Study on the Tribological Properties of F-T DS/ZnFe-LDH Composite Lubricating Material

The homemade soot capture device was used to burn Fischer-Tropsch synthetic diesel (F-T diesel) in order to simulate the combustion of F-T diesel in the engine and collect its soot (F-T DS, FS). The zinc-iron hydrotalcite (ZnFe-LDH) and the composite materials of FS and ZnFe-LDH (F-T DS/ZnFe-LDH, FS/ZnFe-LDH) were prepared by hydrothermal synthesis, and the similarities and differences in tribological characteristics of the above three lubricating materials such as 10# white oil (10# WO) lubricant additives were investigated. FS is an aggregation composed of amorphous carbon and graphite microcrystals. ZnFe-LDH is mainly composed of nanosheets, Zn, and Fe hydroxide particles, with a high degree of crystallization, while FS/ZnFe-LDH is a “sandwich layer” composed of nanosheets and soot particles. Because of the addition of cetyltrimethylammonium bromide and the grafting of a long carbon chain lipophilic group in the preparation process, FS/ZnFe-LDH has better anti-wear properties than the FS and ZnFe-LDH Effect. When FS/ZnFe-LDH is added at 0.2 wt.%, the average friction coefficient (AFC) and average wears scar diameter (AWSD) are at their lowest. Compared with pure 10# WO, the minimum values of AFC and AWSD have dropped by 36.84% and 22.58%, respectively. XPS analysis of the wear scar surface shows that when ZnFe-LDH and FS/ZnFe-LDH are used as lubricating additives of 10# WO, together with the organic matter in the white oil and the iron element in the friction pair, tribochemistry occurs under the combined action of the adsorption force and the tribochemical reaction, a friction protection film containing four elements of C, O, Fe, and Zn is formed on the surface of the wear scar, which effectively reduces the wear and reduces the friction coefficient.

Novel eco-friendly low cost and energy efficient synthesis of (Nd–Pr–Dy)2Fe14B magnetic powder from monazite concentrate

Syntheses of Nd2Fe14B magnetic powder by conventional method is a complicated multi-step process, which produces harmful pollutants and consumes a huge amount of energy and resources. Herein we report a simple chemical route for the preparation of (Nd–Pr)2Fe14B magnetic powder using monazite concentrate as a precursor. Th, U, Sm, and La impurities were removed from monazite leachate by roasting, solvent extraction and leaching the concentrate. Purified leachate consisting of Nd and Pr Chlorides was added to the FeCl3 solution, and the solution produced was co-precipitated with NaOH. RE and Fe hydroxide precipitates were converted to the oxides by annealing at 700 °C. Boric acid and CaH2 were added in the RE and Fe oxides produced, and this mixture was reduced and diffused to (Nd–Pr)2Fe14B. Magnetic properties of the (Nd–Pr)2Fe14B produced were enhanced by introducing antiferromagnetic coupling, induced by Dy addition and efficient removal of CaO byproduct through ball milling in ethanol which increased the BHmax from 3.9 to 11.45 MGOe. Process reported is energy efficient, environment-friendly, time saving and low-cost.

Biochar-Materials for Remediation on Swamplands: Mechanisms and Effectiveness

<p class="JSDLKatakunci"><strong>Abstra</strong><strong>ct</strong><strong>.</strong> The purpose of this paper is to synthesize all research results qualitatively to explore the potential of biochar as a remediation agent in swamps, including its mechanism, and effectiveness. The soil in swampland is characterized by the presence of pyrite (FeS₂) which results in high acidity (soil pH &lt;3.5). The reduction process in swamps produces high amounts of ferrous iron (Fe²⁺) which is then released into the environment. The mechanism of iron (Fe) poisoning is indicated by the inhibition of nutrient uptake because the roots are covered with iron. This disturbes the root function as a nutrient absorber. Recent research shows that biochar could be used as an approach to reduce soil pollution in swamps through metal immobilization processes. This review paper uses a qualitative method with meta-aggregation approach based on the Francis-Baldesari method (2006). Principally, the soil remediation mechanism using biochar does not remove metals but accumulate them into hydroxide or carbonate deposits with the help of existing microorganisms. Provision of rice husk Biochar can increase the pH value reaching ≥5.0 and grain yield by 20% in intensively cultivated tidal swamps. Increasing the pH value of the soil will supports the formation of Fe hydroxide deposits which are accumulated on rice roots.</p><p class="JSDLKatakunci"> </p><p><strong>Abstrak. </strong>Tujuan penulisan paper ini adalah mensintesis seluruh hasil penelitian secara kualitatif untuk<strong> </strong>menggali potensi biochar sebagai bahan remediasi pada lahan rawa meliputi mekanisme, dan efektivitasnya. Tanah di lahan ini dicirikan oleh keberadaan pirit (FeS₂) yang menghasilkan keasaman tinggi (pH tanah &lt;3,5). Proses reduksi di lahan rawa menghasilkan besi ferro (Fe²⁺) dalam jumlah tinggi dan dilepaskan ke lingkungan. Mekanisme keracunan besi (Fe) ditunjukkan dengan terhambatnya serapan hara karena perakaran diselimuti oleh besi sehingga fungsi akar sebagai penyerap unsur hara terganggu. Penelitian terbaru menunjukkan bahwa pemanfaatan biochar sebagai salah satu pendekatan untuk mengurangi pencemaran tanah di lahan rawa melalui proses immobilisasi logam. Paper review ini menggunakan metode kualitatif berdasarkan metode Francis-Baldesari (2006) dengan pendekatan metaagregasi (meta-aggregation). Mekanisme remediasi tanah menggunakan biochar prinsipnya tidak menghilangkan logam tetapi mengakumulasinya menjadi endapan hidroksida maupun karbonat dengan bantuan mikroorganisme yang ada. Pemberian Biochar sekam padi dapat meningkatkan nilai pH mencapai ≥5,0 dan hasil gabah sebesar 20% di lahan rawa pasang surut yang intensif dibudidayakan. Peningkatan nilai pH tanah mendukung pembentukan endapan hidroksida Fe yang diendapkan pada akar padi.</p>

Occurrence and significance of smectite in the Pliensbachian (Lower Jurassic) at Lókút (Bakony Mts., Hungary)

Although the Mesozoic rocks of the Transdanubian Range have been the subject of a multitude of different studies, mineralogical research is largely underrepresented. The clay mineralogy of Lower Jurassic (especially the Pliensbachian and Toarcian) strata was broadly investigated earlier; however, systematic high-resolution clay mineralogical studies remain scarce. Here we present a mineralogical study focusing on the Upper Pliensbachian strata of the Lókút-Hosszúárok section, located near the Eplény Manganese Ore Field. We identified dioctahedral smectite, randomly interstratified illite/smectite, illite as 10 Å phyllosilicate, quartz and cristobalite. Based on our new results we propose that the smectite was formed by aging of Mg or Fe hydroxide-silica precipitates. The smectite and cristobalite were presumably formed from the siliceous tests of radiolarians, whose abundance was controlled by a local upwelling system. The occurrence of Pliensbachian smectite in the Lókút outcrop shows similarities with the Úrkút smectites known from both Pliensbachian and Toarcian strata, which implies that similar processes controlled the sedimentation during the Pliensbachian as well as during the black (gray) shale-hosted ore accumulation in the Eplény and Úrkút basins.

Microbial nitrification and acidification of lacustrine sediments deduced from the nature of a sedimentary kaolin deposit in central Japan

Kaolin deposits in the Seto-Tono district, central Japan, were formed by intense kaolinization of lacustrine arkose sediments deposited in small and shallow inland lakes in the late Miocene. Based on mineralogical and stable isotopic (Fe, C, N) studies of Motoyama kaolin deposit in the Seto area, we concluded that it was formed by microbial nitrification and acidification of lacustrine sediments underneath an inland lake. Small amounts of Fe–Ti oxides and Fe-hydroxide in the kaolin clay indicated that iron was oxidized and leached during the kaolinization. The field occurrences indicate that leached ferric iron precipitated on the bottom of the kaolin deposit as limonite crusts, and their significantly fractionated Fe isotope compositions suggest the involvement of microbial activity. The C/N ratios of most of the kaolin clay are distinctly higher than those of modern lacustrine sediment. Although, the possibility of a low-temperature hydrothermal origin of the kaolin deposit cannot be completely ruled out, it is more likely that acidification by dilute nitric acid formed from plant-derived ammonia could have caused the kaolinization, Fe oxidation and leaching. The nitrate-dependent microbial Fe oxidation is consistent with dilute nitric acid being the predominant oxidant.