Rajith Perera

@inproceedings{Perera2024b,

title = {Graphene Oxide Coated Sand Composites as Molecular Sieves to Mitigate Water Contaminants},

author = {WPRT Perera and NMN Ruwanthi and PLRA Perera and AVAP Vitharama and JA Liyanage and AR Kumarasinghe},

url = {https://www.researchgate.net/publication/377242262_Graphene_Oxide_Coated_Sand_Composites_as_Molecular_Sieves_to_Mitigate_Water_Contaminants},

year  = {2024},

date = {2024-01-05},

volume = {28},

number = {166},

pages = {88},

publisher = {International Forestry and Environment Symposium},

address = {Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Sri Lanka},

organization = {University of Sri Jayewardenepura},

keywords = {Adsorption, Graphene oxide, MCPA, Sand},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Perera2023b,

title = {Development of sand/graphene composite and its application for MCPA pesticide adsorption from water},

author = {WPRT Perera and NMN Ruwanthi and PLRA Perera and Amila Kannangara and WAPJ Premaratne and JA Liyanage and AR Kumarasinghe},

url = {https://www.researchgate.net/publication/374847773_Development_of_sandgraphene_composite_and_its_application_for_MCPA_pesticide_adsorption_from_water},

year  = {2023},

date = {2023-10-13},

booktitle = {International Conference on Applied and Pure Sciences (ICAPS)},

number = {49},

pages = {113},

publisher = {University of Kelaniya, Sri Lanka},

abstract = {This research endeavours to synthesize a novel adsorbent, sand/graphene oxide composite (M-GO/S), achieved through the iterative deposition of graphene oxide layers on river sand employing a thermal annealing process. Scanning electron microscopic (SEM) and Fourier-transform infrared spectroscopy (FT-IR) characterization studies revealed the presence of a non-uniform graphene oxide coating on the surface of the sand and the incorporation of oxygenated functional moieties within the structure. Comparative evaluations show the heightened adsorption capacity of this new composite entity with alternative sorbent materials, such as activated carbon, graphene oxide, and sand to adsorb neutral 2-methyl-4-chlorophenoxyacetic acid (MCPA) pesticide molecule. To analyse the MCPA adsorption parameters, High-performance liquid chromatography (HPLC)was used (Solvent mixture-Acetonitrile: Distilled water (1:1); Flow rate-1.5µLmin-1; Wave length-275nm). The retention time for the MCPA was reported as 1.538s. The optimization studies and adsorption modelling were carried out, focusing on the adsorption of MCPA onto the M-GO/S. Accordingly, the optimum concentration, dosage, and contact time were 75 mg/L, 0.05 g, and 105 minutes respectively, at neutral pH values. The investigation of adsorption equilibrium isotherms has highlighted the Freundlich model's (multilayer adsorption) superior explanatory capacity in characterizing the adsorption phenomenon. Concurrently, the analysis of adsorption kinetics has demonstrated a favourable fit with the pseudo-second-order model (with a correlation coefficient denoted as 0.9754), implying a prevailing chemical sorption mechanism underlying the adsorption process. Although MCPA possesses either neutral or negatively charged (upon dissolution) surfaces, the M-GO/S composite exhibits significant adsorption capability towards MCPA. Consequently, the synthesized composite emerges as a viable candidate for effectively mitigating MCPA pesticide contamination from water.},

keywords = {Adsorption, Graphene oxide, Kinetic, Pesticide, Sand},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{wprt2023core,

title = {Core-Shell Adsorbent Granules Fabricated from Sand/Graphene Oxide Nanocomposite for Adsorptive Removal of Pb (II)},

author = {WPRT Perera and PLRA Perera and AR Kumarasinghe and JA Liyanage},

url = {https://www.researchgate.net/publication/367653776_Environmental_Engineering_and_Green_Technology_Core-Shell_Adsorbent_Granules_Fabricated_from_SandGraphene_Oxide_Nano-Composite_for_Adsorptive_Removal_of_Pb_II},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

booktitle = {International Forestry and Environment Symposium},

volume = {27},

number = {55},

pages = {129},

address = {Sri Lanka},

organization = {University of Sri Jayewardenepura},

series = {Environmental Engineering and Green Technology},

abstract = {Core-shell absorbent granules are produced by coating commercial sand gravels with graphite oxide (few-layer oxidized graphene sheets). Graphite oxide (GO) is synthesized chemically from vein graphite, a rare form of high-purity natural graphite. Repeated coatings of graphite oxide on the sand followed by low temperature (120 0 C) thermal pyrolysis produce core-shell granules with a hierarchical structure in which sand gravels are covered by graphite oxide layers. The intention of this study is to assess the feasibility of the mitigation of Pb (II) from the water by sand/graphene oxide nano-composite and study the dynamic behavior of the adsorption mechanism using mathematical modeling. Individual materials and the resulting nanocomposite are characterized using a range of spectroscopic (FTIR, XRD, XPS) and microscopic (SEM/EDXA) techniques to elucidate the process of transforming individual materials into nanocomposite and to assess its suitability for removing Pb (II) from water. Stable sand/graphite oxide nanocomposites were obtained upon five times coating of GO on the sand surface and characterization shows that functionalized and a porous coating developed on the sand. The Pb (II) removal efficiency increases from high-acidic to neutral pH and decreases after basic (pH-8). The adsorption process takes 150 minutes to reach the equilibrium. After 150 minutes, the Pb (II) ion adsorption rate was constant. The maximum dosage of the nanocomposite needed to reach the equilibrium was 0.06g. Under the optimum conditions, 96.3% of Pb (II) removal efficiency was recorded from simulated Pb (II) containing water. According to the mathematical modeling, adsorption follows the Langmuir isotherm and fits well with the pseudo 2 nd order kinetics model, indicating a homogeneous adsorption process via a monolayer process and Pb adsorbed onto the surface of the sand/GO nanocomposite by chemisorption. Sand/GO nanocomposite is an excellent candidate for removing Pb (II) from contaminated water.},

keywords = {Adsorption, Graphene oxide, Sand, Water treatment},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{perera2022adsorptive,

title = {Adsorptive removal of Cd (II) from aqueous solutions by sand/graphite oxide nano-composites: characterization, isotherm, and kinetic studies},

author = {WPRT Perera and PLRA Perera and AR Kumarasingha and JA Liyanage},

url = {https://www.researchgate.net/publication/367161154_Adsorptive_removal_of_Cd_II_from_aqueous_solutions_by_sandgraphite_oxide_nano-composites_characterization_isotherm_and_kinetic_studies},

year  = {2022},

date = {2022-12-01},

urldate = {2022-12-01},

booktitle = {International Postgraduate Research Conference (IPRC) },

volume = {2022},

pages = {93},

publisher = {Faculty of Graduate Studies, University of Kelaniya Sri Lanka},

abstract = {Core-shell absorbent granules were developed by coating commercial sand gravels with graphite oxide (few-layer oxidized graphene sheets). Graphite oxide (GO) is synthesized chemically from vein graphite, a rare form of high-purity natural graphite (NVG). Modified Hammer's method was followed in order to synthesize graphene oxide from the NVG. Repeated coatings of graphite oxide on the sand followed by low temperature (120 0 C) thermal pyrolysis resulted in core-shell granules with a hierarchical structure in which sand gravels are covered by graphite oxide layers. Five times GO coated water stable sand/graphite oxide nano-composites (M-S/GO) were developed for further adsorption studies. The adsorption performance and mechanism of Cd (II) removal were investigated and FT-IR, SEM, EDX, and XPS were used to characterize the (M-S/GO) as spectroscopic and microscopic characterization methods. Optimization studies were carried out to find the effective pH of the media, dosage, initial concentration of Cd (II), and contact time that reached the equilibrium. Apart from that, the models of kinetics (pseudo-first order and pseudo-second order), and isotherms (Langmuir and Freundlich) were introduced. Characterization findings indicated that un-uniform graphene oxide coatings had been constructed on the sand surface and the surface of the nano-composite comprised of oxygen-based functional groups. Under optimum conditions (0.08 g/L of dosage, 65 mg/L initial Cd concentration, 120 min of contact time), the M-S/GO removed 93.8% of Cd (II) from simulated water at pH 8.0 (30 ± 2 ℃) and the process reached equilibrium after 120 minutes. The adsorption capacity of Cd (II) was augmented when increasing the pH of the medium up to pH=8, and then it tended to reduce. Further, the experimental data have been fitted with the Langmuir isotherm model indicating that monolayer adsorption of Cd (II) occurs on the surface of M-S/GO. Apart from that, M-S/GO had a maximum adsorption capacity (mg/g) (Qmax) value for Cd (II) adsorption (16.12 mg/g) than sand and GO, the equilibrium parameter (RL) value in this study was 0.071, which indicates that Cd (II) adsorption onto the surface of the M-S/GO is favorable. The experiment kinetic data were best fitted to a pseudo-second-order kinetic model indicating that Cd (II) has adsorbed onto the surface of the M-S/GO by a chemical sorption mechanism. These findings imply that M-S/GO could be used as an effective adsorbent for removing Cd (II) from contaminated water sources. More research is required to determine the reusability of M-S/GO in the adsorptive removal process.},

keywords = {Adsorption, Cadmium, Graphene oxide, Isotherm, Kinetic, Sand},

pubstate = {published},

tppubtype = {inproceedings}

}