TY  - MANSCPT
AU  - Prabu A/L Rajandran,
TI  - Adsorptive removal of carbazole from industrial wastewater using β-cyclodextrin-functionalized activated rice husk biochar
SN  - THE0009501 (Local)
PY  - 2026///
CY  - Kuantan, Pahang
PB  - UMPSA
KW  - Faculty of Chemical and Process Engineering Technology
KW  - Dissertations
KW  - Universities and colleges
KW  - Theses
N1  - Faculty of Chemical and Process Engineering Technology; Thesis (Master of Science) -- Universiti Malaysia Pahang Al Sultan Abdullah - 2026; Include bibliographical reference
N2  - To assess the potential of β-cyclodextrin-functionalized activated rice husk biochar (CDARHB) for carbazole removal, the adsorbent was first synthesized by activating rice husk biochar with hydrochloric acid, and was then functionalized with β-cyclodextrin. The resulting CD-ARHB was subsequently characterized to confirm the successful incorporation of β-cyclodextrin. Batch adsorption experiments were then conducted to investigate the mechanisms governing carbazole adsorption onto CD-ARHB, followed by continuous adsorption studies to evaluate its practical performance. Finally, desorption experiments were carried out to examine the adsorbent’s regeneration potential and reusability. Characterization analyses verified the successful attachment of cyclodextrin onto the biochar, as evidenced by scanning electron microscopy images showing the deposition of white fragments and by functional group, thermal, and elemental analyses revealing characteristic cyclodextrin features. Isotherm analysis from batch experiments indicated that the Freundlich model provided the best fit (Freundlich isotherm constant = 4.87 L mg-1 and Freundlich heterogeneity constant = 5.08), suggesting multilayer adsorption on a heterogeneous surface. Kinetic analysis further showed that the adsorption process was well described by the pseudo-second-order (PSO) model (PSO rate constant = 0.0044 g mg-1 min-1 and PSO model predicted equilibrium adsorption capacity = 11.9617 mg g-1) and the intraparticle diffusion (IPD) model, with the latter exhibiting a multi-linear pattern (Segment 1: IPD rate constant (kIPD) = 0.537 mg g-1 min0.5 and thickness of the boundary layer (c) = 3.9191 mg g-1; Segment 2: kIPD = 0.0478 mg g-1 min0.5 and c = 10.465 mg g-1), implying that film diffusion, intraparticle diffusion, and chemisorption collectively governed the process. Continuous adsorption experiments using synthetic wastewater demonstrated the effectiveness of CD-ARHB for carbazole removal, achieving a maximum adsorption capacity of 23.20 mg g-1 under onefactor- at-a-time conditions at 20 mg L-1 carbazole, 2.5 g of CD-ARHB, and a flow rate of 2.0 mL min-1. Further optimization using central composite design revealed that a quadratic model best described the system, with satisfactory statistical performance (coefficient of variation of 4.07, coefficient of determination (R²) of 0.9705, adjusted R² of 0.9439, predicted R² of 0.8437, and adequate precision of 18.523). The model predicted optimal conditions at 18 mg L-1 carbazole, a flow rate of 1.9 mL min-1, and 2.7 g of CDARHB, corresponding to a maximum adsorption capacity of 25.27 mg g-1, which was experimentally validated at 26.31 mg g-1, showing only a 4.11% deviation and confirming the model’s robustness. When applied to actual industrial wastewater, the optimized conditions yielded a carbazole adsorption capacity of 5.15 mg g-1, underscoring the material’s potential for real-world applications despite the complexity of the wastewater matrix. Desorption studies further demonstrated the stability and reusability of CDARHB, which retained more than 50% of its adsorption capacity after three cycles when regenerated with dichloromethane. Overall, these findings highlight CD-ARHB as a promising, cost-effective, and sustainable adsorbent for carbazole removal from industrial wastewater, while also indicating scope for further improvement through material modification and process optimization
ER  -