Role of pulping process as synergistic treatment on performance of agro-based activated carbons

Abstract

To recommend the beneficial effect of the pulping process on enhancing agro-wastes as precursors for the production of high-performance activated carbons (ACs), different pulping methods (alkali, sulfite and neutral sulfite) were applied on two available Egyptian agriculture by-products (rice straw and sugar cane bagasse), using the one-step pyrolysis method and H 3 PO 4 activating agent. The adsorption performance of the different prepared ACs was evaluated in terms of Iodine Numbers and their sorption properties for removing the methylene blue (MB) from aqueous solutions. The corresponding sorption processes were also analysed using Lagergren first order, pseudo-second order and intraparticle diffusion models. Data revealed that the applied pulping conditions were effective for removing the non-cellulosic constituents of agro-residues. This was demonstrated by the hydrogen/carbon and oxygen/carbon ratios, thermal stability and IR-measurements of the final pulps. These data were effective on the particular sorption properties of RS and SCB-based ACs. Interestingly, the pulping process is a profound modification of the SCB-based fibres, on which it induced a clear increase of the specific surface areas of the corresponding ACs even though they had an impact on the sorption of MB and iodine. These values are superior to the reported data on agro-based ACs with H 3 PO 4 activators. Pulping processes therefore play a dual role in the sorption properties of ACs. The first important role is the impact on the specific surface areas and the second impact is a profound modification of the surface chemistry of the ACs. Therefore, SCB-based ACs can be seen as an economical breakthrough product, and an alternative to the high-cost commercial ACs for the purification of industrial wastewaters.

Electiveness of agro-pulping process in the sustainable production of black liquor-based activated carbons

“…This study is carried out to indicate the trend of weight loss of BL versus carbonization temperature. The role of pulping processes on weight loss and consequently the char yield (weight remain) as a function of temperature are also examined in comparison with the studies previously performed on pulp fibres [35] and illustrated in figure 2 a – c . TGA and DTG curves show that at lower temperature (less than 120°C), the weight loss is related to evaporation of moisture contents; while at relatively higher temperatures (in the range 117–376°C), most of the organic components of BLs are thermally decomposed (volatilized), and leaving the comparable amount of chars.…”

“…The equilibrium and kinetic adsorption of MB dye on the BL-ACs of RS and SCB are studied, and the finding results are compared with previous data dealing with the ACs from RS and SCB pulps [35] (tables 4 and 5 and figure 7 b ). Table 4 shows the experimental data of the equilibrium adsorption using Langmuir and Freundlich models.…”

“…Figure 7a shows the adsorption of iodine on the surface of ACs, which are produced from black liquors of RS and SCB pulping processes. These values are also compared with those produced from previously synthesized pulp fibres [35]. It can be seen that BL-based AC from neutral sulfite pulping of RS shows royalsocietypublishing.org/journal/rsos R. Soc.…”

“…The types of pulping processes of RS (alkaline, acidic and neutral) are optimized and compared with BLs produced from sugar-cane bagasse (SCB). Moreover, the performance of BL-based ACs will be compared with previously produced ACs from RS and SCB pulp fibres [35]. The choice of SCB for comparison is based on this residue already being used in local paper mills for production of paper products.…”

Effective treatment for environmental enhancing the performance of undesirable agro‐waste in production of carbon nanostructures as adsorbent

“…Due to highly specific surface area, short diffusion distance, and tunable pore size with different surface functionalization, which characterized the CNSs as carbon nano‐adsorbents, thus they offer significant adsorption enhancement 20–21 . Moreover, highly performance activating carbons were prepared by using K 2 CO 3 as activating agent or blending it with inorganic‐based nanomaterials, for example, silica 8,22–24 …”