Hydrothermally Treated Banana Empty Fruit Bunch Fiber Activated Carbon for Pb(II) and Zn(II) Removal

Abstract

Activated carbon was produced by chemical activation of hydrothermally carbonized (HTC) banana empty fruit bunch (BEFB), using phosphoric acid (H3PO4) as the activating agent. The activation process was optimized using a Box-Behnken factorial design (BBD), with an outcome of 17 different experiments under the predefined conditions. Three different parameters (activation temperature (x1), activation time (x2), and the concentration of activating acid (x3)) were analyzed with respect to their influence on maximum adsorption percentage for divalent cations, Pb(II) (Y1) and Zn(II) (Y2), and carbon yield (Y3). All process parameters had strong positive effects on adsorption capacity up to a certain limit. The specific surface area of the hydrochar (HTC) was enhanced substantially after the activation process. Scanning electron microscopy (SEM) revealed that the morphology of the BEFB-based char changed noticeably after the acid impregnation and activation process. The Langmuir maximum monolayer adsorption capacity for Pb (II) and Zn (II) cations was 74.62 mg/g and 77.51 mg/g, respectively. Equilibrium isotherm data were in agreement with the Langmuir model. Thermodynamic characterization revealed that the equilibrium system was endothermic and spontaneous.

The Effects of Pre-treatments and Low-temperature Pyrolysis on Surface Properties of Biochar from Sunflower Straw as Adsorption Material

“…Recently, cheap and environmentally friendly adsorbents using agricultural wastes have become a popular research topic (Njoku et al 2014;Yahya et al 2015;Adebisi et al 2016;Narimane et al 2016). In general, activated carbon adsorbent is prepared through carbonization and then activated with two steps, with the activation temperature being higher than the carbonization temperature (> 500 °C) (Liou 2010;Dinesh et al 2014;Eda and Canan 2015).…”

Adsorption Studies of Volatile Organic Compound (Naphthalene) from Aqueous Effluents: Chemical Activation Process Using Weak Lewis Acid, Equilibrium Kinetics and Isotherm Modelling

“…As the concentration range increased, both the experimental and calculated q e values increased. Similarly, the boundary layer effect, C i , observed for the adsorption onto DSP and CDSP also showed an increasing trend ( Table 2 and Table 3 ) with the concentration [ 40 , 41 ].…”

“…The linear plots obtained for the intraparticle diffusion process did not cross the origin ( Figure 4 ). This reflected that the rate-controlling steps for the adsorption process were not only controlled by pore diffusion, some other mechanisms of dipole-dipole interactions and hydrogen bonding took place during the adsorption process [ 10 , 40 , 41 ]. From the linear plots ( Figure 2 , Figure 3 and Figure 4 ), the pseudo-first and second and intraparticle diffusion plot variables and constants are estimated and summarized in the following Table 2 and Table 3 .…”

“…Over the DSP sample, all the concentration ranges (12.5–75 ppb) under investigation followed the pseudo-second order model ( Table 2 ). This implied, over the DSP sample, C 10 H 8 adsorption also proceeded via the chemical adsorption process [ 10 , 40 , 41 ]. As the concentration range increased, both the experimental and calculated q e values increased.…”

Equilibrium Isotherm, Kinetic, and Thermodynamic Studies of Divalent Cation Adsorption onto Calamus gracilis Sawdust-Based Activated Carbon

“…The high BET surface area and pore volumes of the RSAC were greatly enhanced by the two steps (hydrothermal treatment and chemical activation with phosphoric acid) undertaken in this preparation process. The H3PO4 acid further initiated the dehydration process and carried out the depolymerization reaction successfully, attacking the basal structural sheets inside the hydrochar matrix (Adebisi et al 2016, Fernandez et al 2015. Thus, the resultant activated carbon showed enhanced pore volume and surface area.…”