Improved heterocyclic aromatic hydrocarbon compound adsorption using functionalised rice husk biochar

• Published in: Bioresource technology reports 2024-02, Vol.25, p.101704, Article 101704
• Main Authors: Azman, Nur Azzyyati, Fuzi, Siti Fatimah Zaharah Mohd, Manas, Nor Hasmaliana Abdul, Azelee, Nur Izyan Wan, Masngut, Nasratun
• Format: Article
• Language: English
• Subjects: Adsorption; Biochar; Carbazole; Heterocyclic aromatic hydrocarbon; Rice husk; Starch derivative
• ISSN: 2589-014X; 2589-014X
• DOI: 10.1016/j.biteb.2023.101704

Carbazole (CBZ) is a hazardous heterocyclic aromatic hydrocarbon (HAH) that pollutes water bodies, and the treatment remains a challenge due to its high persistence in the environment. This study chemically modified rice husk biochar (RHB) with starch derivative (DS) to develop an effective adsorbent. Thus, functionalised RHB with starch derivative (RHBDS) was synthesised to remove CBZ from synthetic wastewater. Based on a Box-Behnken design, the DS functionalisation optimisation was successfully performed. The parameters, including RHB mass of (5–10) g, DS concentration of (1–5)% w/v, and sonication period of (1–5) min, were analysed using Design Expert. These parameters were then utilised to investigate the optimal conditions (removal rate response and adsorption capacity) for the adsorbent. The removal rate and the adsorption capacity ranged from 83.85 to 98.94 % and 335.41 to 395.76 mg/g, respectively. Consequently, the RHB mass of 6.50 g, DS concentration of 1 % w/v, and sonication period of 5 min within the experimental domain exhibited the best conditions with desirability of 1.0. The 92.67 % removal rate and adsorption capacity of 370.59 mg/g were also obtained under optimal conditions. Compared to RHB, RHBDS demonstrated four times the adsorption capacity for the CBZ removal from synthetic water, which were 23.03 mg/g and 98.01 mg/g, respectively. Therefore, the RHBDS compound could be a promising adsorbent in removing CBZ from wastewater. [Display omitted] •Adsorption is preferred for pollutant remediation due to its simple application.•The adsorption capacity was four times greater in functionalized rice husk biochar.•SEM images reveal that acid treatment increases porosity on the surface of biochar.