Academic Publications
My Publications
2025
Alwis, DS.; Perera, PLRA; Rajapakse, C. S. K.
Calamondin Peel Waste-Derived Activated Carbon as a Biosorbent for Heavy Metal Removal from Aqueous Solutions Journal Article
In: Asian Journal of Chemistry , vol. 37 , iss. 7 (2025), pp. 1713 - 1719, 2025, ISSN: 0970-7077.
Abstract | Links | BibTeX | Tags: Activated carbon, Adsorption, Adsorptive removal, Drinking water, wastewater
@article{Alwis2025,
title = {Calamondin Peel Waste-Derived Activated Carbon as a Biosorbent for Heavy Metal Removal from Aqueous Solutions},
author = {DS. Alwis and PLRA Perera and C. S. K. Rajapakse},
url = {https://rajithperera.com/wp-content/uploads/2025/06/021-339201713-17192025.pdf},
doi = {10.14233/ajchem.2025.33920},
issn = {0970-7077},
year = {2025},
date = {2025-06-30},
urldate = {2025-06-30},
journal = { Asian Journal of Chemistry },
volume = {37 },
issue = {7 (2025)},
pages = {1713 - 1719},
abstract = {This research focused on utilizing agricultural waste, calamondin (Citrus madurensis) peel, to produce low-cost calamondin peel-based activated carbon (CPAC), initially for Pb(II) ion removal from simulated water. CPAC, prepared by carbonizing chemically treated peel waste at 400 ºC for 120 min, achieved 99% Pb(II) removal under optimized conditions: 5 ppm initial Pb(II) concentration, 0.03 g adsorbent dosage, 20 min shaking time at pH 7. Isotherm studies confirmed chemisorption, with a maximum adsorption capacity of 10.63 mg/g. Furthermore, CPAC demonstrated a removal efficiency of 31.01% to 49.29% for Cd, Cr, Cu, Mn and Zn in water samples collected from the Kelani river, Sri Lanka. These findings emphasize the viability of CPAC as a cost-effective, environmentally sustainable adsorbent for the remediation of heavy metal-laden water, thereby advancing sustainable waste management and environmental remediation.},
keywords = {Activated carbon, Adsorption, Adsorptive removal, Drinking water, wastewater},
pubstate = {published},
tppubtype = {article}
}
This research focused on utilizing agricultural waste, calamondin (Citrus madurensis) peel, to produce low-cost calamondin peel-based activated carbon (CPAC), initially for Pb(II) ion removal from simulated water. CPAC, prepared by carbonizing chemically treated peel waste at 400 ºC for 120 min, achieved 99% Pb(II) removal under optimized conditions: 5 ppm initial Pb(II) concentration, 0.03 g adsorbent dosage, 20 min shaking time at pH 7. Isotherm studies confirmed chemisorption, with a maximum adsorption capacity of 10.63 mg/g. Furthermore, CPAC demonstrated a removal efficiency of 31.01% to 49.29% for Cd, Cr, Cu, Mn and Zn in water samples collected from the Kelani river, Sri Lanka. These findings emphasize the viability of CPAC as a cost-effective, environmentally sustainable adsorbent for the remediation of heavy metal-laden water, thereby advancing sustainable waste management and environmental remediation.
Perera, WPRT; Chandrasoma, Indu; Perera, B; Rajapaksha, H; Sakunthala, KADD; Perera, PLRA; Liyanage, JA
Comparative analysis of drinking water quality in a CKDu endemic area versus a reference area in Sri Lanka: a topographic perspective Journal Article
In: International Journal of Environmental Quality -EQA, vol. 70, iss. 2025, pp. 28-35, 2025, ISSN: 2281-4485.
Abstract | Links | BibTeX | Tags: CKDu, Drinking water
@article{Perera2025b,
title = {Comparative analysis of drinking water quality in a CKDu endemic area versus a reference area in Sri Lanka: a topographic perspective },
author = {WPRT Perera and Indu Chandrasoma and B Perera and H Rajapaksha and KADD Sakunthala and PLRA Perera and JA Liyanage},
url = {https://eqa.unibo.it/article/view/21341
https://rajithperera.com/wp-content/uploads/2025/06/PERERA70202528-3521341.pdf},
doi = {10.6092/issn.2281-4485/21341 },
issn = {2281-4485},
year = {2025},
date = {2025-06-16},
journal = {International Journal of Environmental Quality -EQA},
volume = {70},
issue = {2025},
pages = {28-35},
abstract = {Chronic kidney disease of unknown cause (CKDu) is a serious health issue affecting Sri Lanka's farming communities. Continuous assessment of physico-chemical parameters and trace metals in drinking water sources is crucial for exploring the root cause of CKDu. This study investigates how geographical distribution affects trace metal and fluoride contamination in CKDu endemic Naminigama Grama Niladhari Division (GND) and Sulugune GND (reference area) in the same Divisional Secretariat (DS). Preliminary analysis indicates that trace elements, major elements, and fluoride concentrations of drinking water are within Sri Lanka’s water quality guidelines in both areas. However, long-term exposure to metals may generate risks. This study analysed well water samples from these sites for trace elements (cadmium, lead, chromium, arsenic, zinc, copper, iron) and major elements (sodium, potassium, aluminum) using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Additionally, fluoride, magnesium, and calcium levels were measured. Pb, Cd, As, and Cr were within permissible limits according to Sri Lankan water quality guidelines in both areas. However, aluminum levels exceeded limits in both areas. Statistical analysis showed significantly higher concentrations of Na, Mg, Ca, Zn, Cr, As, and Cd in Naminigama than the reference area. In Naminigama, agricultural fields are at higher elevations compared to residential areas, whereas opposite in Sulugune. The metal distribution variation may be due to the geographical condition of the reference area, where surface runoff attenuates agricultural waste, thereby reducing contamination of its drinking water sources. These findings suggest that topography plays a crucial role in water contamination, providing insights into improved water quality management.},
keywords = {CKDu, Drinking water},
pubstate = {published},
tppubtype = {article}
}
Chronic kidney disease of unknown cause (CKDu) is a serious health issue affecting Sri Lanka's farming communities. Continuous assessment of physico-chemical parameters and trace metals in drinking water sources is crucial for exploring the root cause of CKDu. This study investigates how geographical distribution affects trace metal and fluoride contamination in CKDu endemic Naminigama Grama Niladhari Division (GND) and Sulugune GND (reference area) in the same Divisional Secretariat (DS). Preliminary analysis indicates that trace elements, major elements, and fluoride concentrations of drinking water are within Sri Lanka’s water quality guidelines in both areas. However, long-term exposure to metals may generate risks. This study analysed well water samples from these sites for trace elements (cadmium, lead, chromium, arsenic, zinc, copper, iron) and major elements (sodium, potassium, aluminum) using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Additionally, fluoride, magnesium, and calcium levels were measured. Pb, Cd, As, and Cr were within permissible limits according to Sri Lankan water quality guidelines in both areas. However, aluminum levels exceeded limits in both areas. Statistical analysis showed significantly higher concentrations of Na, Mg, Ca, Zn, Cr, As, and Cd in Naminigama than the reference area. In Naminigama, agricultural fields are at higher elevations compared to residential areas, whereas opposite in Sulugune. The metal distribution variation may be due to the geographical condition of the reference area, where surface runoff attenuates agricultural waste, thereby reducing contamination of its drinking water sources. These findings suggest that topography plays a crucial role in water contamination, providing insights into improved water quality management.
2022
Ranasinghe, RAHB; Premaratne, WAPJ; Perera, PLRA; Perera, WPRT; Liyanage, JA
Risk assessment of toxic metal contamination in groundwater and paddy soil; A study in CKDu affected Maradankulama area in Anuradhapura, Sri Lanka Proceedings Article
In: International Conference on Applied and Pure Sciences, Faculty of Science, University of Kelaniya, Sri Lanka Faculty of Science, University of Kelaniya Sri Lanka, 2022.
Abstract | Links | BibTeX | Tags: CKDu, Drinking water, paddy soil, Toxic Metals
@inproceedings{ranasinghe2022risk,
title = {Risk assessment of toxic metal contamination in groundwater and paddy soil; A study in CKDu affected Maradankulama area in Anuradhapura, Sri Lanka},
author = {RAHB Ranasinghe and WAPJ Premaratne and PLRA Perera and WPRT Perera and JA Liyanage},
url = {https://www.researchgate.net/publication/364716756_Risk_assessment_of_toxic_metal_contamination_in_groundwater_and_paddy_soil_A_study_in_CKDu_affected_Maradankulama_area_in_Anuradhapura_Sri_Lanka},
year = {2022},
date = {2022-10-01},
urldate = {2022-01-01},
booktitle = {International Conference on Applied and Pure Sciences},
publisher = {Faculty of Science, University of Kelaniya Sri Lanka},
organization = {Faculty of Science, University of Kelaniya, Sri Lanka},
abstract = {Chronic Kidney Disease of Unknown Etiology (CKDu) has emerged as a serious public health concern in Sri Lanka. The North Central Region (NCR) has the highest CKDu prevalence in the country, and the disease is more prevalent among farming communities and people who rely on groundwater as their primary source of drinking water. Meanwhile, heavy metal/metalloids exposure and accumulation are recognized as the causative agent of many acute and chronic diseases in certain vulnerable human tissues, including the kidneys. This study assesses the level of contamination of heavy metals/metalloids in drinking water and agricultural soil in a CKDu endemic area in NCR, Sri Lanka. Fifteen groundwater samples collected from wells were analyzed for pH, EC, hardness, heavy metals, and anion concentration using potentiometric, conductometric, titrimetric, inductively coupled plasma mass spectrometric, and ion chromatographic methods, respectively. From six sampling sites in a paddy field, composite soil samples were collected from the surface, and two depths (30 cm and 60 cm). Soil samples were analyzed for pH, EC, organic matter, potassium, phosphate, and heavy metals using potentiometric, conductometric, titrimetric, flame photometric, colorimetric, and inductively coupled plasma mass spectrometric methods respectively. Accordingly, the mean pH of groundwater is 7.25 and this lies within the guideline values. Mean EC is 662.4 µS/cm and mean hardness is 287.0 mg CaCO3/L. Among fifteen samples, four and five water samples have exceeded the health guideline values for EC and hardness, respectively. Metal content varies in the following order, Cd < As < Cr < Cu < Co < Fe < Ni < Mn < Zn. Pb was not detected in any of the water samples and other metals were found in concentrations well below the standard guideline values. Only one sample and three samples exceeded the guideline value for fluoride and nitrite, respectively. Mean pH, EC, organic matter, potassium, and phosphate in paddy soil is 7.57, 101.8 µS/cm, 1.34%, 148.9 mg/kg, and 24.05 mg/kg respectively. Heavy metal content in soil varies in the following order, Cd < As < Pb < Co < Ni < Cu < Zn < Cr < Mn < Fe. Paddy soil from the very bottom showed the highest pH, Pb, Cd, As, Zn, Ni, Mn, Cr, and Fe content while the highest EC, organic matter and potassium content was detected in topsoil. EC, organic matter, and potassium content decreased with the depth of the soil, and the concentration of Pb, As, Zn, Mn, and Fe increased with the depth. This study reveals the dependence of some soil quality parameters on the depth of the soil profile. Monitoring the soil quality is important to minimize the possibility of heavy metal uptake by rice plants. Low heavy metal concentration in groundwater may not have an acute health effect on humans. But long-term chronic exposure to toxic heavy metals together with high EC, hardness, and fluoride would be a reason to trigger the prevalence of CKDu in Maradankulama area.},
keywords = {CKDu, Drinking water, paddy soil, Toxic Metals},
pubstate = {published},
tppubtype = {inproceedings}
}
Chronic Kidney Disease of Unknown Etiology (CKDu) has emerged as a serious public health concern in Sri Lanka. The North Central Region (NCR) has the highest CKDu prevalence in the country, and the disease is more prevalent among farming communities and people who rely on groundwater as their primary source of drinking water. Meanwhile, heavy metal/metalloids exposure and accumulation are recognized as the causative agent of many acute and chronic diseases in certain vulnerable human tissues, including the kidneys. This study assesses the level of contamination of heavy metals/metalloids in drinking water and agricultural soil in a CKDu endemic area in NCR, Sri Lanka. Fifteen groundwater samples collected from wells were analyzed for pH, EC, hardness, heavy metals, and anion concentration using potentiometric, conductometric, titrimetric, inductively coupled plasma mass spectrometric, and ion chromatographic methods, respectively. From six sampling sites in a paddy field, composite soil samples were collected from the surface, and two depths (30 cm and 60 cm). Soil samples were analyzed for pH, EC, organic matter, potassium, phosphate, and heavy metals using potentiometric, conductometric, titrimetric, flame photometric, colorimetric, and inductively coupled plasma mass spectrometric methods respectively. Accordingly, the mean pH of groundwater is 7.25 and this lies within the guideline values. Mean EC is 662.4 µS/cm and mean hardness is 287.0 mg CaCO3/L. Among fifteen samples, four and five water samples have exceeded the health guideline values for EC and hardness, respectively. Metal content varies in the following order, Cd < As < Cr < Cu < Co < Fe < Ni < Mn < Zn. Pb was not detected in any of the water samples and other metals were found in concentrations well below the standard guideline values. Only one sample and three samples exceeded the guideline value for fluoride and nitrite, respectively. Mean pH, EC, organic matter, potassium, and phosphate in paddy soil is 7.57, 101.8 µS/cm, 1.34%, 148.9 mg/kg, and 24.05 mg/kg respectively. Heavy metal content in soil varies in the following order, Cd < As < Pb < Co < Ni < Cu < Zn < Cr < Mn < Fe. Paddy soil from the very bottom showed the highest pH, Pb, Cd, As, Zn, Ni, Mn, Cr, and Fe content while the highest EC, organic matter and potassium content was detected in topsoil. EC, organic matter, and potassium content decreased with the depth of the soil, and the concentration of Pb, As, Zn, Mn, and Fe increased with the depth. This study reveals the dependence of some soil quality parameters on the depth of the soil profile. Monitoring the soil quality is important to minimize the possibility of heavy metal uptake by rice plants. Low heavy metal concentration in groundwater may not have an acute health effect on humans. But long-term chronic exposure to toxic heavy metals together with high EC, hardness, and fluoride would be a reason to trigger the prevalence of CKDu in Maradankulama area.