Search

Microplastic pollution (MP) in marine environments around the globe is severe and insufficient precautions have yet to be taken for its prevention. The focus of this study was on quantifying MPs from beach sediment and seawater samples and identifying their distributions and types along the western coast of Sri Lanka from the Kelani River estuary to the Mahaoya estuary. Nine sites along this 42 km stretch were selected, and random sampling was employed to collect a minimum of eight sediment samples from each site between October and December 2021. Water samples were also collected, parallel to the sediments, from the ocean surface. FTIR analysis revealed that most of the MPs found were polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), and phenol formaldehyde resin. The mean abundance of MPs varied from 2.0 ± 0.6 items/L to 161.0 ± 15.7 items/L in water samples and from 3.0 ± 0.3 items/m2 to 656.0 ± 34.5 items/m2 in sediment samples. The MPs found were identified in different shapes as fragments (80.2%), pellets (14.9%), fibers (2.7%), and foams (2.5%). Analysis revealed that the beach sediments were contaminated with PS, phenol formaldehyde resin, PET, PP, and PE, while the surface seawater was dominated by phenol formaldehyde resin, PS, PP, and PE. [ABSTRACT FROM AUTHOR]

Biochar is widely utilized in low-cost water treatment. However, chemicals used in most of the recorded activation techniques are corrosive, may cause secondary pollution, and not accessible by rural communities, reducing their value of being cost-effective. In this study, Trema orientalis wood biochar (WB) was successfully activated with natural coconut vinegar employing a facile technique to produce a green adsorbent for efficient aqueous methylene blue (MB) removal. Batch studies showed a three-fold higher MB adsorption capacity of coconut vinegar treated wood biochar (CVWB) compared to WB. Percentage removal ranged between 98-79% at lower dye concentrations (50-100 mg/L) and 79-48% at higher dye concentrations (100-300 mg/L). Isotherm data best fitted to the Freundlich model. Kinetic data fitted to both pseudo second order and intraparticle diffusion models, suggesting that the adsorption was governed by a pore filling mechanism with predominant electrostatic attractions, and the reaction rate was diffusion controlled. FTIR, XPS, and water contact angle measurements confirmed increased surface oxygenated groups of CVWB. XPS showed a three-fold increase in O/C atomic ratio. BET and AFM studies gave evidence to the increased porosity. Therefore, the enhanced MB adsorption capacity of CVWB was attributed to both the increased surface oxygenated functional groups and porosity. [ABSTRACT FROM AUTHOR]

Recent investigations have revealed the harmful health effects of elevated calcium levels in drinking water. Chemically activated biochar is the most popular option for low-cost cation adsorption. However, most of these chemicals are hardly available for rural communities, corrosive, and difficult to handle by unskilled personnel. This study aimed to determine the ability of natural coconut vinegar, a common mild acid, to activate Trema orientalis wood biochar pyrolyzed at 300°C (BC) as a facile, safe, and low-cost approach for aqueous calcium ion (Ca2+) removal. Column tests showed a two-fold increase of Ca2+ adsorption capacity and a ten-fold increase of Ca2+ retaining capacity of BC after activation with vinegar. The isotherm results were well correlated with the Langmuir model. The maximum Langmuir adsorption of the activated biochar (BC-A) was 9.96 mg/g. Ca2+ amount was determined using flame photometry. EDX analysis showed that the O/C ratio of BC increased from 0.07 to 0.13 after activation. FTIR and wettability studies showed increased oxygenated functional groups on the BC-A surface. The authors suggest a possible acid-catalyzed hydration of the C-O-C bridges of the biochar, introducing new hydroxyl/carbonyl/ester/carboxylic/lactone groups to the biochar surface due to the vinegar activation, enhancing Ca2+ adsorption through chemisorption. [ABSTRACT FROM AUTHOR]