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Natural attapulgite (ATP) is a promising substitute for existing artificial nanozymes due to its intrinsic enzymatic activity. However, the active center of ATP's inherent enzymatic activity has not yet been revealed, which limits its further design and activity optimization. Studying the active center of mineral materials can be extremely challenging due to their complexity. Here, we demonstrated that Fe is the primary element in ATP responsible for peroxidase (POD)-like activity through theoretical speculation and experimental verification. More importantly, we found that the ratio of Fe2+/Fe3+ is responsible for the district POD-like activity of ATP from different regions with the same Fe content. Additionally, three facile strategies, including grinding, heat treatment, and acid treatment, were demonstrated to increase the relative Fe content and thus optimize the POD-like activity of ATP. Finally, ATP was used to detect the concentration of H2O2, enabling the detection of low concentrations (0.11–1.76 mM) of H2O2. This study serves as a novel reference for the future design and performance optimization of nanozymes that are based on ATP and clay minerals. [ABSTRACT FROM AUTHOR]

Photothermal superhydrophobic coatings are supposed promising to prevent ice accumulation on infrastructures but often experience significant performance degradation in real icing conditions and lack mechanical robustness. Here, we report design of robust photothermal superhydrophobic coatings with three-tier hierarchical micro-/nano-/nanostructures by deposition of nanosized MOFs on natural attapulgite nanorods, fluorination, controlled phase separation of a hydrophobic adhesive and spraying assembly. Phase separation degree and adhesive content significantly influence the coatings' properties by regulating the structural parameters and morphology. In simulated/real icing environments, the coatings simultaneously show (i) high superhydrophobicity and stable Cassie-Baxter states due to their low-surface-energy, three-tier micro-/nano-/nanostructure, (ii) excellent photothermal effect primarily due to nanosized MOFs, and (iii) good mechanical robustness by the phase-separated adhesive, reinforcement with attapulgite and the coatings' self-similar structure. Accordingly, combined with low thermal conductivity, the coatings exhibit remarkable anti-icing/frosting (e.g., no freezing in at least 150 min and almost free of frost in 25 min) and de-icing/frosting performances (e.g., fast de-icing in 12.7 min and fast de-frosting in 16.7 min) in such environments. Furthermore, we realize large-scale preparation of the coatings at reasonable costs. The coatings have great application potential for anti-icing and de-icing in the real world by efficiently using natural sunlight. Photothermal superhydrophobic coatings show poor anti-icing performance and mechanical stability in real conditions. Here, authors report on robust photothermal superhydrophobic coatings with self-similar low-surface-energy three-tier micro-/nano- /nanostructures. [ABSTRACT FROM AUTHOR]

Recently, an incinerated fibrous clay in the form of calcined attapulgite (CAT) emerges as an encouraging avenue for progress in the realm of new cementitious materials, boasting good pozzolanic activity. This study aims to examine the strength and transport features of microsilica (MS) and fly ash (FA) blended concretes made of cold-bonded coarse and fine CAT lightweight aggregates. In this regard, attapulgite pure rocks were crushed, fined, and then calcined at a specific temperature to produce a pozzolanic material. Then, a dry powder composed of 80% CAT and 20% Portland cement (PC) by weight was transformed into calcined attapulgite lightweight aggregates (CATLWAs) by cold bonding pelletization process at room temperature. Then, they were cured for 28 days. Afterward, different concrete mixtures were designed in which normal aggregate was swapped out with cold-bonded coarse and fine aggregates in different percentages up to 100%. The binary and ternary cementitious blends of PC, MS, and FA were also taken into account at various contents. Concrete samples were tested at different ages to determine their transport-related performances based on the water permeability, gas penetration, and rapid chloride permeability. The strength and microstructural properties of the samples were also measured. The results revealed that with an increase in the volume friction of coarse CATLWA up to 100% and fine CATLWA up to 25% in the mixtures, a significant reduction in the strength up to 39% was observed. Additionally, transport properties especially for the sorptivity and rapid chloride permeability were deteriorating in case of 100% volume fraction of CATLWAs. However, it was observed that these adverse effects could be eliminated by introducing binary and ternary cementitious material systems in the mixtures. [ABSTRACT FROM AUTHOR]

FeS@Fuller's Earth (FeS@FE) was synthesized by borohydride reduction in presence of dithionite with a 10% w/w iron loading. FESEM analysis reveal immobilized FeS NPs (40–100 nm) on the surface of Fuller's Earth with agglomeration. The presence of sulfur as confirmed from XPS and EDX analysis of FeS@FE. Batch adsorption study of FeS@FE for crystal violet (CV) dye adsorption in aqueous solution yielded an optimized adsorption at pH 8, adsorbent dose 0.1 g/L, with a removal of upto 80% of the dye from a 20 mg/L CV solution. The CV adsorption on FeS@FE followed a good non-linear fit for Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm with R2 > 0.95. The maximum monolayer adsorption capacity of FeS@FE was found to be 601.2 mg/g for CV with a D-R Isotherm Free energy of 141.58 kJ/mol at optimum conditions of pH 8, 100 mg/L of CV, and 0.1 g/L of adsorbent dose. The non-linear kinetic fit for CV dye adsorption on FeS@FE fitted to the pseudo-second-order (PSO) and intraparticle diffusion (IPD) models, indicating a strong chemical interaction between CV and FeS@FE. The strong adsorption of CV using FeS@FE is attributed to the Fe-OOH surface formation by FeS immobilized on FE under alkaline conditions, leading to deprotonation and electrostatic adsorption of the dye. [ABSTRACT FROM AUTHOR]

The rheological properties of drilling mud play an important role in drilling oil wells. The objective of this research is to examine the influence of cation additions on the rheological properties and filtration behavior of attapulgite obtained from Western Desert of Iraq. Mineral and chemical characteristics of attapulgite were evaluated using X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques. The rheological properties and filtration features of attapulgite were investigated by using two types of cations Na2CO3 and KCl at different concentrations: 1, 3, 5, and 7%. The results suggest that the density values exhibit stability irrespective of the addition of KCl and Na2CO3. An inverse relationship was seen between the concentration of KCl and Na2CO3 additions and the filtration rate, indicating a reduction in the filtration rate as the concentration of these additives increased. The rheological properties of attapulgite did not exhibit enhancements and failed to meet the specified criteria established by the American Petroleum Institute (API). A positive correlation was seen between the thickness of the mud and the amounts of KCl and Na2CO3 additives. [ABSTRACT FROM AUTHOR]

The specific surface area of attapulgite was significantly enhanced (from 128 to 212 m2/g) by its purification with sodium hexametaphosphate and nitric acid. Subsequently, an acid modification method was employed to prepare a coated attapulgite cordierite honeycomb with a specific surface area approximately 39 times larger than that of the bare cordierite honeycomb. SEM images showed that the surface of the cordierite was rough and uneven, with the attapulgite filling the large pores on its surface, forming a "nail-like" interaction between the coating and the carrier. After loading the catalyst, no significant mass loss was observed after 1 h of ultrasonic testing, indicating good adhesion stability of the coating. Furthermore, under test conditions of GHSV (Gas Hourly Space Velocity) = 10 000 h–1 and a toluene concentration of 1500 ppm, the prepared integrated catalyst exhibited excellent activity for the catalytic oxidation of toluene, with T50 and T90 values of 261 and 290°C, respectively, suggesting broad application prospects. [ABSTRACT FROM AUTHOR]

In this study, we developed Earth Fuller-based composites (EFBC) by incorporating varying mass fractions (2, 4, 6, and 8 wht %) of micron-sized Al2O3 and TiO2 particles. The microstructure of the prepared EFBC was analyzed using Bruker-Nova FE-SEM, operating at 5–30 kV. We investigated the thermal properties, including thermal conductivity (TC), thermal diffusivity (TD), and specific heat capacity (SHC) of the composites using a Thermal Constants Analyzer. The measurements were performed at temperatures ranging from 10 °C to 60 °C, with intervals of 10 °C. Results showed that increasing the weight percentage of Al2O3 and TiO2 in EFBC resulted in an 11% and 10% increment in thermal conductivity, respectively, at 30 °C. Interestingly, the thermal diffusivity exhibited a 9% increase with 6 wht % Al2O3 loading at 10 °C, while a 7% decrement was observed with 8 wht % TiO2 loading at 30 °C. Surprisingly, at 8 wht % Al2O3 particles, thermal diffusivity increased significantly by 195% at 30 °C. The specific heat capacity of EFBC with Al2O3 decreased by 14% at 10 °C when increasing the concentration from 2 wht % to 6 wht %, and a maximum decrease of approximately 62% was observed with 8 wht % particle loading at all temperatures. Conversely, the specific heat capacity of EFBC with TiO2 increased by approximately 10% at 10 °C when increasing particle loading from 2 wht % to 8 wht %. The highest increment of 13% in specific heat capacity for EFBC was observed at 20 °C and 40 °C. These findings provide valuable insights for potential applications of EFBC in thermal management and other fields. [ABSTRACT FROM AUTHOR]

In this study, a novel molecularly imprinted polymer (MIP) was synthesized with attapulgite (ATP) and acrylamide (AM) and ethyl methacrylate (MMA) for controlled release carrier of 5-fluorouracil (5-FU). The MIPs (PAM-PMMA) were characterized by XRD, FESEM, HRTEM, and FTIR. The drug loading and in vitro controlled release ability of MIP on 5-FU was investigated by adsorption property analysis and in vitro release analysis. MIPs (PAM-PMMA) reached a maximum drug loading of 12 mg/g and a maximum release of 80% at an ATP dosage of 0.2 g (0.4%), an initial concentration of 5-FU of 100 mg/L, and an adsorption time of 240 min. Cytotoxicity analysis showed that the maximum inhibition of cells could reach 25% at 72 h of cell culture time under the above conditions. The results showed that MIPs synthesized with ATP as the substrate and AM and MMA as the functional monomers were successfully synthesized and could be used as a drug delivery system for 5-FU. [ABSTRACT FROM AUTHOR]

In this study, a highly effective hybrid adsorbent composite based on low-cost fuller's earth (FE), aluminum silicate (AS) and chitosan (CS) was prepared using a facile method. The prepared composite was applied to adsorb lead (Pb2+) and copper (Cu2+) ions from aqueous solutions. Several analyses such as Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the composite. The adsorption efficiency of the prepared composite was investigated at different operating conditions. Moreover, the adsorption isotherm/kinetic models and adsorption thermodynamics of the composite were examined. The results showed that the pseudo-second-order kinetic model described well with the obtained data and the adsorption equilibrium can be better described by Langmuir isotherm model with maximum adsorption capacities of 305.5 and 284.2 mg/g for Pb2+ and Cu2+, respectively. The obtained data demonstrated that the prepared composite is an efficient and kinetically fast metal ion removal with high adsorption capacity and recovery efficiency. [ABSTRACT FROM AUTHOR]

Sorptive removal of cadmium (Cd) from the aqueous solutions using the easily available natural materials is an attractive method. However, the adsorption efficiencies of these materials, such as clays, are typically low. Besides, they are generally in relatively low stability and renewability, which restrict their application. Thus, modification of these materials to enhance their performance on Cd removal has gained growing attentions. Herein, the integration of calcination and ferric chloride (FeCl3) was used to modify a typical clay, i.e., attapulgite, to increase the adsorption sites, and thus to develop a robust adsorbent for Cd. Under the optimum conditions for attapulgite modification (i.e., the mass ratio of FeCl3 to attapulgite was 1:2, calcination temperature was 350 °C, and calcination time was 1.5 h) and Cd adsorption (i.e., initial pH of 6.0, adsorption temperature of 25 °C, and adsorbent dosage of 1.0 g/L), the maximum adsorption capacity of the modified attapulgite toward Cd was 149.9 mg/g. Mechanisms of surface complexation and electrostatic attraction were involved in the efficient removal of Cd. The adsorption of Cd increased with pH due to the increased electrostatic attraction. Metal cations inhibited the Cd adsorption through competing with the adsorption sites. The changes of Gibbs-free energy during the adsorption of Cd were lower than zero and decreased with temperature, suggesting the process was spontaneous and endothermic. The removal efficiency of Cd after 5 times of recycle maintained at 82% of that of the raw modified attapulgite demonstrated the stability of the adsorbent. These results suggested that the modified attapulgite is robust for Cd removal and is promising for land application. [ABSTRACT FROM AUTHOR]

The massive use of antibiotics has led to contamination of water resources, and concerns have been raised about how to treat antibiotic residues in water. In this study, a novel magnetic attapulgite composite (Fe@APT) was prepared by facile chemical precipitation. The characteristics and properties of Fe@APT were revealed by TEM, XRD, FTIR, XPS, BET, VSM, zeta potential, and batch adsorption experiments. The specific surface area of Fe@APT could reach 246.27 m2/g, which was about 1.8 times higher than that of APT. And the adsorption of tetracycline (TC) by the composite was shown by kinetics and isotherms to reveal the mechanisms, such as electrostatic attraction, physical adsorption, hydrogen bonding, π–π interaction, complexation, and electron transfer. The effects of pH and ions coexistence on the removal of TC by Fe@APT were also investigated. Specifically, the pore structure of Fe@APT was ameliorated and abundant active adsorption sites were obtained by the modification. The results showed that the maximum adsorption capacity reached 177.94 mg/g when the pH was 4, and it also exhibited good adsorption capacity under the interference of coexisting ions. Furthermore, the adsorbent displayed excellent recycling performance with easy separation. It has been proved that Fe@APT might have a potential application in antibiotic wastewater. [ABSTRACT FROM AUTHOR]

Silver-doped-titanium dioxide nanoparticles supported on Fuller’s earth, prepared by the sol-gel method, were characterized with XRD, TGA, zeta potential, SEM, EDX, TEM, XPS, photoluminescence and UV-DRS measurements. The material, Ag-TiO2-Fuller’s earth (AgTF), was tested for photocatalytic activity concerning the degradation of rhodamine B (RhB) and methylene blue (MB) in aqueous solution under visible light irradiation with pH, catalyst dosage, and dye concentration as the process variables. The degradation kinetics indicated pseudo-first-order kinetics with rate constant of (i) 0.55 min−1with 0.12 gL−1AgTF loading, 10−5 M MB at pH 9, and (ii) 0.53 min−1 with 0.08 g L−1 AgTF loading, 5 × 10−5 M RhB at pH 8. The methylene blue degradation was maximum (98.66%) for AgTF loading of 0.12 g L−1 while the maximum RhB degradation (96.34%) was attained with AgTF loading of 0.08 g L−1. With 5 × 10−6M MB concentration, the degradation achieved was 98% in 45 min and 100% in 60 min. One hundred per cent degradation of the dye, RhB (1 × 10−6 M) could be achieved in 30 min with 0.08 g L−1 AgTF at pH 8. The use of Fuller’s earth, a cheap, abundant and large surface area support, increases the adsorbability of the dye on the catalyst surface and hence promotes the degradation. The catalyst could be removed easily from the reaction mixture and reused for up to five cycles without any significant decrease in activity. Scavengers such as triethanolamine (TEOA), p-benzoquinone (BQ) and isopropyl alcohol (IPA) were utilized to get some insight into the photocatalysis mechanism. [ABSTRACT FROM AUTHOR]

Purpose: The combined contamination of As, Pb, and Cd in soil has caused serious environmental problems. In order to find a more suitable remediation method, this study used the combination of amendment materials and microorganisms to synchronously stabilize As, Pb, and Cd in compound contaminated soil. Materials and methods: The metallogenic characteristics of Lysinibacillus fusiformis were verified by SEM, XRD, FTIR, and other characterization methods; four kinds of amendment materials and microbial agent were used to carry out the comparative experiments of unitary and binary remediation respectively to stabilization soil potentially toxic element(s) (PTEs). By changing the addition amount of materials, the effects on soil physical and chemical properties, speciation transformation, and content of As, Pb, and Cd were discussed. Results: The results of comparative experiments show that the stabilization effects of loess combined with microbial agent on As and Pb are significantly improved, reaching 43.86% and 83.52%, respectively. The combination of compost sludge and microbial agent can effectively improve the stabilization effect of As, reaching 44.53%. Compost sludge can effectively reduce the content of exchangeable fraction of Pb whether used alone or combined with microorganisms. In the experiments of different addition amounts, there was no significant relationship between the addition amount and the stabilization efficiency of three PTEs when loess was added alone, but after combined with microbial agent, the stabilization efficiency of As, Pb, and Cd increased with the increase of the addition amount of loess. Conclusions: The combination of loess and MICP may be an effective method to synchronously stabilize As, Pb, and Cd in soil. Loess, attapulgite clay 1, and attapulgite clay 2 are suitable for As stabilization. Compost sludge and attapulgite clay 1 are more favorable for Pb stabilization. Loess, compost sludge, and attapulgite clay 1 promote Cd stabilization effect. Loess and compost sludge are more suitable for combination with microorganisms. [ABSTRACT FROM AUTHOR]

Calcined attapulgite (CAG) is a fibrous calcined clay with strong pozzolanic activity, which is a good candidate for the development of cementitious materials to meet the requirements of CO2 emission reduction. In this paper, the effects of CAG on the early hydration, microstructure and mechanical properties of cementitious materials were evaluated, and the influence mechanism was further explained by XRD, TG-DTG, SEM–EDS, and hydration kinetics analysis. The results show that CAG accelerates the hydration rate and promotes the early hydration process of cement by introducing additional active sites. The secondary reaction of CAG in cement consumes Portlandite (CH) in cement hydration products and dissolves Mg2+ to promote the formation of hydrotalcite. The microfiber morphology and good compatibility of CAG in cementitious materials promote the establishment of the network structure of hydration products, inhibiting microcracks and making the structure more compact. CAG promotes the strength development, and the compressive strength reaches the optimal value of 82 MPa with 6% CAG. [ABSTRACT FROM AUTHOR]

Water resources are seriously threatened by dye wastewater, and the removal of the dye molecules from the wastewater has garnered considerable interest. People have favored photocatalytic technology in recent years for the treatment of dye wastewater. In this work, attapulgite (ATP) was used as a carrier, Fe3O4 and g-C3N4 were grafted onto ATP, and the surface was then modified with polyethyleneimine (PEI) to produce photocatalyst ATP-Fe3O4-g-C3N4-PEI, which was used in Malachite green (MG) dye wastewater. The structure and surface properties of the composites were analyzed and characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray spectrum (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Uv–vis spectrum analysis, zeta potential measurement, and vibrating-sample magnetometry (VSM) analysis. The removal performance of ATP-Fe3O4-gC3N4-PEI for MG was studied, and the removal mechanism was explored and revealed. It has been shown that the heterojunction formed by Fe3O4 and g-C3N4 can inhibit the compounding of photogenerated electrons and holes, effectively improving the performance of the ATP-Fe3O4-g-C3N4-PEI. Electron paramagnetic resonance (EPR) analysis confirmed that ATP-Fe3O4-g-C3N4-PEI could generate hydroxyl radicals (·OH) and superoxide radicals (·O2-) to degrade the MG. It was believed that ATP-Fe3O4-g-C3N4-PEI could generate hydroxyl radicals (·OH) through the photocatalysis and the Fenton reaction of the composite materials. Under the action of H+, ·O2-, and ·OH, the removal rate of MG by ATP-Fe3O4-g-C3N4-PEI exceeded 98 % at an optimal condition. The intermediate products and degradation pathways of MG degradation were also inferred by LC-MS analysis. These results showed that the prepared photocatalyst has excellent degradation performance for MG and could be used in dye wastewater treatment. [ABSTRACT FROM AUTHOR]

Ceramic membranes are considered more effective for wastewater treatment applications than polymeric membranes because of their excellent resistance to thermal and chemical environments and possess high durability. To avoid the high cost of commercial ceramic membranes, recently, a significant improvement has been accomplished in developing them using low-cost alternative materials and their application in wastewater treatment. This study investigated the performance of an innovative ceramic microfiltration (MF) membrane fabricated with inexpensive Fuller's earth clay in treating the natural raw rubber (ribbed smoked sheet)-processing wastewater. The flat sheet low-cost membrane used in this study was prepared by uniaxial dry pressing route, followed by sintering at 850 °C, and it possessed 39% porosity with 0.176 µm pore size. The wastewater was treated in dead-end filtration mode at different pressures varying from 0.35 to 2 bar and observed the percentage removal of COD, turbidity, and total suspended solids (TSS). Untreated wastewater had a turbidity of 150 NTU, 1200 mg/L TSS, and 10,800 mg/L COD. At a low operating pressure of 0.35 bar, 94% removal of turbidity and total suspended solids was obtained. Also, significant COD removal of 70.4% from wastewater was obtained using the prepared low-cost MF membrane. Finally, the fouling phenomenon during the wastewater treatment was analyzed and it was concluded that it followed the cake filtration model. For future work, cross-flow filtration of wastewater using fabricated Fuller's earth clay ceramic membrane is recommended as it could pave the way forward towards commercialization and wide-scale industrial applications. [ABSTRACT FROM AUTHOR]

Aim of study was to verify the effect of temperature on the pozzolanic reactivity of thermally activated attapulgite and sepiolite samples. Activation temperatures were selected: 650, 700 and 750 °C for attapulgite and 800, 825 and 850 °C for sepiolite. Content of pozzolanic reactive SiO2 and Al2O3 after thermal treatment and the amount of Ca(OH)2 consumed in the pozzolanic reaction were measured. It should be noted that a higher activation temperature improves the reactivity of attapulgite and sepiolite. The upper limit for the increase in the pozzolanic reactivity of these materials is the formation of enstatite and the deactivation of silica. In addition to reactive decomposition products, series of minerals formed in the reactions of attapulgite and sepiolite with impurities present in them are also observed. [ABSTRACT FROM AUTHOR]

The adsorptive removal of methylene blue (MB) from aqueous solution is often executed by attapulgite (ATP) due to its unique one-dimensional nanoscale structure and low-cost, abundant, eco-friendly advantages. Another commonly used material for this job is activated carbon. In this study, a novel composite porous ceramsite was prepared by combining activated carbon and ATP clay to remove MB from an aqueous solution. The composite porous ceramsite, calcined at 450 °C (CPC-450), was characterized by SEM, FT-IR, XRD, and BET specific surface area measurements. It possessed a high specific surface area of 313.606 m2/g and exhibited superior adsorption capacity toward MB than that of raw ATP. Consequently, a 99.6% MB removal efficiency was achieved at adsorption equilibrium. Moreover, the maximum adsorption capacity of CPC-450 increased compared to the raw ATP, with a value of 50.68 mg/g, and it could be reused more than 6 times. The adsorption experiment was executed at different conditions, and the Langmuir isotherm model and pseudo-second-order kinetic equation fitted the obtained data very well. The main driving forces for the adsorption process were found to be hydrogen-bonding interaction, electrostatic attraction, and chemical association. [ABSTRACT FROM AUTHOR]

Attapulgite (ATT) is a multi-purpose nanomaterial, which can be used as a reinforcing filler for polylactic acid (PLA) and improve its barrier performance. However, due to the high content of ATT, it is easy to cause agglomeration. In this study, acetyl tributyl citrate (ATBC) was used to improve the toughness of PLA, and the plasticizer could reduce the polymer viscosity and improve the processability, which may contribute to the dispersion of ATT in PLA. The results show that a small amount of ATBC can improve the fracture elongation, crystallinity, water absorption, hydrolysis, and biodegradability of PLA. On the other hand, when ATT is added to PLA/ATBC sample by 10%, the tensile strength, and thermal degradation temperature can be greatly improved and reach the maximum value. Compared with pure PLA, the tensile strength is significantly increased by 33.4% (60.3 MPa), the elongation at break increased by 177.56%, and the thermal degradation temperature increased significantly by about 20.1 ℃. According to the scanning electron microscope and energy dispersive spectrometer, when ATT ≤ 10%, the nanofiller has excellent dispersion in the matrix, but when ATT > 10%, the nanofiller appears serious agglomeration and interfacial phase separation, which is caused by the incompatibility between PLA and ATT, so the performance of the nano composite is greatly reduced. From the results of soil burial and hydrolysis tests, the weight loss rate of PLA/ATBC samples increased with the increase of ATT nanofiller content. The influence of the internal and external tightness of the sample structure on the biodegradability was explained from the analysis results of water absorption and contact angle. The synergy of ATT and ATBC improves the comprehensive performance of PLA and increases its feasibility as a packaging material. [ABSTRACT FROM AUTHOR]

Attapulgite has been widely used in food, chemical and building materials industries as a new mineral with a unique structure and complete application. Crushing is an essential part of the preliminary treatment of attapulgite. In general, the water content of newly excavated attapulgite is often as high as 44%. Therefore, when crushing the newly excavated attapulgite, the crusher will encounter sticking tools and agglomerating, which will lower crushing efficiency and lead to motor burning or other issues. To solve the above problems, the crusher cutter was improved by combining bionics and discrete element method in this paper, and the crushing process of attapulgite was simulated numerically. The results show that: (1) The numerical simulation results are in good agreement with the literature data; (2) bionic devices can increase the disturbance of concave soil particles and make them less likely to accumulate in the front of cutting tools; (3) the bionic tool designed with crocodile teeth has low rock breaking resistance and low energy consumption; the rock-breaking efficiency increases with teeth' angle. The bionic tool can achieve the purpose of reducing viscosity and drag, and the optimized tool structure is simple and easy to realize. In addition, the introduction of bionics will help us to improve the shortcomings of traditional machinery and improve production efficiency. [ABSTRACT FROM AUTHOR]

Wastewater treatment and saltwater desalination are ways to confront water scarcity in the world. The objective of this research is the development of polysulfone (PSf) hollow fiber membranes and their respective hybrids with attapulgite clay (UBM) for effluents treatment. Membranes were produced by PSf, with 10, 15 and 20% of clay, from the phase inversion method, by the cold extrusion technique with the immersion precipitation. With the addition of attapulgite there is a reduction in the viscosity of the solutions, which may have affected the final morphology of the membranes. By X-ray diffraction of membranes, it is possible to observe a certain intercalation of the polymer among the clay lamellae for the lowest concentrations and for the highest concentrations there is a composite formation. Membranes hydrophilicity was analyzed from the contact angle, noting that the clay favor the increase of their hydrophilicity. Later, hollow fiber membranes were characterized by scanning electron microscopy and flow measurements, showing that the different clay contents modifie the membrane morphology and flow. Emulsified oil wastewater from the processing of petroleum with the permeate obtained through the flow measurements were analyzed by turbidity, and turbidity reduction results greater than 98.0% is obtained for membranes containing clay. Moreover, yields higher than 99.0% are observed in the treatment of emulsified oil wastewater from the processing of petroleum. The membrane with 20% clay presented the best results for turbidity and oil rejection. [ABSTRACT FROM AUTHOR]

In this study, the effect of the addition of natural (AT) and purified attapulgite (PAT) on the migration and transformation of phosphorus (P) in mariculture ponds sediments under static and hydrodynamic disturbance conditions was studied using sediment core incubation experiments. Whether under static or disturbance condition, the AT/PAT amendment suppressed the release of dissoluble reactive phosphorus (SRP) from sediments into the overlying seawater. The results showed that the addition of AT/PAT decreased the concentration of SRP in overlying seawater (maximum reduction rate: Rmax = 76.82%), the concentration of SRP in pore seawater (Rmax = 62.62%) and the diffusion flux of SRP at the sediment-water interface (SWI) (Rmax = 34.22%). Furthermore, adding AT/PAT to the top sediments (0–1 cm) not only reduces the content of Mobile-P in the added layer, but also reduces Mobile-P in the sediments (1–2 cm) below the added layer. In addition, under the condition of disturbance, the reduction rate of Mobile-P in the PAT added layer (42.16%) was higher than that of AT (21.12%). The reduction of Mobile-P in the top sediment, SRP in the pore seawater as well as the diffusion flux of SRP from the pore seawater to the overlying seawater across the SWI played a key role in the control of SRP release from sediments to the overlying seawater by the AT/PAT amendment. Results of this work indicate that the AT and PAT are very promising amendment for the control of SRP release from mariculture ponds sediments under static and hydrodynamic disturbance conditions. [ABSTRACT FROM AUTHOR]

A nano-ZnO semiconductor material loaded with mineral attapulgite (ATP) photocatalyst has been investigated. Using ATP as a carrier, a variety of various mixtures of ZnO/ATP composites was synthesized. A scanning electron microscope (SEM), X-ray diffractometry (XRD), and UV-Vis spectrophotometer (UV-Vis) were used to examine the morphology, synergistic effects, and photocatalytic properties of ZnO/ATP nanocomposites. The target pollutant for photocatalytic degradation is methylene blue solution. When ATP is mixed with pure ZnO, the degrading performance of composite nanomaterials in methylene blue solution is considerably enhanced. The degree of methylene blue degradation increases as the amount of ATP in the composite grows, and the degradation rate of ZnO/40% ATP can reach 96% in 45 min under solar light illumination. The amount of ATP in the system is excessive, and the adsorption effect is visible. The optimal composite ratio was determined to be ZnO/30% ATP. After discovering the ideal composite ratio and synergy of ZnO/ATP, g-C3N4 was compounded in the aforesaid system, dramatically increasing the composite's photocatalytic activity. At 45 min, the degradation rate of methylene blue reaches 97%. The absorption range and intensity of ternary composites increased, and the photogenerated electron-hole recombination rate decreases significantly. The reaction rate constant increases from 0.033 to 0.069 min−1. SEM revealed rod-like attapulgite particles packed with tiny zinc oxide particles and a moderate layered structure of C3N4. The XRD pattern indicated that C3N4's crystallinity is poor and ZnO's peak intensity is excessively high, masking the composite material's distinctive peaks. The degradation rate of g-C3N4/ZnO/30% ATP to methylene blue was found to be 91.5% after 5 cycles. [ABSTRACT FROM AUTHOR]

Fenton-advanced oxidation process has a good effect on the degradation of toxic and harmful substances in industrial wastewater. However, homogeneous Fenton has the problems of serious iron sludge pollution and high catalyst cost in practical application. To search for a cheap, stable Fe-based catalyst with good performance has become an urgent task in the field of heterogeneous Fenton. Attapulgite is a natural clay mineral with a porous surface and special crystal structure, which is suitable for a catalyst carrier. In this study, the granulation conditions and Fe3+ loading conditions of attapulgite were investigated, the effects of two preparation sequences on the degradation of Rhodamine-B were compared, and the best heterogeneous Fenton granular catalyst was selected. In the process of granulation, the adsorption and decolorization effects on Rhodamine-B of particles were the best when the additive dosage ratios were AlCl3 1%, Fe2O3 3%, and SiO2 3% respectively. When impregnation concentration, temperature, time and ratio of liquid to solid were 1.6 mol/L, 80 ℃, 4 h, and 20:1, respectively, the optimum Fe3+ loading condition was obtained, and the method of granulating first had a better removal effect on dye. Subsequently, the structural characteristics, phase changes and iron distribution of attapulgite before and after loading Fe3+ were characterized. In the process of exploring the optimal degradation conditions, the results showed that the degradation of dye remained above 98% after the catalyst was reused for 5 times, indicating that the catalyst can be a promising eco-friendly material for refractory wastewater treatment. [ABSTRACT FROM AUTHOR]

Coagulation/flocculation is one of the most widely used and cost-effective pretreatment methods for improving the dewaterability of sludge. In this study, a cationic modified starch-based flocculant (St-CTA) in conjunction with a popular clay, attapulgite (ATP), was used for the conditioning of waste-activated sludge. The dewatering properties, including the filter cake moisture content, filtration specific resistance, capillary suction time, filtration rate and compressibility coefficient, were measured and compared by varying the doses of St-CTA and ATP. By combination of the apparent dewatering performance and the changes in the contents and distributions of the extracellular polymeric substance (EPS) fractions and components, sludge flocs, and microstructures of sludge cakes, the dewatering mechanisms were discussed in detail. St-CTA in conjunction with ATP can exhibit an enhanced dewaterability of sludge and the water content in final sludge cake can be stably reduced below 80% owing to the synergistic effects of St-CTA and ATP. In addition to the efficient charge neutralization of St-CTA, ATP not only acts as a skeleton builder in the sludge dewatering process which makes the sludge flocs more compact and improves the filterability and permeability, but also tightly interacts with the proteins in EPS of the sludge which reduces the protein content and further enhances the dewatering effect. This study provides an economical, green, and effective way to further improve the dewaterability of sludge. [ABSTRACT FROM AUTHOR]

Recycling dysprosium (Dy) from an environment can not only alleviate the industrial crisis, but also reduce the ecological pollution caused by Dy(III). The cost of the materials used to adsorb rare earth ions is generally high, which is not conducive to the wide application of adsorbents in the rare earth industry. Herein, we developed an inexpensive adsorbent based on a three-dimensional network structure consisting of carboxylated bacterial cellulose, attapulgite, and gelatin to replace high-priced adsorbents. A low-cost and green I-APT-GT-OBC aerogel was prepared by a simple freeze-drying process. To test the adsorption properties of the composite aerogel, we carried out a series of adsorption experiments. The results showed that the saturated adsorption capacity of Dy(III) by the imprinted aerogel was 48.762 mg g−1 when the pH value was 5.0, and the adsorption process was spontaneous, endothermic and entropy increasing. In the competitive adsorption experiment, the Kd value of I-APT-GT-OBC for Dy(III) was 4084.40 mL g−1, which was much higher than that of other aerogels, showing excellent selective adsorption. In conclusion, I-APT-GT-OBC is expected to be a low-cost adsorbent that can efficiently adsorb Dy(III) in water. [ABSTRACT FROM AUTHOR]

Magnetite/zirconium-comodified attapulgite (Fe/ZrATP) acting as a novel phosphorus (P) sorbent was synthesized, characterized and applied to control P in an aquatic environment. Batch experiments demonstrated that at an adsorption dose of 0.2 g, 97.8% of the phosphate was rapidly sequestered from aqueous solution within 24 h, and the composite reached a maximal sorption capacity of 3 mg/g. The adsorption performance of the adsorbent Fe/ZrATP was minimally affected by changes in the initial pH (pH = 2–11). In addition, Fe/ZrATP presented excellent selectivity for phosphate when coexisting ions that often occur in water bodies were present; the solution ionic strength exerted little influence on phosphate sorption behavior. Adsorption and desorption experiments indicated that the removal of phosphate was mainly due to adsorption. The Fe/ZrATP adsorption isotherm was fitted to the Freundlich adsorption model. Moreover, the composite demonstrated excellent recyclability performance. The P adsorption mechanism of Fe/ZrATP involves electrostatic interactions, ligand exchange and surface precipitation. Our findings indicated that the separable Fe/ZrATP demonstrated high efficiency and sustainable phosphate removal, which is promising in phosphate removal and recovery applications [ABSTRACT FROM AUTHOR]

The effects of attapulgite (ATP) addition (0, 1, 3, 5 and 7 wt %) on the microstructure, chemical composition, thermal stability, physical properties, mechanical properties, water absorption and abrasive wear resistance of walnut shell (WS) filled polyvinyl chloride (PVC) composites were studied. ATP was blended with WS powder, and the WS/ATP/PVC composites were prepared by melt blending extrusion using a single screw extruder. The performance test results of the composites showed that, properties of the composites were improved after the addition of ATP when compared to the composites without ATP, although the chemical structure of the composites did not change significantly. The composites with 3% ATP have the best thermal stability and wear resistance, as well as the lowest water absorption. The tensile strength, bending strength, hardness and density increased by 31%, 16%, 10% and 1% respectively. However, the composite has the highest impact strength after adding 1% ATP, which was 11% higher than without ATP. The results indicate that ATP has the potential to improve the characteristics of biomass composites in a simpler and more environmentally friendly method. [ABSTRACT FROM AUTHOR]

A novel hybrid nanocomposite (HNC) was prepared by in situ microwave-mediated polymerization of 2-hydroxyethylmethacrylate with microfibrillated sugarcane bagasse, microfibrillated chitin and Fullers' earth. N,N′-Methylenebisacrylamide as a cross-linker and potassium persulfate as initiator were used as additives. Structural characterization of HNC was performed by FTIR spectroscopy, scanning electron microscopy and powder X-ray diffractometry. Water absorption experiments revealed the superabsorbent behaviour of HNC, and it can absorb water over a long period of time. The results of swelling–deswelling cycles revealed that HNC exhibits high recyclability with increased percent swelling after each cycle. Swelling percent reached 2000% in 24 h and 9000% in 10 d. However, equilibrium was not attained even after this duration. Antimicrobial studies were conducted to evaluate the microbial decomposition behaviour of HNC. While HNC is based on biopolymers (microfibrillated sugarcane bagasse and chitin), it was found to exhibit resistance towards microbial decomposition even after exposure for several months under ambient conditions. However, it was found to undergo degradation in moist garden soil in 2 months. Adsorption performance of HNC for Pb(II) ions was investigated in aqueous solutions at 291, 296 and 303 K at pH 7 using Langmuir, Freundlich, Temkin and Dubinin–Kaganer–Radushkevich models of adsorption. Data were found to fit well with the Langmuir model indicating the primarily physical nature of adsorption. The results of adsorption kinetics were found to be in good agreement with the pseudo-second-order model. Overall, HNC was found to exhibit high adsorption capacity for Pb(II) ions in aqueous solutions with a maximum adsorption capacity of 500 mg/g at 303 K. More than 90% Pb(II) ions could be readily recovered by soaking the Pb(II)-loaded HNC in dilute acetic acid. [ABSTRACT FROM AUTHOR]

Metal-salt-modified clay minerals are widely used for endogenous phosphorus control in eutrophic lakes because of its high efficiency of P adsorption, but changes in water quality due to material dosing limit their practical remediation performance. In this study, lanthanum was embedded in thermally-treated calcium-rich attapulgite (TCAP) to strengthen its P uptake ability, and a novel and efficient phosphorus fixation material lanthanum-modified attapulgite (La-TCAP) was synthesized. Batch adsorption experiment indicated that the maximum P sorption capacity of La-TCAP can reach as high as 9.777 mg P/g, which was more than twice that of TCAP. The P removal rate of La-TCAP was maintained between 55.62% and 68% at 4–10 pH. La-TCAP exhibits strong resistance to interfering ions including SO42−, NO3−, Cl−, and HCO3− during phosphorus adsorption. The characterization analysis of La-TCAP showed that the adsorption of phosphate on La-TCAP was mainly based on the surface complexation reaction. Sediment P immobilization studies demonstrated that the coverage of La-TCAP contributed the P recession of 30% to 58.8% in overlying water during the aerobic and anaerobic incubation. Meanwhile, other water quality indicators in the overlying water had hardly changed. The content of Mobile-P in the surface sediments (0–4 cm) was drastically reduced, while the content of Al-P and Ca-P was greatly increased. The results of this study suggest that La-TCAP is a promising P immobilization material for sediment P control in urban eutrophic lake. [ABSTRACT FROM AUTHOR]

Herein, polyvinyl alcohol-carboxymethyl cellulose (PVA-CMC) composite hydrogel membranes were prepared using solution-casting method, where citric acid (CA) was added as crosslinker in different ratios of (7, 10 and12 wt%). Attapulgite clay extracted from Northwestern Desert of Borg El-Arab, Egypt; was incorporated as nanofiller (1, 2, 4, and 5 wt%) into membranes for improving their mechanical/ thermal stability. Results revealed that, physicochemical properties of membranes e.g. swelling%, tensile strength and morphology of membranes affected significantly by different clay concentrations and citric acid crosslinker. Also, attapulgite clay with concentration 1 (wt%) enhanced mechanical strength of composite membranes, compared to other clay concentrations. Furthermore, protein adsorption %, hydrolytic degradation, hemolysis (%) and antimicrobial activity significantly affected by clay contents and CA concentrations. Four bacterial pathogens e.g. Candida albicans, Escherichia coli, Klebsiella pneumoniae, and Bacillus cereus were used for testing antimicrobial activity of prepared membranes. Results referred to increasing of clay contents led to a high hemolysis %; however, increasing CA concentration significantly reduced hemolysis %. Meanwhile, membranes with low clay contents offered the most effective resistance against tested microbes. These findings are referring to the ability of using PVA-CMC-attapulgite composite membranes crosslinked by CA as good candidate of biomaterials for dermal wound dressings. [ABSTRACT FROM AUTHOR]

Aim of this work was to synthesize mercapto-modified attapulgite (ATP-SH) and explore the effectiveness and mechanism of ATP-SH on the remediation of Cd-contaminated soil. The ATP-SH was applied to the remediation of cadmium contaminated soil with a concentration of 5.48 mg/kg through pot rice experiment. The changes of soil physicochemical properties, Cd content in rice and straw, available Cd, and different speciation of Cd in soil were studied after the addition of ATP-SH. Some methods, such as XRD, FTIR, and XPS, confirmed successfully grafting of the mercapto. The addition of ATP-SH has little effect on the major physicochemical properties of soil. Compared to the blank group (CK), with the increase of ATP-SH dosage, the available Cd content in soil and the Cd content in rice and straw decrease significantly, and the maximum reduction rates are 73.1%, 92.6%, and 85.7%, respectively; the exchangeable Cd (EX-Cd) and carbonate bound Cd (CAR-Cd) in soil decrease significantly, while Fe/Mn oxide bound Cd (FMO-Cd) and strong organic bound Cd (SO-Cd) increase significantly. Combined with a large number of previous conclusions, we believe that the Si-2p and Al-2p electron clouds in ATP-SH transfer and change the electronic properties of iron, thus increasing the adsorption of Cd on its surface, and then coating to form FMO-Cd, and there are a large number of sulfhydryl and hydroxyl on the surface of the material, which have strong bonding effect on Cd to form SO-Cd. The application of ATP-SH could effectively reduce the content of Cd in straw and rice by the synergistic effect of ATP, S, and Fe rather than increasing soil pH to stabilize heavy metals. It is an efficient remediation agent for Cd-contaminated paddy soil with a good practical application prospect. [ABSTRACT FROM AUTHOR]

The pristine attapulgite (Atta) was pretreated by thermal and acid activation process in order to improve the loading capacity of phase change material (PCM). A series of pretreated Atta-based composite PCM was prepared combined with different kind of fatty acids. The XRD, FT-IR and XRF results shown that the pretreated process increased the purity of Atta as well as the SEM micrographs and BET results indicated that the porosity of Atta slightly increased after pretreating. What's more, XRD and FT-IR results of the composites PCMs shown good chemical compatibility. DSC results indicated that the composite PCMs of AH-Atta/Lauric acid (LA), AH-Atta/Palmitic acid (SA) and AH-Atta/Docosanoic acid (DA) melted at 42.8 °C, 1.4 °C and 75.2 °C with the latent heat of 94.6 J g−1, 107.5 J g−1 and 84.6 J g−1 at the maximum loading of 51.0%, 50.8% and 51.3%, respectively. In addition, TGA results and 200 thermal cycles test results proved the good thermal stability and reliability of the samples. Based all above results, the prepared composite PCMs have good potential application in energy conservation buildings at different function temperature. [ABSTRACT FROM AUTHOR]

Attapulgite (ABSO-PRO L-16) was modified using a coupling agents, 3-aminopropyltriethoxysilane (APTES) and 3-mercaptopropyl-trimethoxysilane (MPTMS). The samples characterized by Fourier Transform Infrared Spectroscopy (FTIR/ATR), Elemental analysis CHNS, Mastersizer analysis and Thermogravimetric analysis (TGA). FTIR spectrums patterns revealed that a new Si–O–Si bond formed after modification of attapulgite with APTES. This modification methods allows for the improvement of the chemical compatibility of attapulgite with specific resins for application in heat-resistant silicone pressure-sensitive adhesives. New self-adhesive tapes based on attapulgite-modified silicone resins have been obtained. The new self-adhesive materials showed increased thermal resistance while maintaining good self-adhesive properties. [ABSTRACT FROM AUTHOR]

In this research, the sorption characteristics and mechanism of phosphate on zirconium-modified attapulgite (Zr-ATP), iron-modified attapulgite (Fe-ATP), and zirconium/iron co-modified attapulgite (Zr/Fe-ATP) prepared by a simple impregnation method were studied, and the impacts of Zr-ATP, Fe-ATP, and Zr/Fe-ATP amendment and capping on the migration of phosphorus (P) from sediments to overlying waters were investigated. The results showed that Zr-ATP and Zr/Fe-ATP possessed stronger adsorption ability for phosphate in aqueous solution than Fe-ATP. The ligand replacement of the hydroxyl group with the phosphate anion to form the inner-sphere phosphate complex played a crucial role in the adsorption process of phosphate on Zr-ATP, Fe-ATP, and Zr/Fe-ATP. Most of the phosphate ions bound by Zr-ATP and Zr/Fe-ATP were in the form of caustic soda solution-extractable inorganic P (NaOH-IP) and residual P (Res-P), and it is hard for these P species to be re-released into water under the circumstances of reducing environment and normal pH (5–9). The ratio of mobile P to total P of Fe-ATP loaded with phosphate was much higher than those of Zr-ATP and Zr/Fe-ATP loaded with phosphate, indicating that Fe-ATP-bound phosphate has a higher re-releasing risk than Zr-ATP-bound and Zr/Fe-ATP-bound phosphate. Zr-ATP, Fe-ATP, and Zr/Fe-ATP amendment all can reduce the releasing risk of P from sediments to overlying waters. The amendment of sediment with Zr-ATP and Zr/Fe-ATP can both induce the conversion of redox-sensitive P (BD-P) to NaOH-IP and Res-P in the sediment, making the phosphorus in the sediment more stable. However, the amendment of sediment with Fe-ATP can only induce the conversion of HCl-P to NaOH-IP in the sediment and had a negligible effect on the inorganic P activity in the sediment. Zr-ATP, Fe-ATP, and Zr/Fe-ATP capping all can reduce the risk of P release from sediment into the overlying water, and Zr-ATP and Zr/Fe-ATP capping had a better reduction efficiency of internal P liberation to the overlying water than Fe-ATP capping. Zr-ATP, Fe-ATP, and Zr/Fe-ATP capping all can give rise to the reduction of pore water SRP and diffusive gradient in thin-film (DGT)-labile P in the upper sediment. This is beneficial to the control of P releasing from sediment into the overlying water by the Zr-ATP, Fe-ATP, and Zr/Fe-ATP capping. The findings of this work suggest that Zr-ATP and Zr/Fe-ATP are promising active capping or amendment materials for internal P loading management in surface water bodies. [ABSTRACT FROM AUTHOR]

Attapulgite (ATP) is a low-cost hydrated clay mineral of aluminum and magnesium and can be used for the preparation of linear low-density polyethylene (LLDPE) nanocomposites. However, the ATP contains accessory minerals that can harm their performance and hinder their polymer interaction. Then, a purification process of this clay mineral is necessary to raise the interactions between ATP and LLDPE. Furthermore, the non-polar nature of LLDPE can also hinder these interactions. One way to improve these interactions is the surface modification of ATP. In this way, the ATP was modified using aminosilane (3-aminopropyl) triethoxysilane (APTES). Raw ATP (ATPr), purified ATP (ATPp), and silanized ATP (ATPs) were characterized, and LLDPE/ATP nanocomposites with 3 and 5 wt% of ATPr, ATPp, and ATPs were prepared by extrusion. The nanocomposites were characterized by scanning electron microscopy (SEM), mechanical properties (tensile tests, Shore D hardness, and impact strength), and X-ray diffraction. APTES was grafted onto the clay surface. The APTES did not modify the crystal structure of ATP and, in addition, it improved the mechanical properties of LLDPE/ATPs nanocomposites. The addition of 5 wt% of ATPs increases the tensile strength, elastic modulus, and Shore D hardness, in addition to improving the dispersion of nanoclay in the polymer matrix. [ABSTRACT FROM AUTHOR]

The porous material MOF-199 with a large specific surface area is widely used in the field of adsorption, but the single MOF material is not stable enough and the adsorption performance needs to be improved, so MOFs materials are often modified by combining with other materials. The composite material Fe3O4-ATP/MOF-199 (FAM) was prepared by solvothermal method combined with MOF-199, attapulgite (ATP) and Fe3O4. It was used in the static adsorption experiment of model oil to study the desulfurization performance, including the influence of external conditions such as adsorption time, temperature and the mass ratio of model oil to adsorbent on adsorption capacity. The structure and morphology of the adsorbent were characterized by XRD, FT-IR, SEM, VSM and BET. The experimental results show that the doping of attapulgite reduces the particle size of magnetic MOF-199 and makes the adsorbate closer to the active center of the adsorbent so as to improve the adsorption efficiency. [ABSTRACT FROM AUTHOR]

Mercury pollution has become one of the most concerned environmental issues in the world because of its high toxicity, non-degradability, and bioaccumulation. Attapulgite adsorbents modified by magnetic manganese-copper (MnxCuy-MATP) were fabricated by co-precipitation and ultrasonic impregnation method, aiming at removing Hg0 from coal-fired flue gas. BET, SEM, XRD, VSM, and XPS were used to systematically explore the physical and chemical properties of the adsorbents, the effects of manganese and copper additions, reaction temperature, and various components in the flue gas on the efficiency of Hg0 removal were investigated. Mn8Cu5-MATP exhibited the optimal properties, and excessive copper loadings led to the aggregation of the active components. The efficiency of mercury removal can be effectively improved by NO and HCl regardless of the absence and presence of O2, because the NO+, NO3, NO2, and Cl* produced during the reaction can promote the adsorption and oxidation of Hg0. SO2 and H2O inhibited the oxidation of Hg0 because of the competitive adsorption at the active sites, while a large amount of sulfite and sulfate were formed to block the pores. However, the introduction of copper caused the sample to obtain SO2 resistance, which resulted in a mercury removal efficiency of 84.3% even under 1500 ppm SO2. In addition, after 5 cycles of adsorption and regeneration, Mn8Cu5-MATP can still maintain excellent Hg0 removal ability. The fabricated adsorbent can save the actual production cost and effectively improve the mercury removal efficiency in sulfur-containing flue gas. [ABSTRACT FROM AUTHOR]

To solve the harm caused by hazardous chromium-containing sludge (CCS, chromium-containing sludge) waste to humans and the environment, this study used attapulgite to strengthen alkali slag to prepare cementitious materials to solidify/stabilize CCS. Single-factor and orthogonal experiments were used to optimize the preparation parameters of alkali slag cementitious materials. The compressive strength, heavy metal leaching toxicity, and microscopic characterization of a CCS solidified body were tested to investigate the solidification effect and mechanism of CCS formation. The best attapulgite content was 4%; the solidified body after the treatment of chromium-containing sludge had a good performance of heavy metal leaching and mechanical properties. The addition of attapulgite enhanced the compressive strength. Compared with the original CCS, the leaching concentration of heavy metals in the solidified body was significantly reduced. Among them, the solidified efficiency of chromium is stable above 90%. The changes in the results of XRD and FTIR for each component were studied. It indicated that the solidified body may solidify/stabilize heavy metals through physical encapsulation of the amorphous form and chemical immobilization. This research recognized the use of waste to treat waste, realized the combined effect of solidification/adsorption, and indicated the possibility of application of attapulgite and its solidified products in construction. [ABSTRACT FROM AUTHOR]

The present paper studied the effects of calcination temperatures (200–800 °C) on the appearance, mineral composition, and active SiO2 content in attapulgite and investigated the effects of attapulgite before and after calcination on the chemically bonded water content, the degree of reaction of cement paste, and the mechanical properties such as the flexural strength, compressive strength, and splitting-tensile strength of cement mortar. The results indicate that the calcination temperature changes the mineral composition of attapulgite, thereby affecting the hydration activity of cement-based materials. The attapulgite calcined at 500 °C (AT500) has the best enhancement on the hydration activity of cement-based materials. The calcination at 500 °C is most beneficial to the dissolution of SiO2, and the content of SiO2 reaches 20.96%. The contents of chemically bonded water in the samples incorporated with calcined attapulgite reduced and that of the samples incorporated with AT500 at 28 d is the same as that of the control group. The reaction degree of AT500 is 78.61% at 28 days. Calcined attapulgite clay can reduce the energy consumption of the cement industry and promote the sustainable development of attapulgite clay. [ABSTRACT FROM AUTHOR]

Heavy metal ions have become a major problem that seriously affects the environment, ecology, and human health with the development of industrialization. Herein, the amino-grafted attapulgite/graphene oxide (A-ATP/GO) nanocomposites were synthesized for Pb(II) removal. The influencing factors including the ratio of the components, pH value, adsorption time, initial concentration of Pb(II) solution, and adsorbent amount were investigated to achieve the optimal adsorption performance. The as-prepared A-ATP/GO were used in Pb(II) solution (150 mg/L, 30 mL, pH = 5) for Pb(II) adsorption, which exhibited a great adsorption ability of 146.97 mg/g for Pb(II). The adsorption kinetic model and isotherms model were applied to investigate the adsorption mechanism of Pb(II) on A-ATP/GO. The A-ATP/GO composite could still maintain an original adsorption of 79.85% after 5 consecutive times, exhibiting the good reproducibility. It was believed that our results could shed light on the design and fabrication of low-cost graphene-based composite adsorbents for high-efficient Pb(II) removal. [ABSTRACT FROM AUTHOR]

Steam reforming (SR) of bio-oil has been considered as one of the promising methods for hydrogen production. In this paper, cerium modified Ni/Attapulgite (ATP) catalysts were successfully synthesized by traditional chemical precipitation method and utilized for SR of various bio-oil derived oxygenated model compounds. The effect of Ce content on the structural properties of Ni/ATP was investigated by ICP-OES, N2 adsorption–desorption, XRD, H2-TPR and HRTEM characterizations. The results exhibited that 10Ce–Ni/ATP catalyst had the strongest metal-support interaction and highly dispersion of Ni species with smallest particle size of 6.21 nm. Therefore, it presented the maximum ethanol conversion of 97.21% and H2 yield of 83.15% at relative lower reaction temperature 500 °C during 4 h of SR of ethanol (SRE). In addition, it unfolded promising performance for SR of acetic acid (SRAA) and acetone (SRA). Furthermore, the influence of different oxygenates on the amount and nature of carbon deposits in used 10Ce–Ni/ATP catalyst was revealed by TG and Raman analyses. It found that the types of feedstock significantly affected the carbon species and amount and the formation of graphic layers around the Ni metal sites was the mainly factor for rapid deactivation of 10Ce–Ni/ATP during 4 h of SRA reaction. [ABSTRACT FROM AUTHOR]

In the present study, attapulgite (ATP)-maintained nanoscale zero-valent iron (nZVI) at different Fe/ATP mass ratios (1:3 and 1:5) was synthesized by liquid phase reduction for its use to remove chromium Cr(VI) in aqueous solution. The morphology, crystalline structure, chemical composition, and valent states of these nZVI/ATP composites were evaluated before and after the reaction. Obtained characterization data indicated an effective dispersion of nZVI on ATP surface, preventing the agglomeration of nZVI particles. Results showed that the introduction of ATP has higher Cr(VI) removal efficacy as compared to the bare nZVI or ATP. At Cr(VI) initial level of 40 mg L−1, the remediation efficacy of Cr(VI) in nZVI/ATP(1:3) reached 91.63%, which was substantially higher than that of bare nZVI (48.68%) and ATP (2.52%). Co-precipitation and reduction of Cr-containing metal deposited onto nZVI/ATP were found as the major reaction mechanisms. At lower initial level of Cr(VI) (20 mg L−1), the reduction was the dominant process where Fe(II) was the major form of iron in the reaction product. However, adsorption was the major mechanism at higher initial level of Cr(VI) (100 mg L−1) whereas the reaction product mainly comprised the ferric form of iron (Fe(III). The main reaction product was the FeCr2O4 under low or high Cr(VI) concentrations which can reduce the risk of secondary pollution because of its high stability. [ABSTRACT FROM AUTHOR]

B Background: b Access to fentanyl and fentanyl analogs has increased in the USA and has been increasingly identified in forensic laboratory testing for driving while under the influence of drugs (DUID) investigations. Formal analysis of fentanyl and norfentanyl ratios or inclusion of acetylfentanyl may have provided additional context of recency of exposure. B Background: b Many chemical warfare agents (CWAs) and industrial chemicals exist with significant potential for toxic effects following contact with skin. Keywords: Skin decontamination; Glucagon; Flumazenil; Naloxone; Fentanyl; Helium EN Skin decontamination Glucagon Flumazenil Naloxone Fentanyl Helium 58 62 5 01/17/22 20220101 NES 220101 B Article #1: b Feschuk AM, Law RM, Maibach HI. [Extracted from the article]

A series of CeO2–WO3/20%ATP-TiO2 catalysts were synthesized, of which attapulgite (ATP) was modified by different methods. Notably, after ATP was dissociated and acidified, the catalyst synthesized by the impregnation method exhibited satisfactory performance for selective catalytic reduction (SCR) NOx with NH3. In more detail, the NO conversion could reach to 88% at 240 °C and maintain above 93% in the temperature range of 280–400 °C. Subsequently, the NO conversion of the best catalyst could keep above 80% after introducing H2O and SO2, so this catalyst also had strong tolerance to H2O and SO2 performance. Besides, the results of XRD, XPS, TEM characterizations suggested that the high dispersion of active species cerium and tungsten on the surface of ATP, which played an important role in improving the SCR performance of the catalyst. In short, the surface dissociation and surface acidification of a small amount of ATP carrier can improve the catalyst catalytic performance, so it will have a broad application prospect in SCR reaction. [ABSTRACT FROM AUTHOR]

A series of CeO2–WO3/20%ATP-TiO2 catalysts were synthesized, of which attapulgite (ATP) was modified by different methods. Notably, after ATP was dissociated and acidified, the catalyst synthesized by the impregnation method exhibited satisfactory performance for selective catalytic reduction (SCR) NOx with NH3. In more detail, the NO conversion could reach to 88% at 240 °C and maintain above 93% in the temperature range of 280–400 °C. Subsequently, the NO conversion of the best catalyst could keep above 80% after introducing H2O and SO2, so this catalyst also had strong tolerance to H2O and SO2 performance. Besides, the results of XRD, XPS, TEM characterizations suggested that the high dispersion of active species cerium and tungsten on the surface of ATP, which played an important role in improving the SCR performance of the catalyst. In short, the surface dissociation and surface acidification of a small amount of ATP carrier can improve the catalyst catalytic performance, so it will have a broad application prospect in SCR reaction. [ABSTRACT FROM AUTHOR]

This work focused on using attapulgite and chitosan as raw materials to improve the adsorption capacity of Cd2+ from the aqueous phase by optimizing the preparation experimental parameters. The modification parameters (attapulgite-chitosan mass ratio, calcination temperature, and time) were specifically studied and optimized. The results indicated that the mass ratio of attapulgite to chitosan was 1:4, the calcination temperature was 300 °C, and the calcination time was 1 h. Both raw and functionalized attapulgite samples were characterized by nitrogen adsorption-desorption isotherms at 77 K, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and zeta potential analysis. A series of adsorption experiments showed that the pseudo-second-order kinetic model and Langmuir adsorption isotherm better corresponded with the adsorption characteristics of the newly prepared adsorbent, and the maximum adsorption amount of Cd2+ was 109.30 mg/g. Moreover, the effects of the pH value and coexisting cations on the Cd2+ adsorption in aqueous solution were investigated. Adsorption mechanism of Cd2+ on adsorbent might attribute to complexation, ion exchange reaction, and self-polarization. [ABSTRACT FROM AUTHOR]

An efficient composite was constructed based on aminated chitosan (NH2Cs), attapulgite (ATP) clay and magnetic Fe3O4 for adsorptive removal of Cr(VI) ions. The as-fabricated ATP@Fe3O4-NH2Cs composite was characterized by Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analyzer (TGA), Scanning Electron Microscope (SEM), Zeta potential (ZP), Vibrating Sample Magnetometer (VSM), Brunauer–Emmett–Teller method (BET) and X-ray photoelectron spectroscope (XPS). A significant improve in the adsorption profile was established at pH 2 in the order of ATP@Fe3O4-NH2Cs(1:3) > ATP@Fe3O4-NH2Cs(1:1) > ATP@Fe3O4-NH2Cs(3:1) > Fe3O4-NH2Cs > ATP. The maximum removal (%) of Cr(VI) exceeded 94% within a short equilibrium time of 60 min. The adsorption process obeyed the pseudo 2nd order and followed the Langmuir isotherm model with a maximum monolayer adsorption capacity of 294.12 mg/g. In addition, thermodynamics studies elucidated that the adsorption process was spontaneous, randomness and endothermic process. Interestingly, the developed adsorbent retained respectable adsorption properties with acceptable removal efficiency exceeded 58% after ten sequential cycles of reuse. Besides, the results hypothesize that the adsorption process occurs via electrostatic interactions, reduction of Cr(VI) to Cr(III) and ion-exchanging. These findings substantiate that the ATP@Fe3O4-NH2Cs composite could be effectively applied as a reusable adsorbent for removing of Cr(VI) ions from aqueous solutions. [ABSTRACT FROM AUTHOR]

This study investigates the performance of support vector machine (SVM), multivariate adaptive regression spline (MARS), and random forest (RF) models for predicting the lead (Pb) adsorption by attapulgite clay. Models are constructed using batch stochastic data of heavy metal (HM) concentrations under different physicochemical conditions. Implementation of auto-hyper-parameter tuning using grid-search approach and comparative analysis is performed against the benchmark artificial intelligence (AI) models. Models are constructed based on Pb concentration (IC), the dosage of attapulgite clay (dose), contact time (CT), pH, and NaNO3 (SN). Principle component analysis (PCA) and correlation analysis (CA) methods are integrated to assess the importance of the applied predictors and their relationship with the target. Research findings approved the potential of the grid-RF model as a marginal superior predictive model against the grid-SVM in terms of MAE, i.e., 3.29 and 3.34, respectively; moreover, the md scored the same, i.e., 0.93, which reveals the potential predictability for both. Nonetheless, grid-MARS and standalone MARS models remained likewise in their predictability. IC parameter demonstrated the highest influential among all the predictors with the highest value of importance in the case of all three evaluators. The solution pH and dose stands together with marginal differences in case of PCA method; however, solution pH and CT appeared with similarity impact using the PCA method. [ABSTRACT FROM AUTHOR]

In this study, a novel method which involved in-tube solid-phase microextraction (SPME) using an attapulgite (ATP) nanoparticles–based hydrophobic monolithic column was successfully developed. It was coupled with high-performance liquid chromatography-ultraviolet detection for the determination of three phosphodiesterase-5 (PDE-5) inhibitors, including thiosildenafil, pseudovardenafil, and norneosildenafil, in functional foods. The monolithic column was prepared by one-step polymerization, using 3-trimethoxysilylpropyl methacrylate–modified ATP nanoparticles and 1-butyl-3-vinylimidazolium bromide (VBIMBr) as the functional monomers, and ethylene glycol dimethacrylate (EDMA) as the cross-linker. The obtained poly(ATP-VBIMBr-EDMA) monolith was characterized by scanning electron microscopy equipped with energy-dispersive analysis of X-ray, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction. The adsorption capacity, up to 2.00 μg/cm calculated by the Langmuir isotherm model, was about six times that of the poly(VBIMBr-EDMA) monolith. Crucial factors affecting the extraction efficiency, including sample solvent, elution solvent, flow rates of sampling loading and elution, sample loading volume, and elution volume, were investigated in details. Under the optimal in-tube SPME conditions, the proposed method showed good reproducibility with run-to-run, column-to-column, and batch-to-batch relative standard deviations less than 7.2%, and low limits of detection of 0.5–0.9 ng/mL in real samples. Thiosildenafil was detected in four types of functional foods with the contents of 1.30–4.78 μg/g. This newly proposed in-tube SPME method based on poly(ATP-VBIMBr-EDMA) monolith may provide a simple, efficient, and promising alternative to daily monitoring of PDE-5 inhibitors in functional foods. [ABSTRACT FROM AUTHOR]