High surface area activated carbon from a pineapple ( ananas comosus ) crown via microwave-ZnCl 2 activation for crystal violet and methylene blue dye removal: adsorption optimization and mechanism

• Published in: International journal of phytoremediation Vol. 26; no. 3; pp. 324 - 338
• Main Authors: Hapiz, Ahmad, Jawad, Ali H, Wilson, Lee D, ALOthman, Zeid A
• Format: Journal Article
• Language: English
• Published: United States 23.02.2024
• Subjects: Adsorption; Ananas; Biodegradation, Environmental; Charcoal - chemistry; Coloring Agents - chemistry; Gentian Violet; Hydrogen-Ion Concentration; Kinetics; Methylene Blue - analysis; Methylene Blue - chemistry; Microwaves; Water Pollutants, Chemical - analysis; methylene blue; pineapple crown; Box-Behnken design; crystal violet; Activated carbon; microwave
• ISSN: 1522-6514; 1549-7879
• DOI: 10.1080/15226514.2023.2241912

In this investigation, microwave irradiation assisted by ZnCl was used to transform pineapple crown (PN) waste into mesoporous activated carbon (PNAC). Complementary techniques were employed to examine the physicochemical characteristics of PNAC, including BET, FTIR, SEM-EDX, XRD, and pH at the point-of-zero-charge (pH ). PNAC is mesoporous adsorbent with a surface area of 1070 m /g. The statistical optimization for the adsorption process of two model cationic dyes (methylene blue: MB and, crystal violet: CV) was conducted using the response surface methodology-Box-Behnken design (RSM-BBD). The parameters include solution pH (4-10), contact time (2-12) min, and PNAC dosage (0.02-0.1 g/100 mL). The Freundlich and Langmuir models adequately described the dye adsorption isotherm results for the MB and CV systems, whereas the pseudo-second order kinetic model accounted for the time dependent adsorption results. The maximum adsorption capacity ( ) for PNAC with the two tested dyes are listed: 263.9 mg/g for CV and 274.8 mg/g for MB. The unique adsorption mechanism of MB and CV dyes by PNAC implicates multiple contributions to the adsorption process such as pore filling, electrostatic forces, H-bonding, and π-π interactions. This study illustrates the possibility of transforming PN into activated carbon (PNAC) with the potential to remove two cationic dyes from aqueous media.