Despite all its advantages and potential, cross-linking enzyme aggregate (CLEA) technology is still not applied at an industrial scale for enzyme insolubilization for bioremediation purposes. In this study, the enzyme polymer engineered structure (EPES) method was used to enhance CLEA stability and reuse. A crude laccase from Trametes hirsuta was successfully insolubilized to form EPES-CLEAs. The polymeric network provided excellent stability (> 90%) to CLEAs after a 24-h incubation in a non-buffered municipal wastewater effluent (WW), and the biocatalysts were recycled using a centrifugation process. While CLEAs activity dropped to 17%, EPES-CLEAs showed a laccase activity retention of 67% after five cycles of 2,2’-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) oxidation. After 8 h of treatment in WW, the EPES-CLEAs were equally as effective in removing cannabidiol (CBD) as the free-LAC (~ 37%). This research demonstrates that the EPES method is a promising alternative for CLEA stabilization and reuse in environmental conditions.

Water level variation substantially affects the trophic levels in a lake. The primary objective of this research is to investigate the impact of water level fluctuation on sediment and phosphorous (P) dynamics in Tonle Sap Lake (TSL), Cambodia. Water samples were collected from eight cross sections in a lake at 3-month intervals for 3 years, during the low-water period (March and June) and high-water period (September and December) from December 2016 to June 2019. Water quality parameters—temperature, conductivity, salinity, dissolved oxygen, pH, oxidation reduction potential, chlorophyll-a (Chl-a), and blue green algae—were measured using an EXO⁽ᴿ⁾ sensor. The sedimentation and resuspension rates of the sediment were measured using a sediment trap. Sediments were collected during the low-water period of March 2017. The sediment resuspension condition was simulated via centrifugation (150 rpm, end-to-end mechanical shaker, room temperature 25 °C for 24 h) to assess phosphorous dynamics. The P content in the bed sediment was fractionated to obtain loosely bound, metal oxide bound, apatite bound, and organic bound P. Sediment resuspension was greater during the low-water period (< 1 m) than that during the high-water period (> 4.8 m). The sites exhibited significant variation (p < 0.05) in terms of dissolved oxygen, pH, oxidation–reduction potential, Chl-a, and depth during low- and high-water periods. In general, the Chl-a concentration throughout the sampling campaigns ranged between 1.7 and 9.0 μg/L, suggesting the existence of a mesotrophic state in the TSL. The zero equilibrium P concentration of sediment in TSL was greater when the sediment was under the resuspension condition (18.9 ± 3.0 μg/L) than under the static condition (7.7 ± 1.1 μg/L). In TSL, during resuspension (low-water) conditions, sediments act as a source and release P (apatite bound, loosely bound, metal oxide bound, and soluble reactive P). However, in static (high-water) conditions, sediments act as a sink by adsorbing P from the overlying water. Graphical abstract

A new nickel ion, magnetic imprinted polymer was fabricated through the precipitation polymerization process, using amine-functionalized silica-capped iron oxide particles as a core material, and 4-vinyl pyridine as complexing agent methacrylic acid as functional monomer. The resulted magnetic adsorbent was employed to eliminate toxic Ni²⁺ ions from industrial wastewater. The different parameters were optimized, such as pH, shaking speed, and adsorbent dose, to obtain the maximum adsorption capacity. The synthesized material showed high selectivity coefficient for Ni⁺² ions in the presence of other competitive ions and followed pseudo-second-order kinetics and Langmuir isotherm. A good adsorption capacity of 158.73 mg g⁻¹ was obtained at optimized pH 6 in the concentration of 5 mg L⁻¹ nickel ions aqueous solution. The limit of detection, quantification, and the percent relative standard deviation was found to be 0.58, 1.93, and 3.4%. This proves the excellent performance of prepared magnetic Ni(II) ion-imprinted polymer for selective detoxification of Ni²⁺ ions from real aqueous samples. Due to tunable magnetic properties, the prepared MMIPs are highly selective and sensitive and highly porous in nature; due to excellent magnetic properties, there is no need for centrifugation. Just use external magnetic field, it has good reusability. Showing preparation of Ni (II) imprinted magnetic polymer.

This study presents an analytical strategy named silica nanoparticles (Si-NP) based pipette tip solid phase extraction (PT-SPE) method for the trace level determination of cadmium in mineral water samples. Slotted quartz tube flame atomic absorption spectrophotometry (SQT-FAAS) was used to determine the cadmium analyte. Si-NPs synthesized from rice husk were used to preconcentrate/extract the cadmium ions. Adsorbent properties of Si-NPs were examined by SEM analysis and the size of nanoparticles was found in nanoscale. The extraction/preconcentration and phase separation steps are carried out simultaneously which greatly reduces the extraction time by eliminating the need for centrifugation step before phase separation. The effect of all experimental parameters on the efficiency of the developed method was examined and optimized utilizing univariate optimization strategy. The linear calibration graph of the developed method showed a good linearity between 0.60 and 20 µg/L and the limit of detection was calculated as 0.16 µg/L. The presented method showed an approximately 194-fold enhancement in detection power compared to traditional FAAS. The developed method’s applicability to real samples was validated through spiking experiments in mineral water samples using the matrix matching strategy. The percent recoveries calculated were ranged between 92 and 98% with RSD values lower than 10%, confirming the applicability of the developed method for the precise determination of cadmium in mineral water samples. The developed method offers a simple and rapid extraction/preconcentration of the target analyte from the aqueous sample solution.

The solubilization laws of pollutants in micelles and their separation efficiency are very important in the successfully efficient application of micellar enhanced ultrafiltration (MEUF). The solubilization behavior of o-toluidine (OT) and tricyclazole (TC) into sodium dodecyl sulfate (SDS) micelles in MEUF was studied using nonlinear equation sets for concentration analysis, which resolved the issue on the overlap of absorption spectra of multicomponent compounds restricting the application of conventional ultraviolet (UV) spectroscopic method. The solubilization isotherms for both pollutants could be best explained by the Langmuir-Freudlich model (R²>0.99) followed by the modes of Langmuir and Freudlich, inferring the complexity of solubilization mechanism and solubilization advantage of monolayer over multilayer. The calculated thermodynamic parameters (ΔG⁰, ΔH⁰ and ΔS⁰) indicated that this process was endothermic and spontaneous. The solubilization of OT and TC well followed the pseudo second-order and pseudo first-order kinetics, respectively. The separation and recovery of SDS solubilizing these two pollutants were also investigated through lowering solution temperature to 2 °C followed by centrifugation. The best recovery rate of about 66% for SDS was achieved containing 10 and 5% of each initial amount of OT and TC, respectively, at near-neutral solution pH value. The recovery of SDS could decrease to some extent under alkaline and acidic conditions.

With the development of modern industry and agriculture, plentiful microplastics (MPs) were produced as a result of the abuse of plastic. The widespread presence of MPs in soils has caused coastal ecological environment pollution. Previous research has shown that fertilizer is one pathway for the entry of MPs into agricultural soils. Meanwhile, livestock manure is a major fertilizer for crops, and the application of livestock manure compost creates a potential pathway for MPs to enter soils. Thus, MPs may exist in livestock manure from the process of livestock breeding and ultimately contaminate agricultural soils. Based on the increasing attention to MP pollution, manure-born MPs will attract more interest in the future. Thus, the present study compares the extraction effects of centrifugation with fractional distillation, and an improved method is introduced to extract polypropylene (PP) from different types of swine manure. The numbers of particles and fibers were determined using a camera (MS60) connected to a stereomicroscope (Mshot MZ62), and the results showed that the recovery rate of plastic particles in swine manure based on different added numbers ranged from 71.43% ± 8.36 to 96.67% ± 3.33 with the centrifugation method, and only 31.11% ± 10.56 to 43.33% ± 12.56 using fractional distilling. The recovery rate for fibers was generally higher than for particles, especially using centrifugation, and ranged from 95.67% ± 1.58 to 100% ± 0, while the rate of fiber recovery using fractional distillation ranged from 39.44% ± 10.66 to 39.44 ± 10.66. The results of recovery rates using the two methods show that the effect of extraction by centrifugation is superior to the method of fractional distillation, with a recovery rate of approximately 100% for fibers and 90% for particles. The recovery number of microplastics evaluated with a line regression model was acceptable. Graphical abstract