Comparison of chemical and physical activation processes at obtaining adsorbents from Moroccan oil shale

Abstract

Within the Moroccan natural resources valorisation scheme, new adsorbents have been prepared from oil shale by chemical and physical activation processes. The activation process the authors have developed in this study give effective adsorbent materials. In view of the physico-chemical properties of these materials and application to the treatment of water loaded with a metal (Cr 6+ ion) or organic (methylene blue (MB)) pollutant, it is concluded that the chemical activation process of oil shale at low temperature (250 °C) affords the best material. The material's yield is good in comparison with the physical activation at the same temperature and the process is energy saving differently from that at 450 °C. Moreover, the chemical activation of oil shale with phosphoric acid at 250 °C produces a material with a good yield (about 70%), a high specific surface area (approximately 600 m 2 /g) and a highly porous structure, which gives it a high retention of methylene blue and the Cr 6+ ion.

Oil Shale of Rif region: natural adsorbents for environmental cleaning

“…X-ray diffraction analysis was done to determine the crystal structure of the prepared shale (fig. 2) shows that these are wellcrystallized materials characterized by a principal phase characteristic of quartz-SiO2 accompanied by other phases relating to metal oxides, the main one attributable to plagioclase (CaAl2Si2O8) [18]. Generally, clay forms most often layers in most deposits in the form of hydro-oxysilicates whose composition is very variable.…”

“…Fig.2: X-ray diffraction diagrams of oil shale in the Rif region steamed at 100°C. The structural study of the Tetouan, Bab-Taza, and Arba Ayacha oil shale (fig 2)shows that these are wellcrystallized materials characterized by a principal phase characteristic of quartz-SiO2 accompanied by other phases relating to metal oxides, the main one attributable to plagioclase (CaAl2Si2O8)[18].Generally, clay forms most often layers in most…”

Lignocellulosic Biomass-Derived Carbon Electrodes for Flexible Supercapacitors: An Overview

“…Among different chemical activation agents, KOH is the most widely used activation agent since it demonstrates the best activation effect to enhance the SSA up to >2000 m 2 /g [ 92 , 93 , 94 ]. The mechanism of KOH activation involves the etching of carbon skeleton for the expansion or creation of pores caused by the reactions at high temperature (>750 °C), as shown in Equations (4)–(7) [ 75 , 95 ]: …”

Effect of processing conditions on the improvement of properties and recovering yield of Moroccan oil shale

“…Besides, oil shale has some potential for the production of synthetic products such as cement, calcium, alumina, pitches, carbon adsorbents, zeolites, carbon fibers and other chemicals [5][6][7][8][9][10][11][12]. Those applications have generated, in recent years, many studies on methods for extracting these oils, such as pyrolysis by conventional heating or under microwave irradiation, extraction with solvents under sub-and supercritical conditions or combustion in fluidized bed reactors [13][14][15][16][17].…”