Sustainable Dye Adsorption Using Novel Activated Carbon Prepared from Passion Fruit (Passiflora edulis) Leaf: Mechanism and Cost Analysis

With the aim of achieving circular economy, green and sustainable development, and efficient wastewater treatment, two biomass-based adsorbents were developed from passion fruit leaf through the carbonization (Raw-PFL) process and chemical activation using the NaOH (NaOH-PFL) process. The effects of operating parameters, namely, concentration of dye, pH, dosage of adsorbent, and retention time, were examined for anionic AB113 and cationic MB dye removal. Characterization results of FTIR analysis revealed that the adsorbents were enriched with various surface functional groups. Also, with NaOH activation, the Langmuir and BET surface areas were observed to be increased from 613.8 and 501.6 to 1782.4 and 1332.3 m(2)/g, respectively, with a more porous structure as indicated in SEM images, which is comparable to commercial ACs. AB113 and MB dyes were adsorbed onto Raw-PFL and NaOH-PFL in a chemisorption-based process according to a pseudo-second order with the highest R-2 value. A notable enhancement in Langmuir monolayer adsorption capacity was spotted after NaOH activation, from 107.5 to 227.3 mg/g for AB113 and from 31.3 to 666.7 mg/g for MB dye. Based on the cost analysis, NaOH-modified PFL is the more feasible adsorbent for removing pollutants from aqueous solutions, with the costs required for removing 1 kg of AB113 dye and MB dye being 7.2 and 91.0% lower compared to Raw-PFL and also lower than those of the commercial ACs, which range from 78.9 to 98.2% for the AB113 dye and 89.9 to 97.2% for the MB dye. Hence, passion fruit leaf is demonstrated to be an attractive precursor in developing adsorbents for removing contaminants from water bodies due to its tailored characteristics and performance.

Automated summary

In this study, two biomass-based adsorbents were developed from passion fruit leaf for efficient wastewater treatment. The NaOH-activated adsorbent showed increased surface area and improved adsorption capacity compared to the raw adsorbent. Cost analysis revealed that the NaOH-modified adsorbent was more cost-effective for pollutant removal from aqueous solutions.