Gustavsenclarke6368

Particulate air pollution in cities comprises a variety of harmful compounds, including fine iron rich particles, which can persist in the air for long time, increasing the adverse exposure of humans and living things to them. We studied street tree (among other species, Cordyline australis, Fraxinus excelsior and F. pensylvanica) barks as biological collectors of these ubiquitous airborne particles in cities. Properties were determined by the environmental magnetism method, inductively coupled plasma optical emission spectrometry and scanning electron microscopy, and analyzed by geostatistical methods. Trapped particles are characterized as low-coercivity (mean ± s.d. value of remanent coercivity Hcr = 37.0 ± 2.4 mT) magnetite-like minerals produced by a common pollution source identified as traffic derived emissions. Most of these Fe rich particles are inhalable (PM2.5), as determined by the anhysteretic ratio χARM/χ (0.1-1 μm) and scanning electron microscopy ( less then 1 μm), and host a variety of potentially toxic elements (Cr, Mo, Ni, and V). Contents of magnetic particles vary in the study area as observed by magnetic proxies for pollution, such as mass specific magnetic susceptibility χ (18.4-218 × 10-8 m3 kg-1) and in situ magnetic susceptibility κis (0.2-20.2 × 10-5 SI). The last parameter allows us doing in situ magnetic biomonitoring, being convenient because of species preservation, measurement time, and fast data processing for producing prediction maps of magnetic particle pollution.Recycled materials were used in three types of green sorption media for nutrient removal and possible recovery in high nutrient-laden agricultural discharge and stormwater runoff. The three types of green sorption media included in this comparative study were two new aluminum-based green environmental media (AGEM) and one existing iron-filings based green environmental media (IFGEM). The corresponding adsorption isotherm, thermodynamics, and kinetics models were simulated based on isotherm studies to determine their removal efficiency and potential for recovery of nitrate, phosphate, and ammonia when used as a soil amendment in crop fields or in a filter for water treatment. AGEM-2 exhibited the shortest contact time required to achieve nutrient removal above 80% with an average of 7 h, followed by AGEM-1 and IFGEM with 10.6 and 28 h, respectively. Natural soil was included as a control and exhibited minimal nutrient removal. Ammonia, which may be recovered as fertilizer for drop fields in a soil-water-waste nexus, was generated by all three green sorption media mixes, therefore indicating their potential for use as soil amendments in agricultural and forested land after engineering filter applications. The kinetics analysis indicated that nitrate adsorption follows pseudo-first-order kinetics, while phosphate adsorption follows pseudo-second-order kinetics. The Gibbs free energy indicated that most of the adsorption reactions proceeded as exothermic. Lastly, a few equilibrium models, including the Langmuir, Freundlich, First Modified Langmuir, Temkin, Jovanovic, and Elovich models, were ranked and three were selected for use with IFGEM, AGEM-1, and AGEM-2, respectively, as below (1) Langmuir, (2) Freundlich, and (3) First Modified Langmuir, according to three indices.Waste date palm-derived biochar (DPBC) was modified with nano-zerovalent iron (BC-ZVI) and silica (BC-SiO2) through mechanochemical treatments and evaluated for arsenate (As(V)) removal from water. The feedstock and synthesized adsorbents were characterized through proximate, ultimate, and chemical analyses for structural, surface, and mineralogical compositions. BC-ZVI demonstrated the highest surface area and contents of C, N, and H. A pH range of 2-6 was optimum for BC-ZVI (100% removal), 3-6 for DPBC (89% removal), and 4-6 for BC-SiO2 (18% removal). Co-occurring PO43- and SO42- ions showed up to 100% reduction, while NO3- and Cl- ions resulted in up to 26% reduction in As(V) removal. Fitness of the Langmuir, Freundlich and Redlich-Peterson isotherms to As(V) adsorption data suggested that both mono- and multi-layer adsorption processes occurred. BC-ZVI showed superior performance by demonstrating the highest Langmuir maximum adsorption capacity (26.52 mg g-1), followed by DPBC, BC-SiO2, and commercial activated carbon (AC) (7.33, 5.22, and 3.28 mg g-1, respectively). Blockage of pores with silica particles in BC-SiO2 resulted in lower As(V) removal than that of DPBC. Pseudo-second-order kinetic model fitted well with the As(V) adsorption data (R2 = 0.99), while the Elovich, intraparticle diffusion, and power function models showed a moderate fitness (R2 = 0.53-0.93). The dynamics of As(V) adsorption onto the tested adsorbents exhibited the highest adsorption rates for BC-ZVI. As(V) adsorption onto the tested adsorbents was confirmed through post-adsorption FTIR, SEM-EDS, and XRD analyses. Adsorption of As(V) onto DPBC, BC-SiO2, and AC followed electrostatic interactions, surface complexation, and intraparticle diffusion, whereas, these mechanisms were further abetted by the higher surface area, nano-sized structure, and redox reactions of BC-ZVI.Incommensurate stacking between two different types of two-dimensional layered materials furnished the weak interfacial interaction due to the mismatch of their lattice structure, which can be harnessed for development of new generation lubricant additives. Herein, a facile approach is presented to synthesize the ZnO-decorated reduced graphene oxide/MoS2 (Gr-MS-Zn) nanosheets. The Fourier transform infrared, X-ray photoelectron spectroscopic, Raman, and transmission electron microscopic analyses confirmed the preparation of Gr-MS-Zn heterostructure. The MoS2 nanosheets having 3-7 molecular lamellae are thoroughly distributed over the graphene skeleton via weak interfacial interaction. MK-0822 The curved and bent structure of MoS2 nanosheets grown over the graphene lamellae subsidized the cohesive interaction and furnished the stable dispersion of Gr-MS-Zn in the fully formulated engine oil. The minute dose of Gr-MS-Zn as a nano-additive to engine oil significantly enhanced the tribological performance between the steel-steel tribopair by decreasing the friction (37%) and the wear volume (87%).