Optimizing the route for production of activated carbon fromCasuarina equisetifoliafruit waste

Abstract

This work deals with optimizing the conditions of pyrolysis and type of activator to upgrade the use of Casuarina equisetifolia fruit waste (CFW) as available and a potential precursor, in production of activated carbon (AC). In this respect, the route of activation was carried out through one- and two-step pyrolysis processes, using different chemical activating agents, such as H3PO4, KOH and ZnCl2. The performance of the CFW-based ACs is assessed by estimating the physico-chemical characteristics (pH, electrical conductivity, bulk density and hardness), surface morphology and scanning electron microscopy, together with carbon yield, surface area and adsorption performance of pollutants in aqueous medium (methylene blue, iodine and molasses colour removal efficiencies). The results show that the two-step activation process was more effective than one-step activation for providing high adsorption performance CFW-based ACs. The maximum Brunauer–Emmett–Teller surface area 547.89 m2 g−1 was produced by using H3PO4 activating agents, and applied two-step pyrolysis. According to the American Water Work Association and based on bulk density of the investigated ACs, we recommend that most of produced ACs are suitable for treating waste water.

RETRACTED: Activated Carbons From Winemaking Biowastes for Electrochemical Double-Layer Capacitors

“…A large number of pores can be observed, caused by the chemical interaction between the precursor surface and the activation agent (KOH). The obtained pores were irregular and oval, like embedded deep holes typically observed after chemical activation (El-Naggar et al, 2015 ; Ravichandran et al, 2018 ). BAG images denote areas with material agglomerates, where porosity is found between these mass portions.…”

Production and characterisation of activated carbon and carbon nanotubes from potato peel waste and their application in heavy metal removal.

“…Heidari et al prepared ACs with high surface area (2595 m 2 g −1 ) using H 3 PO 4 as a first activating agent followed by KOH as a second activating agent (Heidari et al 2014). It was mentioned that a two-step activation method produces up to 25% higher carbon yields activated carbon than that of a single-step activation method along with 50% higher surface area and pore volume also (Ravichandran et al 2018).…”

Upcycling brewer's spent grain waste into activated carbon and carbon nanotubes for energy and other applications via two‐stage activation

“…The XRD analysis gives an indication of the crystalline structures present in the sample, thus allowing identification of components such as cellulose; one of the main constituents of biomass samples. Cellulose crystallinity can be in the form of amorphous (diffraction lines at 2θ = 18°) or crystalline (diffraction lines at 2θ = 22° corresponding to the crystallographic plane (002) with JCPDS data 03–0289), whereas both hemicellulose and lignin are known to be amorphous in nature …”

“…The use of an activating agent does not have to be restricted to one step; once a char has been mixed with an activating agent and pyrolyzed, it can be activated further using a second activating agent. Ravichandran et al reported that a two‐step activation of the biomass could produce a higher adsorption AC with greater performance than a single activation AC. Compared to a one‐step activation, the two‐step activation was found to produce AC with ≤25% higher carbon yields.…”

“…In the literature, two‐step activation generally involves the biomass first being carbonized at temperature range of 300‐800 °C and then activated using an activating agent (KOH, H 3 PO 4 or ZnCl 2 ). For instance, Ravichandran et al reported that the biomass was pre‐carbonized at 300 °C, then activated with one of the three activating agents and then pyrolyzed at 700 °C, which resulted in AC of 548 m 2 g −1 . They focused primarily on the % AC yield.…”