Preliminary Analyses of Controlled Release of Potassium Permanganate Encapsulated in Polycaprolactone

Potassium permanganate (KMnO4) has been used widely as an oxidant for remediation of contaminated soil and water systems. The present study evaluates the release of this oxidant from Polycaprolactone (PCL) polymer as part of a patented controlled release process (CRP) to be applied for targeted removal of contaminants from water. KMnO4 was encapsulated into PCL at a 1:5 oxidant to polymer ratio and placed in batch reactor systems with reagent water to be evaluated over a 96 hour period. SEM images showed that over time, the number of cavities and their sizes increased on the waxy surface of the PCL polymer. The experimental data from the release of KMnO4 from PCL was found to fit non-Fickian diffusion model after dissolution (R2 = 0.93) similar to other systems that describe the dispersal of other oxidants from wax matrices. In addition, the model parameters for data of this present study were also found to be comparable to previous release studies with the same oxidant encapsulated in different wax matrices at similar ratios. Overall, the similarity of release data between the diversity of polymers shows that the controlled release biodegradable polymer utilizing PCL provides effective release of the KMnO4 with the added benefit biodegradable nature of PCL.

Comparison of Release Efficiencies for the Controlled-Release of Potassium Permanganate in Polycaprolactone

The application of controlled release materials in tandem with chemical oxidants has become an emerging topic within the field of environmental treatment. The controlled release kinetic and mechanistic relationship between these components is important to understand a controlled release system. Potassium permanganate (KMnO4) was used as the encapsulated material integrated into polycaprolactone (PCL) producing controlled release biodegradable polymer (CRBP) pellets. In this study, batch experiments were used to examine the release kinetics from the discharge of the pelletized encapsulated oxidant into aqueous systems at various KMnO4:PCL ratios of 1:5, 2:5, and 3:5 by mass. Experimental results indicated as the amount of KMnO4 in the PCL polymer pellets increased, a greater fraction of the oxidant was released as a function of time. The resultant data best fit a linearized diffusion model equation. Additionally, a comparison-controlled release study was conducted that contained the same oxidant at similar mass ratios. Release kinetics determined from this study could lead to effective implementation of CRBP systems and could suggest that CRBP encapsulated with KMnO4 could serve as a promising controlled release technology in a long-term and controlled manner.

A Systematic Review and Meta-Analysis of Water Quality Indices

Water quality indices (WQI) are useful tools for indicating the suitability of water for an expected use. However, they can suffer from some problems. The objective of this paper was to analyze the development of WQI to determine which parameters are used in water quality assessment and to discuss the characteristics of WQI. To screen articles on WQI, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method is applied to include or exclude articles. Four necessary steps are needed to design WQI: parameter selection, standardization, weighting and aggregation. A set of six methods of aggregations of sub-indices are identified: the arithmetic mean, the geometric mean, the root square, the logarithmic function, the fuzzy inference and the minimum operator. The problems encountered for the overall index are different according to the form of aggregation. They are eclipsing, ambiguity, rigidity or flexibility, adaptability and compensation. The chemical parameters (70%) are the most used in the development of WQI with the physical parameters used at 24% and the biological parameters at 6%. Dissolved oxygen (DO, 87%), total coliforms (87%), biological oxygen demand (BOD, 73%), pH (73%), temperature (67%), turbidity (60%), ammonia (53%), ammonium (47%) and total dissolved solids (47%) are the most commonly used parameters for water quality assessment.

Microplastics in landfill leachate:Sources,detection,occurrence,and removal

Due to the accumulation of an enormous amount of plastic waste from municipal and industrial sources in landfills,landfill leachate is becoming a significant reservoir of microplastics.The release of microplastics from landfill leachate into the environment can have undesirable effects on humans and biota.This study provides the state of the science regarding the source,detection,occurrence,and remediation of microplastics in landfill leachate based on a comprehensive review of the scientific literature,mostly in the recent decade.Solid waste and wastewater treatment residue are the primary sources of microplastics in landfill leachate.Microplastic concentration in raw and treated landfill leachate varied between 0-382 and 0-2.7 items L^(−1).Microplastics in raw landfill leachate are largely attributable to local plastic waste production and solid waste management practices.Polyethylene,polystyrene,and polypropylene are the most prevalent microplastic polymers in landfill leachate.Even though the colors of microplastics are primarily determined by their parent plastic waste,the predominance of light-colored microplastics in landfill leachate indicates long-term degradation.The identified morphologies of microplastics in leachate from all published sources contain fiber and fragments the most.Depending on the treatment method,leachate treatment processes can achieve microplastic removal rates between 3%and 100%.The review also provides unique perspectives on microplastics in landfill leachate in terms of remediation,final disposal,fate and transport among engineering systems,and source reduction,etc.The landfill-wastewater treatment plant loop and bioreactor landfills present unique difficulties and opportunities for managing microplastics induced by landfill leachate.