Publications by authors named "Sameera R Gunatilake"

Per- and poly-fluoroalkyl substances (PFAS) can cause deleterious effects at low concentrations (70 ng/L). Their remediation is challenging. Aqueous μg/L levels of PFOS, PFOS, PFOSA, PFBS, GenX, PFHxS, PFPeA, PFHxA, and PFHpA (abbreviations defined in Table 1) multi-component adsorption (pH dependence, kinetics, isotherms, fixed-bed adsorption, regeneration, complex matrix) was studied on commercial Douglas fir biochar (BC) and its FeO-containing BC.

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Biochar has widely been utilized as an agricultural soil amendment owing to its enhanced surface properties and cost-effectiveness. In the present work, the influence of tea waste biochar (TWBC) upon acid modification on Allium cepa L. (red onion) growth has been studied.

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Remediation of steroidal estrogens from aqueous ecosystems is of prevailing concern due to their potential impact on organisms even at trace concentrations. Biochar (BC) is capable of estrogen removal due to its rich porosity and surface functionality. The presented review emphasizes on the adsorption mechanisms, isotherms, kinetics, ionic strength and the effect of matrix components associated with the removal of steroidal estrogens.

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Digestion of biomass derived carbonaceous materials such as biochar (BC) can be challenging due to their high chemical recalcitrance and vast variations in composition. Reports on the development of specific sample digestion methods for such materials remain inadequate and thus require considerable attention. Nine different carbonaceous materials; slow-pyrolyzed tea-waste and king coconut BC produced at 300 °C, 500 °C and 700 °C, sludge waste BC produced at 700 °C, wet fast-pyrolyzed Douglas-Fir BC and steam activated coconut shell BC have been tested to evaluate a relatively fast and convenient open-vessel digestion method using seven digestion reagents including nitric acid (NA), fuming nitric acid (FNA), sulfuric acid (SA), NA/SA, FNA/SA, NA/HO and SA/HO mixtures.

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Magnetic FeO/Douglas fir biochar composites (MBC) were prepared with a 29.2% wt. FeO loading and used to treat As(III)-contaminated water.

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Tea-waste is an abundant feedstock for producing biochar (BC) which is considered to be a cost effective carbonaceous adsorbent useful for water remediation and soil amendment purposes. In the present study, tea-waste BC (TWBC) produced at three different temperatures were subjected to nitric, sulfuric and hydrochloric acid modifications (abbreviated as NM, SM and HM respectively). Characteristics of the raw and modified BC such as ultimate and proximate analyses, surface morphology, surface acidity and functionality, point of zero charge, cation exchange capacity (CEC) and thermal stability were compared to evaluate the influence of pyrolysis temperature and of modifications incorporated.

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The remediation of volatile organic compounds (VOCs) from aqueous solution using Municipal solid waste biochar (MSW-BC) has been evaluated. Municipal solid waste was pyrolyzed in an onsite pyrolyzer around 450 C with a holding time of 30 min for the production of biochar (BC). Physiochemical properties of BC were assessed based on X-Ray Fluorescence (XRF) and Fourier transform infra-red (FTIR) analysis.

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Utilization of biochar (BC) as a low cost adsorbent for water remediation has gained an immense research interest due to their surface functionality and porosity. Although many reports on the BC based sorptive removal of Sulfonamides (SA) and Tetracyclines (TC) are available in literature, a deep insight into sorption mechanisms is yet to be reviewed. Objective of this review is to fill the research gap of a methodological understanding of sorption mechanisms and characteristics which is essential to develop efficient methods for contaminant removal.

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An improved method for trace level quantification of dicyandiamide in stream water has been developed. This method includes sample pretreatment using solid phase extraction. The extraction procedure (including loading, washing, and eluting) used a flow rate of 1.

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We present an improved method for trace level quantification of five estrogens including estriol, estrone, 17alpha-estradiol, 17beta-estradiol, and 17alpha-ethinylestradiol in wastewaters. Our method includes sample preparation using SPE followed by a Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) cleanup step, a derivatization, and LC/MS/MS determination. Sample extraction was carried out using Oasis HLB cartridges and a dispersive solid-phase cleanup pack containing MgSO4 and primary-secondary amine and C18 sorbents.

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