Palygorskite Research Articles

Attapulgite and multiwalled carbon nanotubes co-integrated hierarchical porous polyacrylonitrile membrane as a multifunctional interlayer for lithium-sulfur batteries with enhanced performance

• ATTP and MWCNTs co-integrated porous PAN membrane was first fabricated. • The membrane was investigated as a multifunctional interlayer for Li-S batteries. • A synergistic effect of ATTP and MWCNTs effectively suppress the shuttle effect. • The cell with such interlayer demonstrates superior cycling stability . As a kind of natural porous nanorods, attapulgites (ATTP) are widely used in many fields because of their high specific surface area, high porosity and strong adsorption ability. In this work, ATTP and multiwalled carbon nanotubes (MWCNTs) co-integrated polyacrylonitrile (PAN) hierarchical porous membrane (ATTP/CNTs@PAN) has been fabricated and investigated as a multifunctional interlayer for lithium-sulfur batteries. Due to a synergistic effect of ATTP and the carboxylated MWCNTs, the porous interlayer is able to effectively suppress the shuttle effect by trapping and confining the dissolved polysulfides. Meanwhile, the addition of MWCNTs improves the conductivity of the composite membrane, which is beneficial for the reutilization of the active species. Therefore, the cells with the interlayer demonstrates superior electrochemical performance, delivering a high initial discharge capacity of 1283 mAh g −1 at 0.2 C, and retaining 785 mAh g −1 after 300 cycles with a Coulombic efficiency exceeding 99%. Meaningfully, this porous composite membrane is low-cost and very effective for high performance Li-S batteries.

Nanostructured chitosan-palygorskite hybrid microspheres for controlled delivery of thymol

Hybrid microspheres from palygorskite (PAL) nanoclay and crosslinked chitosan (QS) were prepared with the emulsion method to trap and control the release of thymol (TIM). The morphology of the microspheres was characterized by scanning electron microscopy and x-ray diffraction. The size of the microspheres, the swelling rate, the encapsulation efficiency and thymol release rate were characterized. Compared to pristine chitosan microspheres, hybrid microspheres showed the highest encapsulation efficiency. The average particle sizes of the QS and QS-PAL microspheres are in a range of 20 to 50 μm, with a size distribution of the hybrid microspheres showing less size polydispersity. The QS-PAL microspheres have a higher swelling rate than the QS microspheres. The lowest swelling degree, 88%, was from the microspheres without PAL cross-linked with 950 μl of glutaraldehyde (GL), and the highest swelling degree, 146%, was from the microspheres with 10% PAL crosslinked with 630 μl of GL. The thymol release kinetics was modified by the palygorskite content of the chitosan hybrid microspheres.

One-step dip-coating method for preparation of ceramic nanofiber membrane with high permeability and low cost

Ceramic nanofiber membrane (CNM) based on attapulgite (APT) without any intermediate layer neither any cracks was fabricated by a one-step dip-coating method. The effects of sintering temperature and dip-coating time on the physicochemical properties and performances of prepared CNMs were investigated. The increase of the sintering temperature up to 700 °C reduced the bending strength, porosity and chemical stability of APT-based CNMs. Meanwhile, with the dip-coating time increased, the membrane thickness increased thereafter reduced. The APT-based CNM fabricated at a sintering temperature of 600 °C and with a dip-coating time of 15 s had an average pore size of 20.4 nm, high porosity (above 60 %), good permeability of 118 L/m2 h bar and a rejection of 96.6 % polymers with a molecule weight of 600 kDa. All these properties clearly suggest the practicability of the one-step dip-coating method to prepare ceramic nanofiber membranes.

Effect of pectin and attapulgite filler on swelling, network parameters and controlled release of diltiazem hydrochloride from polyacrylic copolymer gel

Pectin grafted polyacrylic copolymer hydrogels were made by free radical crosslink copolymerization of acrylic acid (AA) and acrylamide (AM) in an aqueous solution of pectin. N′N-methylene bis acrylamide (MBA) was used as a crosslinker. During the polymerization reaction the attapulgite (APG) filler was also incorporated in situ into the network of the copolymer gel. Several filled hydrogels were prepared by varying the amount of pectin and APG filler. These hydrogels were characterized by FTIR, 13C NMR, XRD, TGA, SEM, mechanical properties, DMA, swelling, diffusion characteristics and network parameters. The release kinetics of a model drug diltiazem hydrochloride (DT) was studied with these hydrogels. The wt% of pectin, APG and MBA was optimized with a central composite design (CCD) model of response surface methodology (RSM) with equilibrium swelling ratio (ESR), drug adsorption (mg/100 mg gel) and drug release% in 16 h as response. Accordingly, the hydrogel prepared with 5:1 AA:AM molar ratio, 25 wt% monomer concentration, 1% each of initiator and MBA concentration, 18 wt% pectin and 2 wt% APG showed an optimized ESR of 17.75, drug loading of 27.58 and a drug release % of 92.5 in 16 h at a solution pH of 7.4.

Nanomaterials Modified Drilling Fluid for Improving Deep Drilling Conditions

Abstract Achieving stability of drilling fluids (DFs) rheology with high temperature and high pressure (HTHP) has always seen a growing focus with increasing pursuits of deep drilling operations to maximize hydrocarbon recovery. Since there is no boundary of how deep the drilling technology can be pushed to access deep-lying reservoirs, the quest to improve and stabilize the drilling fluids rheology is an open-ended and ongoing matter. This paper presents an investigation of two distinct clays namely sepiolite (SP) and attapulgite (AT) in nanoform as water-based drilling fluid (WBDF) additives for improved and stable rheological properties. The process of material sourcing, characterization, development in nanoform, and testing as a drilling fluid additive at low and high temperature and pressure conditions are the main focus of this study. Through experiments, it was determined that 30–60 nm size range and 4 wt% concentration of developed nanomaterials yielded the optimal performance. Various tests were then performed at HTHP, and the stability of nanosepiolite (NSP) and nanoattapulgite (NAT) in 4 wt% concentration was compared with regular drilling fluid additive (bdf403) which is used as a common rheology stabilizer in the industry. It was found that for NSP and NAT-modified drilling fluids, the yield point, plastic viscosity, and gel strength were found to be retained at temperatures and pressures of up to 180 °C and 15 ksi, respectively, in contrast to bdf403 WBDF which deteriorated at much lower temperature and pressure. NSP additives were found to be more effective than NAT additives. The results confirmed a strong dependence of the DF stability on the morphological characteristics of the tested clays, implying that the properties of the DFs can be tailored by modifying the clay morphologies, particularly in the nanoform.

Multifunctional palygorskite@ZnO nanorods enhance simultaneously mechanical strength and antibacterial properties of chitosan-based film

A general and effective strategy was developed for improving simultaneously the mechanical strength and antibacterial performance of biopolymer-based films. The well-dispersed zinc oxide (ZnO) nanoparticles were in-situ loaded on non-toxic natural palygorskite (PAL) nanorod to form an antibacterial PAL@ZnO composite nanorod, which can be embedded into chitosan/gelatin (CS/GL) film to produce the composite films with noticeably enhanced mechanical properties and antibacterial activity against S. aureus and E. coli bacteria (inhibition zones are 21.82 ± 0.95 mm and 16.36 ± 1.64 mm, respectively). The toughness of films enhances to 35.13 ± 0.95 MPa and the moisture uptake decreases to 23.74 ± 0.02% after embedding 3% and 9% of PAL@ZnO, respectively. In addition, incorporating PAL@ZnO nanorods also significantly enhanced the water resistance, and thermal stability of film. This work provides an alternative way for the development of antibacterial films with potential applications in many fields such as food packing.

Superior elimination of Cr(VI) using polydopamine functionalized attapulgite supported nZVI composite: Behavior and mechanism

In this study, a polydopamine (PDA) modified attapulgite (ATP) supported nano sized zero-valent iron (nZVI) composite (PDA/ATP-nZVI) was rapidly synthesized under acidic conditions, and employed to alleviate Cr(VI) toxicity from an aqueous solution. Kinetic studies revealed that Cr(VI) adsorption process followed the pseudo-second order model, suggesting chemisorption was the dominant adsorption mechanism. Liu isotherm adsorption model was able to better describe the Cr(VI) adsorption isotherm with the maximum adsorption capacity of 134.05 mg/g. The thermodynamic study demonstrated that the adsorption process occurred spontaneously, accompanied by the increase in entropy and endothermic reaction. Low concentrations of coexisting ions had negligible effects on the removal of Cr(VI), while high concentrations of interfering ions were able to facilitate the removal of Cr(VI). Reactive species test revealed that Fe2+ played a key role in Cr(VI) reduction by PDA/ATP-nZVI. PDA enhanced the elimination of Cr(VI) via donation of electrons to Cr(VI) and acceleration of Fe3+ transformation to Fe2+. Furthermore, PDA was able to effectively inhibit the leaching of iron species and generation of ferric hydroxide sludge. Mechanistic study revealed that 72% of Cr(VI) elimination was attributed to reduction/precipitation, while 28% of Cr(VI) elimination was due to the surface adsorption.

Fabrication of attapulgite/magnetic aminated chitosan composite as efficient and reusable adsorbent for Cr (VI) ions.

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.

Polyvinylidene Fluoride/Nanoclays (Cloisite 30B and Palygorskite) Mixed Matrix Membranes with Improved Performance and Antifouling Properties

In this study, it was attempted to prove the effectiveness of nanoclays as economical and nontoxic nanofillers through comparison with carbon nanotubes (CNTs). Two hydrophilic nanoclays, namely, Cloisite 30B and palygorskite (PGS), were used as nanofillers to improve the morphology and performance of polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes. A nonsolvent-induced phase separation (NIPS) method was used to prepare mixed matrix membranes (MMMs). The effects of the nanoclays on morphology, performance, and antifouling properties of the prepared MMMs were investigated. It was found that compared to PVDF membranes, the hydrophilicity, antifouling properties, and morphology of the fabricated MMMs are improved significantly. Compared to PVDF membranes, pure water flux (PWF) values of the MMMs containing the optimum contents of Cloisite 30B (0.5 wt %) and palygorskite (1 wt %) improved by 44.7 and 61.7%, respectively. Acid-treated CNTs were used as a reference additive, and the performance and antifouling properties of the prepared PVDF/nanoclay MMMs were compared with the prepared PVDF/acid-treated CNT MMMs. It was found that the PWF values of the MMM containing optimum contents of PGS and Cloisite 30B nanoclays are 86 and 77%, respectively, compared with that of the MMM containing acid-treated CNTs. The PVDF/Cloisite 30B MMM exhibited lower PWF than the PVDF/PGS MMM, which could be attributed to the plate-like structure of Cloisite 30B. Also, the flux recovery ratio (FRR) values of the mixed matrix membranes containing optimum contents of PGS and Cloisite 30B nanoclays were 95.65 and 92.06%, respectively, compared to that of the MMM containing acid-treated CNTs. Also, the BSA rejections of the prepared MMMs containing optimum contents of Cloisite 30B and palygorskite were comparable with that of the MMM containing acid-treated CNTs. Therefore, nanoclays can be suggested as economical and ecofriendly nanofillers for improving the PVDF membrane performance.

Structure, Morphology Features and Photocatalytic Properties of α-Ag2WO4 Nanocrystals-modified Palygorskite Clay

Aims: In the present study, we investigate the photocatalytic properties of α-Ag2WO4 nanocrystals- modified Palygorskite (PAL) clay synthesized by the impregnation method. The PAL clay was chemically purified and heat-treated (500 ºC for 2 h), which served as an excellent supporting matrix for loading α-Ag2WO4 (α-AWO) nanocrystals. Background: Water contamination is one of the most serious problems affecting human health, ecosystem survival, and the economic growth of societies. Industrial effluents, such as textile dyes, when not treated and improperly discharged into water resources are considered the main cause of water pollution. Thus the scientific community has been developing effective remediation technologies based on advanced oxidative processes to reduce the harmful effects of these organic pollutants. Objective: This study aimed to improve the photocatalytic activity of PAL clay with α-AWO nanocrystals to degradation of Rhodamine B (RhB) dye. Methods: We purify and heat-treated the PAL clay, synthesize nanocrystals ofα-AWO nanocrystals and modify PAL clay with 30% α-AWO nanocrystals by the impregnation method. The modified PAL clay was able to improve RhB dye degradation. The materials were characterized by XRD, RAMAN,FE-SEM, FT-IR, XRF, etc. The samples were used as photocatalysts under UV-C lamps for the degradation of RhB dye in order to analyze its catalytic performances. Results: The PAL clay modified with 30% α-AWO nanocrystals showed a catalytic efficiency of 79%, and degradation kinetics about 16 times higher when compared to PAL-500 only purified and heat-treated at 500 ºC. In this way, this PAL-modified is an alternative as a low-cost photocatalyst for the degradation of RhB dye. Conclusion: Ultraviolet-visible spectra revealed that our materials have optical band gap energies controlled by indirect and direct electronic transitions and suitable to be activated under ultraviolet illumination. The adequate amount (30 wt.%) of α-Ag2WO4 nanocrystals added to PAL brought significant improvement in the photocatalytic activity for the degradation of rhodamine B. Finally, a photocatalytic mechanism was proposed in detail.

Preparation, Characterization, Application and Structure Evolution of Attapulgite: From Nanorods to Nanosheets

Attapulgite (AT) nanorods are generally regarded as one-dimensional materials and have been widely used in many fields. Two-dimensional (2D) AT nanomaterials have remained quite rare due to the difficulty of assembling from one-dimensional nanorods. Herein, we have prepared a novel type of single-layered 2D palmate AT nanosheets (AT-NS) with uniform size by a solvothermal synthesis process. The morphology and structure of the obtained 2D nanosheets were characterized by SEM, TEM, AFM, XRD, FTIR, and XPS. It was found that the AT nanosheets have a mean thickness in the range of 30–50 nm, and the length and width are in the range of 30 nm-2 μm. The structure evolution from AT nanorods to nanosheets were systematically studied and revealed. It was shown that the amination of AT and the introduction of trivalent iron ions (Fe3+) ions into the AT materials play key roles in the formation of AT-NS. The AT nanorods are connected each other by the AT-NH2 groups coupling with the Fe3+ ions on the AT surface. More importantly, the Fe3+ substitute the Al3+, Mg2+ in AT mainly along the (110) planes. Therefore, the coordination of trivalent iron ions with amino groups occurs on the AT (110) plane. As a result, multiple nanorods are connected side by side to form the 2D nanosheets in a palmate shape. It is believed that the special morphology and structure of the 2D AT-NS material may bring some outstanding performance, which makes it have potential important application such as the demulsification of crude oil-in-water emulsion. In addition, the confined 2D assembling methodology offers us a new way to design and prepare novel materials with 2D structure.

Rapid capturing of oil-degrading bacteria by engineered attapulgite and their synergistic remediation for oil spill

HypothesisHigh-efficiency dispersion and enhanced biodegradation play important roles in the treatment of oily wastewater. Due to the flaws of chemical surfactants, it is necessary to study the alternative dispersants that are eco-friendly and sustainable. Therefore, applying natural attapulgite (ATP) to coat Brevibacillus parabrevis for dispersion and biodegradation was studied. ExperimentsTo capture negatively charged bacteria in water, ATP was modified by positively charged Poly (allylamine hydrochloride) (PAH). The capturing capability of Poly (allylamine hydrochloride)-attapulgite (PAH-ATP) particles for bacterial cells, emulsification of PAH-ATP particles and bacteria on oil, toxicity of PAH-ATP to bacteria, biodegradation of oil, etc., were comprehensively investigated. FindingsPAH-ATP modified bacteria show a highly effective emulsification for oil due to the synergism of PAH-ATP and bacteria. The emulsion stabilized by (PAH-ATP)@bacteria presents small and stable oil droplets in one month, which is benefit for the following biodegradation. Compared with bare bacteria and PAH-ATP, PAH-ATP can capture bacteria to the surface of the oil droplets which can greatly improve the degradation of oil pollution. Importantly, the presence of PAH-ATP does not inhibit the reproduction and activity of bacteria. Treatment of oily wastewater by combining natural nanoparticles and oil-degrading bacteria has the advantages of economy, environmental protection, and sustainability.

TiO2/CTS/ATP adsorbent modification and its application in adsorption-ultrafiltration process for dye wastewater purification.

Industrial dyeing produces highly polluting wastewater and threatens the environment. Effective treatment of dyeing wastewater is a crucial step to prevent toxic chemicals from entering receiving waters. This study aimed to assess a modified attapulgite (ATP)-based adsorbent for dyeing wastewater purification by introducing chitosan (CTS) and titanium dioxide (TiO2) into the adsorbent material named TiO2/CTS/ATP. It was found that after modification, the adsorbent showed a lower hydrophilicity, as demonstrated by an increase in the water contact angle from 9.1° to 42°, which could reduce the water adsorption tendency and potentially facilitate contaminants adherence. The modification also led to a significantly increased specific surface area of 79.111 m2/g from 3.791 m2/g and exhibited more uniform and smaller particle size (reduced from 3.99 to 2.52 μm). When the TiO2/CTS/ATP adsorbent was applied to the adsorption of Congo red solution, the adsorption efficiency was observed to reach to 97.6% at the dosage of 0.5 g/L. Furthermore, the combination of adsorption and ultrafiltration was able to achieve 99% Congo red removal. Adsorption pretreatment prior to the ultrafiltration also enabled to reduce membrane fouling, increased the reversible membrane fouling, and resulted in a considerably lower transmembrane pressure as compared with the direct ultrafiltration filtration system.

A research on the removal characteristics of naphthol Green B from wastewater using nanomaterials nZVI/CS/APT

ABSTRACT Nanoscale zero-valent iron (nZVI) is one of the most effective materials for environmental restoration. However, nZVI particles is liable to aggregate and passivate rapidly, which leads to a decline its effectiveness in contaminant treatment. In this study, an efficient nanomaterial has been developed for decolourisation and degradation of a metal complex dye Naphthol Green B (NGB). To protect nZVI and enhance the removal efficiency that was modified with chitosan (CS) and attapulgite (APT). The removal of NGB as a function of pH, reaction time, adsorbent dosage and initial concentration were studied. The nZVI/CS/APT had best removal efficiency of NGB due to the excellent synergistic combination of CS/APT adsorption and nZVI reduction. And the nZVI/CS/APT possessed fast adsorption kinetics and the maximum adsorption capacity for NGB could reach 192.30 mg/g. The outstanding performance of nZVI/CS/APT provide promising material for detoxification contaminant from wastewater.

A one‐pot biosynthesis of an aerogel composite based on attapulgite clay/bacterial cellulose to remove Pb 2+ ion

A one‐pot biosynthesis of an aerogel composite based on attapulgite clay/bacterial cellulose to remove Pb ²⁺ ion

Synthesis, characterization, and adsorption properties of collagen and attapulgite‐filled copolymer biocomposites: Batch and column studies

AbstractSeveral biocomposites were synthesized by copolymerizing hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) at varied molar ratios in the presence of different wt% of collagen (CLG) and attapulgite (APG) clay. The structure and properties of the biocomposite adsorbents were characterized by Fourier transform infrared apectroscopy, nuclear magnetic resonance, X‐ray photo electron spectroscopy, X‐ray diffraction, scanning electron microscope, transfer electron microscopy, energy‐dispersive X‐ray analysis, differential thermal analysis–thermogravimetric analysis, point zero charge analysis, mechanical properties, and pH reversibility tests. The synthesis variables were optimized with a central composite design of response surface methodology (RSM). The biocomposite prepared with an optimized composition of 1.5 wt% CLG, 1.7 wt% APG, and 5:1 molar ratio of HEMA:IA showed an adsorption capacity (Qe, mg/g) of 674.4/602.4 for methylene blue (MB)/Rose Bengal (RB) dye from a feed containing 200 mg/L of MB + RB dye mixture in batch mode. In a fixed bed in column mode, the optimized biocomposite showed a removal% of 82.8/71.3 for 100 mg/L inlet concentration, 20 ml/min flow rate, and 20 mm bed height with a breakthrough time of 23/31 min and a mass transfer coefficient (kmtc × 105 cm/s) of 8.36/7.67 for MB/RB as single dye solution.

Attapulgite-MXene Hybrids with Ti3C2Tx Lamellae Surface Modified by Attapulgite as a Mechanical Reinforcement for Epoxy Composites.

As a member of two-dimensional (2D) materials, MXene is an ideal reinforcement phase for modified polymers due to its large number of polar functional groups on the surface. However, it is still relatively difficult to modify any functional groups on the surface of MXene at present, which limits its application in enhancing some polymers. Herein, one-dimensional (1D) attapulgite (ATP) nanomaterials were introduced onto the surface of MXene to form ATP–MXene hybrids, which successfully improved the mechanical properties of the epoxy composites. ATP with appropriate content can increase the surface roughness of the MXene lamellae to obtain better interface interaction. Therefore, remarkable enhancement on the mechanical property was achieved by adding M02A025 (0.2 wt % MXene and 0.25 wt % ATP), which is the optimum composition in the hybrids for composite mechanical properties. Compared to neat epoxy, the tensile strength, flexural strength and critical stress intensity factor (KIC) of M02A025/epoxy are increased by 88%, 57%, and 195%, respectively, showing a high application prospect.

Effectiveness evaluation of environmentally friendly stabilizers on remediation of Cd and Pb in agricultural soils by multi-scale experiments

Utilizing heavy-metal-contaminated agricultural land safely is an urgent problem. Comprehensive evaluation of remediation efforts and economic benefits of stabilizers on contaminated soil are the most important means to address this problem. Environmentally friendly stabilizers attapulgite (APT), attapulgite/carbon (APT/C), and phosphate mineralization bacteria products (PMBP) were analysed for their ability to stabilize Cd and Pb in soil under incubation conditions and to decrease the uptake of heavy metals by vegetables under greenhouse and field conditions. In incubation, pot, and field experiments, APT/C best stabilized Cd in soil, while PMBP had the best stabilization effect on Pb in soil. Based on effectiveness, cost, and improved yields, the optimal amounts of stabilizers were 5‰ APT/C and 0.21‰ PMBP. In practical applications, PMBP should be appropriately supplemented annually to ensure its efficiency. APT/C and PMBP can be used to treat heavy-metal-contaminated agricultural soils not only in this study area, but also in other similar heavy-metal-contaminated agricultural lands. This study provides a new perspective for evaluating the performance of eco-friendly heavy metal stabilizers in soils by analysing their efficiency, economic benefit, and application time through multiple rounds of multi-scale experiments.

Polyaniline modified attapulgite incorporated in alkyd paint for carbon steel corrosion inhibition

ABSTRACT In the present work, polyaniline (PANI) modified attapulgite (ATP) nanocomposite was synthesized and employed as reinforcements to enhance the corrosion resistance of the alkyd coating. The morphological and structural properties of the synthesized ATP/PANI were characterized by transmission scanning electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Electrochemical impedance spectroscopy (EIS) was employed to investigate the corrosion protection performance of the alkyd coatings, showing the improved corrosion resistance in the presence of the ATP/PANI nanocomposite. Scanning Kelvin probe (SKP) and Raman spectroscopy were performed to characterize the metal passivation inhibition ability of composite coatings. Compared with blank coating, the SKP results revealed a clear decrease in electrochemical activity at the scratch of ATP/PANI coating. Results from Raman spectrum indicated that the protective capability of the scratched coating can be recovered through the passivation of polyaniline to form stable oxide film (Fe2O3) on metal surface.

Aligned Attapulgite-based aerogels with excellent mechanical property for the highly efficient solar steam generation

Solar steam generation has attracted much attention due to its efficient and ecofriendly characteristics for application in water desalination and wastewater treatment. Many strategies have been developed to prepare the photothermal conversion materials. However, it is a challenge for preparing the materials with high energy efficiency, long durability and excellent salt resistance under 1 kW·m−2 illumination by using low-cost materials and simple method. Here, we report an ATP (Attapulgite) based PArG aerogel with low thermal conductivity (0.167 W·m−1·K−1), high mechanical property and superhydrophilicity by using combination of physical/chemical crosslinking of the ATP, PVA, GO and PA and freeze-drying for the efficient solar steam generation. The as-prepared PArG-A30 aerogel shows aligned three-dimensional porous structure and possesses high evaporation performance both in salt solution and the simulated seawater. The evaporation rate is calculated to be 1.4914 kg·m−2·h−1 for pure water, 1.4382 kg·m−2·h−1 for 20% of NaCl solution and the corresponding energy conversion is found to be 89.5% and 86% under 1 kW·m−2 illumination. In addition, the as-prepared PArG-A30 aerogel shows excellent durability and salt resistance in 20% NaCl solution, indicating the excellent the desalination performance of the resultant PArG-A30 aerogels. This study may offer a new approach to scalable fabricate a novel solar steam generator for the efficient solar steam generation by using simple method and low-cost materials.