. Simultaneously, carbon nanosphere template was decomposed and uniform nanopores were generated inside the SiO2 nanofibers. This new method is simple and of low cost and hence is suitable to prepare other porous inorganic nanofibers with high surface area for practical application.

scholarly journals Synthesis of catalysts with fine platinum particles supported by high-surface-area activated carbons and optimization of their catalytic activities for polymer electrolyte fuel cells

RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20601-20611
Author(s):  
Md. Mijanur Rahman ◽  
Kenta Inaba ◽  
Garavdorj Batnyagt ◽  
Masato Saikawa ◽  
Yoshiki Kato ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Polymer Electrolyte ◽  
High Performance ◽  
Activated Carbons ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Polymer Electrolyte Fuel Cells ◽  
Supported Platinum ◽  
Platinum Particles

Herein, we demonstrated that carbon-supported platinum (Pt/C) is a low-cost and high-performance electrocatalyst for polymer electrolyte fuel cells (PEFCs).

scholarly journals Effects of Annealing Temperature on the Oxygen Evolution Reaction Activity of Copper–Cobalt Oxide Nanosheets

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 657
Author(s):  
Geul Han Kim ◽  
Yoo Sei Park ◽  
Juchan Yang ◽  
Myeong Je Jang ◽  
Jaehoon Jeong ◽  
...  
Keyword(s):  
High Activity ◽  
Cobalt Oxide ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Cobalt Hydroxide ◽  
Ni Foam ◽  
Electron Conduction

Developing high performance, highly stable, and low-cost electrodes for the oxygen evolution reaction (OER) is challenging in water electrolysis technology. However, Ir- and Ru-based OER catalysts with high OER efficiency are difficult to commercialize as precious metal-based catalysts. Therefore, the study of OER catalysts, which are replaced by non-precious metals and have high activity and stability, are necessary. In this study, a copper–cobalt oxide nanosheet (CCO) electrode was synthesized by the electrodeposition of copper–cobalt hydroxide (CCOH) on Ni foam followed by annealing. The CCOH was annealed at various temperatures, and the structure changed to that of CCO at temperatures above 250 °C. In addition, it was observed that the nanosheets agglomerated when annealed at 300 °C. The CCO electrode annealed at 250 °C had a high surface area and efficient electron conduction pathways as a result of the direct growth on the Ni foam. Thus, the prepared CCO electrode exhibited enhanced OER activity (1.6 V at 261 mA/cm2) compared to those of CCOH (1.6 V at 144 mA/cm2), Co3O4 (1.6 V at 39 mA/cm2), and commercial IrO2 (1.6 V at 14 mA/cm2) electrodes. The optimized catalyst also showed high activity and stability under high pH conditions, demonstrating its potential as a low cost, highly efficient OER electrode material.

Morphology dependent adsorption of methylene blue on trititanate nanoplates and nanotubes prepared by the hydrothermal treatment of TiO2

2016 ◽  
Vol 75 (2) ◽  
pp. 350-357
Author(s):  
Graham Dawson ◽  
Wei Chen ◽  
Luhua Lu ◽  
Kai Dai
Keyword(s):  
Methylene Blue ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Pore Volume ◽  
Hydrothermal Reaction ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
High Capacity ◽  
Adsorption Properties

The adsorption properties of two nanomorphologies of trititanate, nanotubes (TiNT) and plates (TiNP), prepared by the hydrothermal reaction of concentrated NaOH with different phases of TiO2, were examined. It was found that the capacity for both morphologies towards methylene blue (MB), an ideal pollutant, was extremely high, with the TiNP having a capacity of 130 mg/g, higher than the TiNT, whose capacity was 120 mg/g at 10 mg/L MB concentration. At capacity, the well-dispersed powders deposit on the floor of the reaction vessel. The two morphologies had very different structural and adsorption properties. TiNT with high surface area and pore volume exhibited exothermic monolayer adsorption of MB. TiNP with low surface area and pore volume yielded a higher adsorption capacity through endothermic multilayer adsorption governed by pore diffusion. TiNP exhibited a higher negative surface charge of −23 mV, compared to −12 mV for TiNT. The adsorption process appears to be an electrostatic interaction, with the cationic dye attracted more strongly to the nanoplates, resulting in a higher adsorption capacity and different adsorption modes. We believe this simple, low cost production of high capacity nanostructured adsorbent material has potential uses in wastewater treatment.

Highly active mixed-valent MnOxspheres constructed by nanocrystals as efficient catalysts for long-cycle Li–O2batteries

2016 ◽  
Vol 4 (43) ◽  
pp. 17129-17137 ◽  
Author(s):  
Sanpei Zhang ◽  
Zhaoyin Wen ◽  
Yang Lu ◽  
Xiangwei Wu ◽  
Jianhua Yang
Keyword(s):  
Surface Area ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Long Cycle ◽  
Highly Active

We demonstrate a low-cost and facile strategy to synthesize mixed-valent MnOxspheres constructed from nanocrystals (~5 nm), containing MnII, MnIII, and MnIVspecies. Such highly active mixed-valent MnOxspheres with high surface area greatly improve the performance of Li–O2batteries.

Influence of nanoparticles on the polymer-conditioned dewatering of wastewater sludges

2013 ◽  
Vol 67 (9) ◽  
pp. 2117-2123
Author(s):  
N. J. Boyle ◽  
G. M. Evans
Keyword(s):  
Activated Sludge ◽  
Titanium Dioxide Nanoparticles ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Wastewater Sludge ◽  
Small Scale ◽  
Sludge Dewatering ◽  
Solids Content ◽  
The Impact

The effect of using small-scale, high surface area, nanoparticles to supplement polymer-conditioned wastewater sludge dewatering was investigated. Aerobically digested sludge and waste activated sludge sourced from the Hunter Valley, NSW, Australia, were tested with titanium dioxide nanoparticles. The sludge samples were dosed with the nanoparticles in an attempt to adsorb a component of the charged biopolymer surfactants present naturally in sludge. The sludge was conditioned with a cationic polymer. The dewatering characteristics were assessed by measuring the specific resistance to filtration through a modified time-to-filter testing apparatus. The solids content of the dosed samples was determined by a mass balance and compared to the original solids content in the activated sludge. Test results indicated that nanoparticle addition modified the structure of the sludge and provided benefits in terms of the dewatering rate. The samples dosed with nanoparticles exhibited faster water removal, indicating a more permeable filter cake and hence more permeable sludge. A concentration of 2–4% nanoparticles was required to achieve a noticeable benefit. As a comparison, the sludge samples were also tested with a larger particle size, powdered activated carbon (PAC). It was found that the PAC did provide some minor benefits to sludge dewatering but was outperformed by the nanoparticles. The solids content of the final sludge was increased by a maximum of up to 0.6%. The impact of the order sequence of particles and polymer was also investigated. It was found that nanoparticles added before polymer addition provided the best dewatering performance. This outcome was consistent with current theories and previous research through the literature. An economic analysis was undertaken to confirm the viability of the technology for implementation at a full-scale plant. It was found that, currently, this technology is unlikely to be favourable unless the nanoparticles can be sourced for a low cost.

scholarly journals Green and facile synthesis of cerium doped Ni3Fe electrocatalyst for efficient oxygen evolution reaction

2020 ◽  
Vol 34 (2) ◽  
pp. 353-363
Author(s):  
F. Kanwal ◽  
A. Batool ◽  
R. Akbar ◽  
S. Asim ◽  
M. Saleem
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Large Scale ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Three Dimensional ◽  
Alkaline Electrolyte ◽  
Hydrogen Electrode ◽  
Molar Ratios

Electrochemical water splitting is the most promising pathway to produce high-purity hydrogen to alleviate global energy crisis. This reaction demands inexpensive, efficient and robust electrocatalyst for its commercial use. Herein, we demonstrate an effective, facile and scalable method for the synthesis of cerium doped Ni3Fe nanostructures as an electrocatalyst for oxygen evolution reaction (OER) by following simple chemical bath deposition route. The different molar ratios (3, 6 and 12 mM) of cerium in the chemical bath were used to study its effect on the structural and the electrochemical properties of the Ni3Fe nanostructured films. Doping of cerium contents induced variations in the morphology of deposited Ni3Fe nanostructures. The optimized electrocatalyst Ni3Fe/Ce-6 yielded high surface area catalyst nanosheets uniformly deposited on three-dimensional conductive scaffold to ensure increase in the exposure of doped Ni3Fe catalytic sites with high electrical conductivity. As a result, this earth-abundant electrocatalyst affords high OER performance with a small overpotential of 310 mV versus reversible hydrogen electrode (RHE) at 10 mA cm-2 and retains good stability up to ~ 10 h in alkaline electrolyte. This scalable strategy has great potential in future advancement of efficient and low-cost electrocatalysts for their large-scale application in energy conversion systems.                     KEY WORDS: Oxygen evolution, Electrocatalyst, Ni3Fe nanostructures, Cerium, Alkaline electrolyte   Bull. Chem. Soc. Ethiop. 2020, 34(2), 353-363 DOI: https://dx.doi.org/10.4314/bcse.v34i2.12

scholarly journals Recent Advances in Oxygen Electrocatalysts Based on Perovskite Oxides

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1161 ◽  
Author(s):  
Jun Xu ◽  
Chan Chen ◽  
Zhifei Han ◽  
Yuanyuan Yang ◽  
Junsheng Li ◽  
...  
Keyword(s):  
High Performance ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Precious Metals ◽  
Perovskite Oxides ◽  
Air Battery ◽  
Energy Conversion Devices ◽  
Further Development ◽  
Electrochemical Oxygen

Electrochemical oxygen reduction and oxygen evolution are two key processes that limit the efficiency of important energy conversion devices such as metal–air battery and electrolysis. Perovskite oxides are receiving discernable attention as potential bifunctional oxygen electrocatalysts to replace precious metals because of their low cost, good activity, and versatility. In this review, we provide a brief summary on the fundamentals of perovskite oxygen electrocatalysts and a detailed discussion on emerging high-performance oxygen electrocatalysts based on perovskite, which include perovskite with a controlled composition, perovskite with high surface area, and perovskite composites. Challenges and outlooks in the further development of perovskite oxygen electrocatalysts are also presented.

scholarly journals Removal of organic contaminant by municipal sewage sludge-derived hydrochar: kinetics, thermodynamics and mechanisms

2018 ◽  
Vol 78 (4) ◽  
pp. 947-956 ◽  
Author(s):  
Jia Wei ◽  
Yitao Liu ◽  
Jun Li ◽  
Hui Yu ◽  
Yongzhen Peng
Keyword(s):  
Sewage Sludge ◽  
High Surface ◽  
High Surface Area ◽  
Correlation Coefficients ◽  
Hydrothermal Carbonization ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Wide Range ◽  
Pseudo Second Order ◽  
Physical Interactions

Abstract In this work, a microporous municipal sewage sludge-derived hydrochar (MSSH) with relatively high surface area and abundant surface organic functional groups was produced through hydrothermal carbonization. Based on the adsorption results over a wide range of conditions, the prepared MSSH was suggested as a promising adsorbent for CV because of its high and efficient adsorption capability. The experimental data were fitted to several kinetic models. Based on calculated respective parameters such as rate constants, equilibrium adsorption capacities and correlation coefficients, the pseudo second-order model proved the best in describing the adsorption behavior of MSSH. Through kinetics, thermodynamic modeling studies and material characterization, a plausible adsorption process was discussed under the conditions used in this study. It can be confirmed that the adsorption of CV onto MSSH is via both physical interactions (electrostatic interaction and Van der Waals' force) and chemical interactions (formation of H-bonding).

scholarly journals Synthesis of activated carbon from biowaste of fir bark for methylene blue removal

2019 ◽  
Vol 6 (9) ◽  
pp. 190523 ◽  
Author(s):  
Lu Luo ◽  
Xi Wu ◽  
Zeliang Li ◽  
Yalan Zhou ◽  
Tingting Chen ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Activated Carbon ◽  
Nonlinear Models ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Raw Material ◽  
Maximum Adsorption Capacity ◽  
Koh Activation ◽  
Mb Adsorption

Activated carbon (AC) was successfully prepared from low-cost forestry fir bark (FB) waste using KOH activation method. Morphology and texture properties of ACFB were studied by scanning and high-resolution transmission electron microscopies (SEM and HRTEM), respectively. The resulting fir bark-based activated carbon (ACFB) demonstrated high surface area (1552 m 2 g −1 ) and pore volume (0.84 cm 3 g −1 ), both of which reflect excellent potential adsorption properties of ACFB towards methylene blue (MB). The effect of various factors, such as pH, initial concentration, adsorbent content as well as adsorption duration, was studied individually. Adsorption isotherms of MB were fitted using all three nonlinear models (Freundlich, Langmuir and Tempkin). The best fitting of MB adsorption results was obtained using Freundlich and Temkin. Experimental results showed that kinetics of MB adsorption by our ACFB adsorbent followed pseudo-second-order model. The maximum adsorption capacity obtained was 330 mg g −1 , which indicated that FB is an excellent raw material for low-cost production of AC suitable for cationic dye removal.

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