Preparação e caracterização de carvão ativado quimicamente a partir da casca de arroz

Abstract

PREPARATION AND CHARACTERIZATION OF CHEMICALLY ACTIVATED CARBON FROM RICE HULLS. This work consists in a study about the chemical activation of charred rice hulls using NaOH as the activation agent. The influence of the naturally-occurring silica was particularly evidenced. X-ray diffraction patterns showed the formation of sodium carbonate and silicates in the activated samples, whereas thermogravimetric curves revealed a strong reduction in the ash content of these samples after washing with water. Nitrogen adsorption data indicated a microporosity development only in the washed samples, with BET surface area values of 450 and 1380 m 2 /g achieved for the samples activated at 800 °C starting from the precursor with or without silica, respectively.

Produção e caracterização de carvão ativado produzido a partir do defeito preto, verde, ardido (PVA) do café

“…9 Os CA podem ser utilizados como materiais adsorventes no tratamento de água, no controle da emissão de poluentes, na purificação e armazenamento de gases, catalisadores e suportes catalíticos. 10,11 A produção de CA envolve duas etapas: a carbonização do precursor em atmosfera inerte e a ativação do material carbonizado. A etapa de carbonização consiste no tratamento térmico (pirólise) do precursor sob atmosfera inerte à temperatura, normalmente, superior a 473 K. É uma etapa de preparação do material na qual se removem componentes voláteis e gases leves (CO, H 2 , CO 2 e CH 4 ), produzindo uma massa de carbono fixo e uma estrutura porosa primária que favorece a ativação posterior.…”

Production and characterization of absorbent heat from the bark of residual Brazil nut bark (Bertholletia Excelsa l.)

“…It is observed in the isotherm a loop similar to the hysteresis type H4, which is related to the mechanism of condensation of N 2 in the mesopore. According to the IUPAC classification, this H4 hysteresis loop is associated with the presence of wedge-shaped micro and meso pores, cones and/or parallel plates and cylindrical capillaries open at both ends [25]. …”

Preparation and Microstructural Characterization of Activated Carbon-Metal Oxide Hybrid Catalysts: New Insights into Reaction Paths

“…1). The patterns show broad reflections of typically amorphous materials at 2θ = 24º and 2θ = 44º [32,33] . The asymmetric diffraction band in the range of 2θ from 40 to 47º reveals the turbostratic structure resulted from a low crystallite ordering of both carbon samples [34] .…”