Preparation and Characterization of Nanoporous Activated Carbon Derived from Prawn Shell and Its Application for Removal of Heavy Metal Ions

Abstract

The aim of this study was to optimize the adsorption performance of activated carbon (AC), derived from the shell of Penaeus vannamei prawns, on heavy metal ions. Inexpensive, non-toxic, and renewable prawn shells were subjected to carbonization and, subsequently, KOH-activation to produce nanoporous K-Ac. Carbonized prawn shells (CPS) and nanoporous KOH-activated carbon (K-Ac) from prawn shells were prepared and characterized by FTIR, XRD, BET, SEM, and TEM. The results showed that as-produced K-Ac samples were a porous material with microporous and mesoporous structures and had a high specific surface area of 3160 m2/g, average pore size of about 10 nm, and large pore volume of 2.38 m3/g. Furthermore, batches of K-Ac samples were employed for testing the adsorption behavior of Cd2+ in solution. The effects of pH value, initial concentration, and adsorption time on Cd2+ were systematically investigated. Kinetics and isotherm model analysis of the adsorption of Cd2+ on K-Ac showed that experimental data were not only consistent with the Langmuir adsorption isotherm, but also well-described by the quasi-first-order model. Finally, the adsorption behaviors of as-prepared K-Ac were also tested in a ternary mixture of heavy metal ions Cu2+, Cr6+, and Cd2+, and the total adsorption amount of 560 mg/g was obtained.

Efficient Adsorption of Lead (II) from Aqueous Phase Solutions Using Polypyrrole-Based Activated Carbon

“…In this figure, it can be seen that the Pb 2+ adsorption was rapid in the first stage of adsorption, then slowly increased with time, becoming almost constant after 120 min. This phenomenon can be attributed to the high availability of vacant adsorption sites in the first stage of adsorption, followed by an increase in repulsive forces due to the presence of the adsorbed ions, making the remaining sites more difficult to access [37,41]. It was observed that the ion removal percentage was slightly reduced with an increase in initial concentration (Figure 4 and Figure 5).…”

“…Pseudo-first-order Equation (3) assumes that the adsorption rate is based on the adsorption capacity. The pseudo-second-order model, Equation (4), is based on the assumption that the adsorption is controlled by the chemisorption mechanism, involving valency forces through electron sharing or transfer between the adsorbent and adsorbate [36,37]. log(qe−qt)=logfalse(qefalse)−k1t2.303 tqt=1k2qe2+tqe where q t and q e (mg/g) are the amount of Pb 2+ adsorbed per mass of adsorbent (g) at time t (min) and at equilibrium, respectively, and k 1 (1/min) and k 2 (mg/(g∙min)) are the rate constants of the pseudo-first-order and pseudo-second-order models, respectively.…”

Adsorption of Azo Dye Methyl Orange from Aqueous Solutions Using Alkali-Activated Polypyrrole-Based Graphene Oxide

“…The PFO model (Equation (11)) assumes the adsorption rate based on the adsorption capacity. The PSO (Equation (12)) model is based on the assumption that the adsorption is controlled by the chemisorption mechanism, involving valency forces through electron sharing or transfer between the adsorbent and the adsorbate [38,40]. For the intra-particle diffusion model (Equation (14)), the plot of q t versus t 0.5 is assumed to be linear, passing through the origin; otherwise, some other mechanism may be involved.…”

Batch and continuous fixed bed adsorption of heavy metals removal using activated charcoal from neem (Azadirachta indica) leaf powder

“…Currently, investigations are ongoing for preparation of charcoal using low cost materials, natural materials, agricultural waste, etc. 10 . Regarding adsorption process, it is performed by batch, up-flow or down-flow continuous fixed bed, continuous fluidized bed, continuous moving bed and oscillated (pulsed) bed, in which batch and up-flow continuous fixed bed adsorption investigations are more feasible due to easy and cheap technique and can removed most of contaminations 11 .…”