http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/74 2026-04-13T01:49:32Z 2026-04-13T01:49:32Z Kannan, N. Sirimanna, R.G.H.L. http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12425 2026-03-31T08:38:35Z 2026-01-01T00:00:00Z

Title: Incorporation of Paddy Husk Biochar and the Effectiveness of Colocasia esculenta Usage in Vertical Flow Constructed Wetlands for Treatment of Synthetic Wastewater Having “Rhodamine B” Authors: Kannan, N.; Sirimanna, R.G.H.L. Abstract: Incorporation of paddy husk biochar (PHBC 350) and Colocasia esculenta (C. esculenta) usage in vertical flow constructed wetlands (VFCWs) for treatment of synthetic wastewater mixed with rhodamine B (RhB) was the focus. To increase the removal efficiency of VFCW, pebbles (0.0125 m 3 ), sand (0.005 m 3 ), and PHBC 350 (0.0075 m 3 ) were used. Setups of VFCWs, S (sand) and SB (sand + biochar [30% v/v]), were established. DO, pH, TS, TDS, TSS, EC, color, turbidity, dye concentration, and RhB removal percentage were evaluated. The measured values of DO, EC, pH, TS, TDS, and TSS in SB were 6.03 mg/L, 1.72 mS/cm, 6.14, 1080 ppm, 860 ppm, and 220 ppm, respectively, in 10 days. Moreover, SB gave a statistical level of RhB removal of 81.5%. All in all, incorporation of biochar into VFCWs created new knowledge to advance the removal performance for wastewater mixed with organic pollutants by understanding its mechanistic dynamics.

2026-01-01T00:00:00Z Kannan, N, Srinanthakumar, N. Goonetilleke, A. McGree, J. Bandala, E.R. http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12424 2026-03-31T08:19:58Z 2026-01-01T00:00:00Z

Title: Biogenic carbon matrix with dual-mode adsorption capability: synthesis, characterization and mechanistic insights Authors: Kannan, N,; Srinanthakumar, N.; Goonetilleke, A.; McGree, J.; Bandala, E.R. Abstract: The transformation of biowaste into high-performance functional materials presents a promising strategy for sustainable environmental technologies. In this study, a novel biogenic carbon-based catalytic matrix (CBCM) was synthesized from prawn shell waste, integrating chitin-derived carbon and in-situ formed calcite to yield a hybrid material with distinctive structural and surface characteristics. Comprehensive characterization using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) revealed a composite architecture featuring both organic (Chitin) and inorganic (Calcite) crystalline domains, along with abundant surface oxygenated functional groups (O–H, C=O, CO–NH, and C–O). These structural attributes underpin the CBCM's dual-mode adsorption capability, enabling simultaneous and efficient uptake of both cationic (Malachite green) and anionic (Congo red) dyes. Kinetic and isotherm analyses highlighted the dominant roles of hydrogen bonding and π-π interactions, directly linked to the material's functional groups and porous surface morphology. Response surface modeling confirmed strong agreement between predicted and experimental adsorption capacities (R 2 = 0.978), underscoring the reliability of the structure-function correlation. This work demonstrates how rational design and valorization of marine biowaste can yield multifunctional materials, with the CBCM serving as a proof-of-concept platform for pollutant capture and broader environmental applications.

2026-01-01T00:00:00Z Kannan, N. Loveciya, S. Mayuresh, N. http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/12423 2026-03-31T08:43:55Z 2026-01-01T00:00:00Z

Title: Optimizing spray volumes of different spraying devices under controlled conditions for Abelmoschus esculentus (Okra) cultivation: A scientific exploration towards automation in spraying Authors: Kannan, N.; Loveciya, S.; Mayuresh, N. Abstract: Spraying is one of the important techniques to control pest infestation in vegetable fields. Improper pesticide application leads to chemical wastage and ineffective pest control, causing environmental pollution and ultimately reducing crop yield. To overcome these issues and to suggest suitable spraying techniques for particular growth stages of Abelmoschus esculentus (okra), a comprehensive field experiment was planned. Four different spraying techniques using hand-operated knapsack sprayers and power-operated knapsack sprayers: hand-operated knapsack low-volume (KL), hand-operated knapsack high-volume (KH), power-operated knapsack low-volume (PL), and power-operated knapsack high- volume (PH), were used with the incorporation of sensor technology to identify the pest and suitable pesticides. Major differences in droplet sizes among the treatments KL, KH, PL, and PH were 2.6±0.03 μm, 2.4±0.08 μm, 2.3±0.17 μm, and 2.1±0.05 μm, respectively. The results showed that treatment KL outperformed the other treatments at the seedling stage, and treatment KH was the optimal choice for the vegetative and fruit-bearing stages of okra for plant infestation and 90% wetting. The highest pest infestation was observed during the vegetative stage. Yield performance was induced by treatment KH, with the longest average pod length at 23.2±0.37 cm. Overall, with the advantages of plant interception, environmental loss, plant height, and pest infestation level, the KH more effectively supported all stages of okra development. The findings of this study emphasized a suitable spraying technique for each growth stage of okra with minimum environmental loss by incorporating sensors. The use of technology in basic agricultural activities is highly expected; thus, these findings will be useful for agricultural experts, farmers, and researchers in promoting eco-friendly and sustainable agriculture by minimizing chemical usage through precision pest management.

2026-01-01T00:00:00Z Kannan, N. Yanushiya, J. Shri Lasha, R. Bandala, E.R. http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/11057 2025-01-29T03:36:37Z 2025-01-01T00:00:00Z

Title: Understanding the interaction between selected microplastics and the toxic dye "Congo red" in water Authors: Kannan, N.; Yanushiya, J.; Shri Lasha, R.; Bandala, E.R. Abstract: This study thoroughly investigated the adsorption of Congo Red (CR) dye onto various microplastics (MPs), including high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), poly propylene (PP) and polyethylene terephthalate (PET). Initial adsorption capacities (qe) revealed that HDPE had the highest value (21.90 mg/g), followed by PVC (4.2 mg/g), LDPE (3.7 mg/g), PP (3.1 mg/g) and PET (2.8 mg/g). Based on these findings, HDPE and PVC were selected for detailed analysis. Adsorption experiments were conducted under controlled conditions: CR concentration of 100 mg/L, adsorbent dosage of 2 g/L, pH of 5, and temperature of 303 K. Isotherm studies indicated that HDPE followed the Freundlich model (R2 - 0.99), while PVC was best described by the Redlich-Peterson model (R2 - 0.97). Kinetic analysis showed that HDPE adhered to the Bangham model (reliable ((R2 = 0.9267, 0.950, 0.988, and 0.988) R2 values obtained for all the concentrations), highlighting pore-filling mechanisms. The conclusion, supported by FTIR analysis, indicates no significant changes in HDPE’s functional groups after the adsorption. In contrast, PVC followed a pseudo-second order kinetic model (reliable R2 values (0.999, 0.765, 0.956, 0.972) obtained for all the concentrations), suggesting chemisorption, confirmed by FTIR changes in the C–Cl bonds. The optimal pH for adsorption was 5 for HDPE and 4 for PVC. Both processes were exothermic with intraparticle and film diffusion identified as rate-limiting steps. Maximum adsorption capacities (qmax) were 110.1 mg/g for HDPE and 8.1 mg/g for PVC. Desorption experiments were conducted only for HDPE due to PVC’s lower adsorption. The highest desorption for HDPE occurred at pH 4 (5.7 mg/L) with an adsorbent dosage of 2 g/L. This study underscores the dual environmental threat posed by MPs, which not only adsorb organic pollutants like CR but also release them under certain conditions. While this research advances our understanding of MPs as pollutant carriers, future work should focus on their desorption behavior in complex, real-world environments. Further studies on other organic pollutants and microplastic types in real wastewater systems are also recommended.

2025-01-01T00:00:00Z