Goethite Research Articles (Page 1)

Environmental context Plastic pollution is a growing crisis, with tiny microplastic (MP) particles spreading through our environment and potentially affecting ecosystems in ways we do not fully understand. This study found that thermoplastic-bead MPs and polyethylene terephthalate MPs can chemically interact with naturally occurring minerals like goethite, altering the surfaces of the MPs and potentially influencing how pollutants and microbes interact with the altered particles. Understanding these surface changes is crucial for predicting how MPs behave in nature and assessing their long-term environmental impact. Rationale This study investigated how goethite (GT) affects the surface of thermoplastic-bead microplastics (TPB-MPs) and polyethylene terephthalate MPs (PET-MPs) under simulated natural conditions. Chosen for its prevalence and roles in environmental geochemistry, GT interacts with MPs and influences their behavior and pollutant interactions. The hypothesis was that GT adsorption alters MP surface chemistry, affecting environmental biogeochemistry. Methodology MP surfaces were examined before and after GT treatment using X-ray photoelectron microscopy (XPS). Prior Fourier–transform infrared (FT-IR) analysis identified TPB-MPs as PET-based materials, indicating compositional similarity. XPS revealed the chemical compositions and electron binding energies in PET-MPs and TPB-MPs before and following GT adsorption. Results GT adsorption decreased surface carbon and increased oxygen content more in PET-MPs than TPB-MPs. PET-MPs showed stronger charge transfer and hydrogen bonding with GT, whereas TPB-MPs interactions were weaker and dominated by Van der Waals forces. Variations in peak intensity indicated enhanced C–O and O–C═O bonds and masking of C–C/C═C bonds in PET-MP. TPB-MP’s interactions with GT were weaker. Shifts in Fe2p doublet suggested chemical changes from GT adsorption. Discussion The results show that GT changes the surface chemistry of PET-MPs, enhancing their environmental transformation and reactivity. Binding energy shifts indicate surface hydrogen bonding and potential oxidation and charge transfer, highlighting GT’s role in mediating MP–mineral interactions. TPB-MPs exhibit weaker GT adsorption and fewer chemical changes, influencing their persistence and interactions with pollutants. Future research should explore oxidative transformation and microbial responses to MPs with mineral coatings. GT adsorption alters surface composition, electron scattering, and peak intensities mainly through physical interactions, with chemical effects needing further study.

Effect of calcium and phosphorus on ammonium and nitrate nitrogen adsorption onto iron (hydr)oxides surfaces: CD-MUSIC model and DFT computation

The diffusive processes that occur in minerals involve chemical and physical surface phenomena of great interest that allow for understanding the mobility of different anions of environmental importance. One of them is glyphosate, which is widely used as a pesticide. In this work, we performed Hubbard-corrected density functional theory (DFT + U) calculations to study the adsorption and surface diffusion of methylphosphonic acid (MPA), as a model of glyphosate, on the (010) plane of goethite (GOT), one of the most important Fe(III) minerals in soils and sediments. In particular, the MPA adsorption was studied at the GOT-water interface, finding a strong covalent character in the bond. We also corroborated the occurrence of double proton transfer (MPA to GOT and GOT to GOT). Finally, activation energy barriers were calculated to estimate the half-lives for molecular diffusion, showing that MPA moves almost 3000 times slower than water at the GOT surface.

Enhanced cadmium removal by biochar and iron oxides composite: Material interactions and pore structure

Retardation factors in controlling the transport of inorganic, organic, and particulate phosphorus in fluvo-aquic soil

Microbial community characteristics of cadmium speciation transformation in soil after iron-based materials application

Impacts of wet-dry alternations on cadmium and zinc immobilisation in soil remediated with iron oxides

Remediation of cadmium and lead contaminated soils using Fe-OM based materials

The transport of nanoplastics (NPs) through porous media is influenced by dissolved organic matter (DOM) released from agricultural organic inputs. Here, cotransport of NPs with three types of DOM (biocharDOM (BCDOM), wheat strawDOM (WSDOM), and swine manureDOM (SMDOM)) was investigated in saturated goethite (GT)-coated sand columns. The results showed that codeposition of 50 nm NPs (50NPs) with DOM occurred due to the formation of a GT–DOM–50NPs complex, while DOM loaded on GT-coated sand and 400 nm NPs (400NPs) aided 400NPs transport due to electrostatic repulsion. According to the quantum chemical calculation, humic acid and cellulose played a significant role in 50NPs retardation. Owing to its high concentration, moderate humification index (HIX), and cellulose content, SMDOM exhibited the highest retardation of 50NPs transport and promoting effect on 400NPs transport. Owing to a high HIX, the effect of BCDOM on the mobility of 400NPs was higher than that of WSDOM. However, high cellulose content in WSDOM caused it to exhibit a 50NPs retardation ability that was similar to that of BCDOM. Our results highlight the particle size selectivity and significant influence of DOM type on the transport of NPs and elucidate their quantum and colloidal chemical-interface mechanisms in a typical agricultural environment.

Effects of selected functional groups on nanoplastics transport in saturated media under diethylhexyl phthalate co-contamination conditions

Adsorption studies of acid dye – Eosin yellow on date palm seeds, goethite and their composite

The adsorption of Methylene Blue (MB) onto Raw Date-palm Seeds (RDS), Thermally Activated Carbon (TAC), Chemically Activated Carbon (CAC), Goethite (GT) and their Composite (COM) were studied using batch equilibrium technique. Variations of sorptive properties such as initial solution concentration, pH, adsorbent dosage, contact time and temperature had a remarkable influence on the adsorption processes. The data fitted well tested isotherm models in the order; Langmuir (R2 = 0.942 and 0.963) > Freundlich (0.886 and 0.948) > Temkin (0.869 and 0.83) for GT and COM respectively. That of CAC and TAC was best described by Freundlich and Langmuir models respectively while RDS showed very poor fittings. Pseudo-second order and film diffusion models best described the adsorption kinetics. The adsorption was feasible, spontaneous (∆G < 0) and exothermic (except MB-CAC with ∆H being positive). The combined results of isotherm, kinetics and thermodynamic studies suggested a combined chemisorptions and physisorptions processes. Also, the kinetic modeling suggested that intra-particle and film diffusions occurred simultaneously and/or in combination with other processes in the mechanism of adsorption.

Soil colloids significantly facilitate the transport of contaminants; however, little is known about the effects of highly reactive iron oxide and the most representative organic matter on the transport of soil colloids with different physicochemical properties. This study investigated the effects of goethite (GT) and humic acid (HA) on the sedimentation and transport of soil colloids using settling and column experiments. The stability of soil colloids was found to be related to their properties and decreased in the following order: black soil colloids (BSc) > yellow soil colloids (YSc) > fluvo-aquic soil colloids (FSc). Organic matter increased the stability of BSc, and ionic strength (Ca2+) promoted the deposition of FSc. Colloids in individual and GT colloids (GTc) coexistence systems tended to stabilize at high pH and showed a pH-dependence whereby the stability decreased with decreasing pH. The interaction of GTc and kaolinite led to a dramatic sedimentation of YSc at pH 4.0. HA enhanced the stability of soil colloids, especially at pH 4.0, and obscured the pH-dependent sedimentation of soil colloids. The transport ability of soil colloids was the same as their stability. The addition of GT retarded the transport of soil colloids, which was quite obvious at pH 7.0. This retardation effect was attributed to the transformation of the surface charge of sand from negative to positive, which increased the electrical double-layer attraction. Although sand coated with GT–HA provided more favorable conditions for the transport of soil colloids in comparison to pure sand, the corresponding transport was relatively slow. This suggests that the filtration effect, heterogeneity, and increased surface roughness may still influence the transport of soil colloids.

This study demonstrated the ability of a Landsat-8 OLI multispectral data to identify and delineate hydrothermal alteration zones around auriferous prospects within the crystalline basement, North-western Nigeria. Remote sensing techniques have been widely used in lithological, structural discrimination and alteration rock delineation, and in general geological studies. Several artisanal mining activities for gold deposit occur in the surrounding areas within the basement complex and the search for new possible mineralized zones have heightened in recent times. Systematic Landsat-8 OLI data processing methods such as colour composite, band ratio and minimum noise fraction were used in this study. Colour composite of band 4, 3 and 2 was displayed in Red-Green- Blue colour image to distinguish lithologies. Band ratio image displayed in red was used to highlight ferric-ion bearing minerals (hematite, goethite, jarosite) associated with hydrothermal alteration, band ratio image displayed in green was used to highlight ferrous-ion bearing minerals such as olivine, amphibole and pyroxenes, while ratio image displayed in blue was used to highlight clay minerals, micas, talc-carbonates, etc. Band rationing helped to reduce the topographic illumination effect within images. The result of this study showed the distribution of the lithological units and the hydrothermal alteration zone which can be further prospected for mineral reserves.

Acid mine drainage (AMD) is one of the most important research subjects of mine environmental treatment and remediation. In recent years, quite a little scholars, at home and abroad, have studied the types, characteristics, formation sequence and assemblages of a majority of secondary mineral resources in acid mine drainage, and so on. And on this basis the secondary minerals, such as jarosite and schwertmannite, were experimentally tested, and the adsorption and passivation ability of several main secondary minerals to heavy metal ion was tested as well. In this paper, the types of secondary minerals found in the acid mine drainage which formed in different environments were summarized systematically and elaborately. In the past a dozen years, the formation sequence and assemblages of these secondary minerals were made a preliminary study. The formation conditions, chemical synthesis methods and conditions of jarosite and schwertmannite, Basaluminite, goethite, hematite, and other main secondary minerals which may have the application value were elaborately discussed and analyzed. And furthermore, the adsorption capacity and passivation of heavy metal ions was analyzed. In the end, the application prospects and application ways of these typical main secondary minerals in acid mine drainage were summed up.

Goethite with protuberant lychee morphology has been synthesized that accomplishes C-H activation of N-methylanilines to generate α-aminonitriles; the catalyst takes oxygen from air and uses it as a co-oxidant in the process.

اسکارن مس- آهن آوان در نتیجه نفوذ باتولیت گرانیتوئیدی قره داغ به‌ داخل سنگهای کربناته ناخالص کرتاسه بالایی تشکیل شده است. اسکارن آوان متشکل از پهنه های مرمر، اگزواسکارن و اندواسکارن بوده و بخش اصلی آن پهنه اگزواسکارن، است. بررسیهای کانی شناسی بیانگر آن است که پهنه اگزواسکارن شامل زیرپهنه های گارنت اسکارن، پیروکسن- گارنت اسکارن و کانه اسکارن است. مهمترین کانی کالک سیلیکاته بی آب در پهنه اگزواسکارن، گارنت و ترکیب آن اوگراندیتی (Ad53-89) است. برخی بلورهای گارنت، منطقه‌بندی دارد و ترکیب آنها به طرف حاشیه‌ها به آندرادیت خالص (Ad99) میل می‌کند. کلینوپیروکسن موجود در زیرپهنه پیروکسن- گارنت اسکارن از نوع دیوپسید (Di75-96) است. زیرپهنه کانه اسکارن از کانه‌های مگنتیت، هماتیت، پیریت، کالکوپیریت، بورنیت، مالاکیت و گوتیت تشکیل شده است. وجود میزان محدود ولاستونیت در مجموعه کانی شناسی اسکارن آوان، هم‌رشدی بلورهای گارنت و کلینوپیروکسن و نبود هاله واکنشی بین این دو کانی و نبود بافتهای جانشینی نشان‌دهنده آن است که این کانیها به‌صورت هم‌زمان در محدوده دمایی C°600- 430 و فوگاسیته اکسیژن بیشتر از 10-26 تشکیل شده‌اند.

This paper aims to chemically and mineralogically characterize the Malaysian low grade manganese ore (LGMO). The optical microscope, and scanning electron microscope (SEM) fitted with an energy-dispersive x-ray analyzer (EDX) were used for ore morphology assessment, mineral liberation analysis, particle texture studies, grain size distribution and mineral association assessment. X-ray fluorescence (XRF) and X-ray diffraction (XRD) were used to determine the LGMO’s composition and to identify mineral phases, respectively. SEM images with EDX analysis revealed various optical characteristics of the ore, while XRF results showed that the major elements present in this LGMO are Si, (16.95%), followed by Mn, Fe and Al (at 13.17%, 4.63% and 4.70%, respectively). Phase analysis by XRD meanwhile, revealed the presence of α-quartz, pyrolusite and aluminum-substituted goethite. The natural grain-size distribution and texture (observed using optical and backscattered image analysis) revealed that manganese liberation was observed at particle sizes below 150 µm. This indicates that particle size has a significant effect in the recovery of the manganese oxide. The data and information obtained from this characterization study will aid in the identification and the design of a suitable treatment method for this local LGMO, and with that, the possibility of exploiting this deposit as a local source of manganese.

Underestimation of phosphorus fraction change in the supernatant after phosphorus adsorption onto iron oxides and iron oxide–natural organic matter complexes

Adsorption Behavior and Mechanism of Pyrophosphate on Goethite