Special-wetting materials have been broadly studied in various oil/water separation processes. However, there are granted numerous challenges in extremely durable materials with mechanical robustness, especially considering the great requirements in purifying emulsified oil/water mixtures. Herein, we present a facile route to prepare robust superhydrophobic surface by spraying Octadecyltrimethoxys modified attapulgite suspension combined with inorganic adhesive on mesh. The as-prepared meshes show eminent superhydrophobicity and acquire a gravity driven water-in-oil emulsion separation with efficiency above 99.7% and flux above 106.7 L m-2h-1 even after multiple cycles. In addition, the meshes exhibit robust and stable superhydrophobicity with water contact angles above 150° after 200 sandpaper abrasion (transverse shear force) and harsh sand impact (longitudinal impact force) cycles, and meanwhile, still maintain outstanding emulsion separation performance during tests. This study is meaningful for the development of fabricating low-energy separating materials with high efficiency and mechanical robustness for harsh chemical engineering.

Nickel being a toxic heavy metal is considered as a hazardous pollutant in the soil environment. The cultivation of edible vegetables on Ni contaminated soil can deteriorate plant quality which causes critical health issues to humans and animals. Therefore, the remediation for such Ni polluted soils has currently become a great challenge for the researchers. Contrastingly, lowering bioavailability of Ni in those soils based on applying appropriate immobilizing amendments demonstrating a target to relieve virulence to plants can remarkably diminish the environmental hazard. In this experiment, biochar (BR) along diverse clays like bentonite (BE), cationic-zeolite (C-ZE), chitosan (CN) and attapulgite (AP) as individual doses at 2% each in a soil synthetically spiked with Ni (at 50 ppm) magnificently immobilize Ni and curtailed its bioavailability to lettuce (Lactuca sativa L.). In addition, the related influences of planned treatments on translocation of Ni to shoots and leaves, antioxidant preventive system over oxidative injury, biochemistry and nutritional ability of lettuce were monitored. Results suggested that the CN2% treatment performed excellently in terms of reducing Ni concentrations in leaves and roots of lettuce plants along bioavailable Ni in the soil after plant harvest. Surprisingly, the BR2% treatment efficiently promoted enzymatic activities in the soil and developed moisture content, photosynthesis, biomass, biochemistry, and nutrition (both micronutrients and macronutrients) and antioxidant preventive system while diminished Ni oxidative injury in lettuce plants over rest of the treatments. Finally, our results confirmed that individually applying CN at 2% in a Ni contaminated soil could significantly control Ni bioavailability, whereas, application of BR at 2% could remarkably develop aforementioned parameters in lettuce plants.

Lipopeptides possess excellent broad spectrum antimicrobial activity. Different lipopeptides have their own unique chemical structures, properties and biological activities. Quantitative analysis of the lipopeptides iturin and surfactin and their homologues produced by Bacillus natto NT-6 subjected to different culture media, shaking speed of rotary shaker, and liquid and solid fermentation methods was conducted using LC-MS. For iturins, liquid-state fermentation in Landy medium at a shaking speed of 160 r min-1 was the most suitable for maximal homologue production. Addition of 0.4% attapulgite powder increased production by 1.92-fold; activated carbon significantly reduced production. For surfactin homologues, solid-state fermentation in potato dextrose broth medium at shaking speed > 160 r min-1 was the best. Addition of 0.4% attapulgite powder increased production by 1.96-fold; activated carbon had no effect. Thus it is clear that fermentation conditions can be manipulated to maximize iturin and surfactin production.

Biochar has been frequently applied for the treatment of heavy metals pollution in water and soil, its effect in contaminated sediments needs further research. In order to improve the ability of biochar for heavy metals immobilization in sediment, this study prepared functionalized biochar/attapulgite composite by pyrolysis of the clay attapulgite and zinc chloride pretreated rice straw biomass. Compared with the original biochar, biochar/attapulgite composite had a large increase in specific surface area, pore volume, oxygen-containing functional groups and cation exchange capacity. Biochar could effectively improve the dispersibility of attapulgite as a matrix. The results showed that the biochar/attapulgite composite could effectively reduce the bioavailable fraction of As and Cd in the river sediment, which had a great improvement compared with the raw biochar. After the sediment was treated by different biochar/attapulgite composites, the concentrations of As and Cd in the overlying water and pore water, and the content of acid extractable and TCLP extractable As and Cd in solid phase of sediment decreased significantly. Both zinc chloride activation and attapulgite were benefit for As and Cd immobilization in sediment by biochar/attapulgite composite. The results suggested that biochar/attapulgite composite can be used as an efficient in-situ sorbent amendments to improve the immobilization ability of the sediment to heavy metals. This article is protected by copyright. All rights reserved.

The performance of Fe3O4/attapulgite (APT) nanoparticles in Pb(II) adsorption from aqueous solutions could be improved by modifying the particles with aminopropyltriethoxysilane (APTS) and then combining with chitosan (CS) into beads. After preparing the APTS-Fe3O4/APT@CS beads, their surface morphology and crystal phases were analyzed by Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. The magnetic properties of APTS-Fe3O4/APT@CS were studied by a vibrating sample magnetometer, while their heat resistance and stability were characterized by thermal weight analysis. A recycling test and comparison of adsorption capacities were also carried out. The adsorption capacity of Fe3O4/APT was improved by the modification with APTS and CS. The adsorption process conforms to the pseudo-second-order kinetic and Langmuir adsorption isotherm models. The adsorption of Pb(II) reaches a maximum of 625.34 mg/g, which compares favorably with other reported adsorbents. The results show that APTS-Fe3O4/APT@CS is a promising hybrid adsorbent for effective removal of Pb(II) from water.

Cd contamination in agricultural soils threatens the safety of agricultural products and poses human health risk via food chain. However, the remediation of Cd polluted alkaline soils has not drawn the public concern, and the corresponding efficient amendments that can reduce Cd accumulation in crop grains are relatively few. In current study, mercapto-modified attapulgite (MA in abbreviation) was selected as the amendment to conduct winter wheat (Triticum aestivum L.) cultivation pot experiment to investigate the effect of MA on Cd accumulation in winter wheat and Cd bioavailability in alkaline soil. MA had no adverse impact on the normal growth of winter wheat but could inhibit Cd accumulation in wheat grain of both cultivars grown in alkaline soil with a maximum reduction of 75%, while pH-regulating amendment sepiolite had no reduction effect. In the term of soil chemistry, MA could decrease the zeta potential of soil particles and enhance the sorption amount of Cd on soil particles, resulted in the increase of Fe-Mn-oxides bounded Cd fraction in alkaline soil. The enhanced sorption effect combined with complexation effect of MA itself, made the exchangeable and bioavailable Cd concentrations in the soil decrease. In the term of plant uptake, MA could inhibit the uptake of Cd via roots from the soil, and hinder Cd transfer from roots to grains. MA had environmental friendliness and capability in the aspect of soil pH, effective cation exchange capacity and available micronutrients in the soil. The high performance of MA in inhabitation of Cd in winter wheat revealed that it was an efficient immobilization agent with great application potential for Cd-polluted alkaline soil.

In this study, through in-situ polymerization process, a novel composite of attapulgite/hydrophilic molecularly imprinted monolithic resin (AT/HMIMR) were prepared in pipette tips for extraction trace plant growth regulators in cucumbers. In the preparation procedure, fibrillar attapulgite nanoparticles were embedded to increase extraction capacity, polyethyleneglycol-6000 was employed as a dual-function porogen, that acted as both the structure-directing agent of the HMIMR and the attapulgite dispersant. N-(1-naphthyl) ethylenediamine dihydrochloride was used as a dummy template to accurate quantification on extraction procedures. Experimental parameters of AT/HMIMR for extracting plant growth regulators from cucumbers were optimized, and the results showed that the recoveries of ranged from 92.4% to 101.1% with relative standard deviations ≤ 6.5% (n = 3). Considering its microporous monolithic column structure, multiple adsorption mechanism, and specific selectivity, AT/HMIMR shows promise for applications that require specific recognition for the analytes in real complex samples.

The use of attapulgite (ATP)-based materials for adsorption of pollutants from water and wastewater has received growing attention. However, recovering ATP-based adsorbents remains a challenge. In this study, a magnetic adsorbent ATP/CoFe2O4 with high tannic acid (TA) adsorptive capacity was fabricated via a facile co-precipitation approach and was well characterized. The loaded CoFe2O4 particles were embedded into the adsorbent surfaces to allow magnetic separability. For this material, its TA adsorption kinetics, isotherm behavior, and magnetic separation efficiency are reported. The developed magnetic composites had rapid sorption kinetics of 3 h, high sorption capacity of 109.36 mg/g, and good magnetic separation efficiency of 80%. The used ATP/CoFe2O4 was successfully regenerated by NaOH and reused five times without a substantial reduction in TA removal and magnetic performance. Intermolecular hydrogen bonding formation and surface complexation were identified as the sorption mechanisms of TA by ATP/CoFe2O4.

Nowadays, the problem of heavy metal pollution in vegetables is received wide attention. In this work, attapulgite clay (ATTP), as a cheap and readily available inorganic mineral material, was modified with nano zero-valent iron (nFe0@ATTP) for heavy metal immobilization in soil. Batch experiments were employed to evaluate the optimal remediation performance by ATTP before and after modified with nFe0 through planting Pakchoi (Brassica chinesis L.) in Cd, Cr, and Pb contaminated soil from Changsha. The results showed that amendments can all increase the pH value of soils, and notably decrease the concentration of extractable Cd, Cr, and Pb in soil. The germination rate and root length of Pakchoi were promoted, and the activities of peroxidase (POD), catalase (CAT), and malondialdehyde (MDA) contents were notably reduced besides superoxide dismutase (SOD) activity after treatments with ATTP and nFe0@ATTP. Vicia faba-micronucleus test indicated that the application of amendments reduced the toxicity of heavy metals on the genetic material of Vicia faba root tip cells. The nFe0@ATTP were found to well convert Cd, Cr, and Pb into less bioavailable state in soil, thus blocking heavy metal uptake by plants. This material could be a promising amendment for heavy metals contaminated soil.