Activated carbon preparation from pistachio shell pyrolysis and gasification in a spouted bed reactor

Thapa

et al. 2019

Iodine and methylene blue adsorption properties of the high surface area nanoporous carbon materials derived from agro-waste and rice husk is reported. Rice husk was pre-carbonized at 300 °C in air followed by leaching out the silica nanoparticles by extraction with sodium hydroxide solution. The silica-free rice husk char was mixed with chemical activating agents sodium hydroxide (NaOH), zinc chloride (ZnCl2), and potassium hydroxide (KOH) separately at a mixing ratio of 1:1 (wt%) and carbonized at 900 °C under a constant flow of nitrogen. The prepared carbon materials were characterized by scanning electron microscopy (SEM), Fourier transformed-infrared spectroscopy (FT-IR), powder X-ray diffraction (pXRD), and Raman scattering. Due to the presence of bimodal micro- and mesopore structures, KOH activated samples showed high specific surface area ca. 2342 m2/g and large pore volume ca. 2.94 cm3/g. Oxygenated surface functional groups (hydroxyl, carbonyl, and carboxyl) were commonly observed in all of the samples and were essentially non-crystalline porous particle size of different sizes (<200 μm). Adsorption study revealed that KOH activated samples could be excellent material for the iodine and methylene blue adsorption from aqueous phase. Iodine and methylene blue number were ca. 1726 mg/g and 608 mg/g, respectively. The observed excellent iodine and methylene blue adsorption properties can be attributed to the well-developed micro- and mesopore structure in the carbon material. This study demonstrates that the agricultural waste, rice husk, and derived nanoporous carbon materials would be excellent adsorbent materials in water purifications.

Section: Introductionmentioning

confidence: 99%

Rice Husk-Derived High Surface Area Nanoporous Carbon Materials with Excellent Iodine and Methylene Blue Adsorption Properties

Thapa

et al. 2019

Chemical Engineering Journal

“…Spouted Beds (SB) continue to attract interest in recent years for a broad range of applications, mostly related to drying processes, due to the high fluid-solid contact achieved [1]. Spouted beds currently stand out as a promising technology to carry out thermo-chemical reactions such as pyrolysis [2,3], gasification [4,5] and combustion [6,7] of different materials, such as coal or waste products. A Spouted Bed can be described as a conventional fluidisation reactor in which the perforated plate has been replaced by single orifice place, promoting enhanced recirculation of solids with a particular multiphase pattern [8].…”

Section: Introductionmentioning

confidence: 99%

CFD simulation of a spouted bed: Comparison between the Discrete Element Method (DEM) and the Two Fluid Model (TFM)

Moliner

Marchelli

Nayia

et al. 2019

Highlights  A prismatic spouted bed was modelled using CFD.  A comparison between discrete element method (CFD-DEM) and two fluid model (CFD-TFM) was performed.  Results in terms of accuracy and computational effort were evaluated for each approach.  CFD-DEM provides a better prediction of maximum particle velocity.  CFD-TFM predicts better the height of the fountain. A spouted bed was simulated through two Computational Fluid Dynamic models: CFD-TFM and CFD-DEM. The two models were compared and validated with data from literature, showing good agreement between experimental and simulated results. Both models were able to predict the dynamics of the bed from the static situation to stable spouting conditions, even though some discrepancies in the solid volume fraction or velocity profiles were observed. Overall, CFD-DEM reproduced better the experimental measurements, and, since the computational effort was proved to be similar in both cases due to the low number of particles in the bed, it was preferred to describe the present spouted bed. In larger systems, however, CFD-DEM might not be so convenient, requiring the evaluation of the degree of accuracy and the computational costs prior to the application of this or alternative models.

“…In the past few years, porous crystalline metal organic frameworks (MOFs), 14,15 porous organic polymers (POPs), 16,17 silicon composite materials, [18][19][20] biomass-derived carbon materials, [21][22][23][24] graphene oxide, 25 Layered double hydroxide 26 as new types of functional materials with the relatively high capability to capture iodine, have aroused substantial interest in many researchers. These porous materials have a better capacity for adsorbing iodine compared with the silver-based adsorbents.…”

Section: Introductionmentioning

confidence: 99%

Rapid iodine capture from radioactive wastewater by green and low-cost biomass waste derived porous silicon–carbon composite

Han

et al. 2021

RSC Adv.