The effect of attapulgite (magnesium aluminium phyllosilicate) and its modified materials on the extractability of soil Cd and the accumulation of Cd in lettuce (Lactuca sativa) were investigated using a pot-culture experiment, and the immobilization mechanism of attapulgite and its modified materials was explored through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results showed that attapulgite and its modified materials could significantly reduce the Cd concentration in Lactuca sativa, with maximum reductions of 41.0% and 56.5%, respectively, and attapulgite modified materials treatments appeared more efficient than attapulgite treatments in reducing Cd uptake of Lactuca sativa. The saturated adsorption capacity for the adsorption of Cd2+ on attapulgite rose distinctly after being modified. Attapulgite and its modified materials could significantly reduce Cd content in soil CaCl2 extract at the dosage of 1%, with the maximum reduction rates of 34.2% and 34.3%, respectively. The attapulgite formed a complex to immobilize Cd mainly through the surface silanol and Cd2+ complexation reaction, while the modified attapulgite formed a complex mainly through the complexation of Cd2+ with carboxyl groups which existed in addition to the complexation with surface hydroxyl, thus reducing the mobility of Cd2+ and achieving remediation of Cd-contaminated soil. In summary, attapulgite and its modified materials can both be used for remediation of Cd-contaminated soil, and the mechanisms for this function were found to be different.

In this study we investigate the effects of cadmium stress on Astragalus membranaceus seedlings and the alleviative effects of attapulgite clay in growth substrate on cadmium stress to A. membranaceus seedlings. The results showed that the Y (Ⅱ) (effective photochemical quantum yield of PSⅡ photosynthetic), qP(photochemical quenching coefficient), ETR(the rate of non-cyclic electrontransport through PSⅡ), and chlorophyll content of the leaves were significantly decreased with the increase of cadmium concentrations, while the cadmium content, non-photochemical quenching(NPQ, qN) of the leaves and cadmium content, MDA content, plasma membrane permeability, and the damage degree of root apical membrane of the roots were significantly increased. Simultaneously, the activities of APX(ascorbate peroxidase), SOD(superoxide dismutase), POD(peroxidase), CAT(catalase), soluble protein content, and soluble sugar content of roots were increased first but then decreased with the increasing cadmium concentration. Under the condition of without Cd stress, the attapulgite clay into the growth substrate did not significantly affect above physiological indexes of leaves, but significantly increased SOD activity and soluble sugar content of roots and decreased the MDA content, damage degree of root apical membrane of roots, while other physiological indexes did not significantly change. Under cadmium stress, the presence of attapulgite clay in the growth substrate significantly alleviated the cadmium-induced decreases Y (Ⅱ), qP, ETR and chlorophyll content of leaves, and the CAT activity, soluble protein content, and soluble sugar content of roots. Under condition with cadmium stress, the presence of attapulgite clay significantly alleviated the cadmium-induced increases of leaves cadmium content, qN and NPQ, and the cadmium content, MDA content, plasma membrane permeability, damage degree of root apical membrane, SOD, POD, and APX activity of the roots. And, the alleviative effects of attapulgite clay on cadmium stress to A. membranaceus roots were more obvious with the increase of cadmium stress time. The above results showed that the addition of attapulgite clay into the growth substrate has certain alleviative effect on the cadmium stress to A. membranaceus seedlings.

In the present study, we synthesized an effective Pb(II) adsorbent from magnetic carboxyl-functionalized attapulgite (McAPT) and sodium alginate (Alg) by simple mechanical agitation at room temperature. The novel McAPT@Alg composite was systematically characterized using a number of instrumental techniques, and the effects of adsorbent dosage, initial concentration of Pb(II), adsorption time, pH, and temperature on the adsorption capacity were investigated by performing batch experiments. The obtained results demonstrated that adsorption equilibrium could be reached within 1.5 h, with the maximum adsorption capacity being 471.20 mg g-1 while the temperature was 297.2 K. The experimental data were suitable for application to the Langmuir isotherm model, and the adsorption kinetics agreed with the pseudo-second-order model. More importantly, a Pb(II) removal efficiency of >70% could be achieved after 6× adsorbent recycling, which demonstrated the excellent potential of McAPT@Alg for removing Pb(II) from contaminated water.

Most potato tubers were used as seeds and sprouted relatively slowly in soil, greatly influencing potato production. To solve this problem, an amphiphilic nanocomposite was fabricated by loading hydrophobic silica (H-SiO2) in hydrophilic attapulgite nest-like and used as a nano presprouting agent (NPA). This technology could conveniently adjust the occupation area ratio of water and air (OARWA) on the potato surface. NPA could endow potatoes with an appropriate OARWA and, thus, effectively accelerate sprouting. Additionally, NPA greatly decreased soil bulk density, facilitated earthworm growth, promoted potato growth, and increased the yield by 14.1%. Besides, NPA did not pass through the potato skin and mainly existed on the surface of potatoes. Importantly, NPA showed tiny influence on the viability of fish and nematodes, demonstrating good biosafety. Therefore, this work provides a promising presprouting approach for potatoes, which may have a potential application prospect in ensuring food supply.

A field study was carried out to investigate the sediment in-situ bioremediation by adding microbial activated beads. In this work, Calcium carbonate, silicon dioxide, activated carbon powder, attapulgite powder, sodium alginate, microbial liquid and polyvinyl alcohol were utilized to make the immobilized microbial activated beads. Field experiment results showed that the removal rate of NH4+-N, TN and COD in overlying water reached about 61.8%, 87.5% and 87.1%, respectively. The initial concentration of NH4+-N, TN and COD was 159 mg/L, 6.24 mg/L and 7.28 mg/L, whereas and the final concentration was 58 mg/L, 0.78 mg/L and 0.94 mg/L when water temperature, DO, pH and C/N ratio were 25-30 °C, 2-3 mg/L, 7.0-8.0 and 10-15, respectively. Moreover, under optimal temperature condition (25-30 °C), the removal rate of TOC, TN, heterotrophic bacteria and sulfur bacteria in the river sediment reached to 46.5%, 50.7%, 39.2% and 73.2%, respectively.

In current study, an attapulgite nanoparticles-based hybrid monolith was prepared by crosslinking 3-trimethoxysilylpropyl methacrylate modified attapulgite nanoparticles with acrylamide and N, N'-methylenebisacrylamide. The crosslinking of attapulgite into the hybrid monolithic matrix has notable increased the column efficiency of adenosine comparing with the neat one without attapulgite. The resulting hybrid monoliths showed good permeability and good mechanical stability. It was further applied for separation of polar compounds by hydrophilic interaction chromatography (HILIC). The key factors affecting the separation efficiency of the developed hybrid monoliths (i.e. acetonitrile content, salt concentration and pH in the mobile phase) have been completely investigated. The column efficiency was up to 147,613 plates/m for the HILIC separation of aspirin. Good repeatability of retention time was achieved, with relative standard deviations for run-to-run (n = 3), column-to-column (n = 3) and batch-to-batch (n = 3) in the range of 1.08-1.45%, 2.44-3.41% and 2.15-4.96%, respectively. We propose that the attapulgite nanoparticles-based hybrid monolith would provide a promising stationary phase for hydrophilic interaction chromatography.

A polyethyleneimine (PEI)-modified attapulgite was employed as a new adsorbent for solid-phase extraction (SPE) of chlorophenols (CPs) from environmental water samples. Key factors pivotal to extraction efficiency, such as organic additive, pH, salt, sample loading volume, elution volume, and sample loading flow rate, were investigated. The maximum adsorption capacity of CPs reached 38 mg/g, and the adsorption behavior could be described with the Langmuir isotherm model. The developed SPE procedure was then tested on river water samples. Of this cartridge, 0.4 g could be used to treat up to 100 mL of the water sample, with high recoveries achieved. The limit of detection (S/N = 3) and the limit of quantification (S/N = 10) were in range of 0.08-0.56 and 0.27-1.88 ng/mL, respectively. The mean recoveries of CPs spiked in river water samples ranged from 84.4 to 96.8% with relative standard deviations for the intra-day and inter-day less than 6.30%. The developed SPE method exhibited high sensitivity, high selectivity, excellent accuracy, and good repeatability to the analysis of trace CPs in complicated aqueous matrices. Graphical abstract Graphical abstract contains poor quality and small text inside the artwork. Please do not re-use the file that we have rejected or attempt to increase its resolution and re-save. It is originally poor, therefore, increasing the resolution will not solve the quality problem. We suggest that you provide us the original format. We prefer replacement figures containing vector/editable objects rather than embedded images. Preferred file formats are eps, ai, tiff and pdf.The separated figures were attached, which named Graphical abstract. ᅟ.

Petroleum refinery wastewater (PRW) treatments based on biofilm membrane bioreactor (BF-MBR) technology is an ideal approach and biofilm supporting material is a critical factor. In this study, BF-MBR with nano-attapulgite clay compounded hydrophilic urethane foams (AT/HUFs) as a biofilm support was used to treat PRW with a hydraulic retention time of 5 h. The removal rate of 500 mg/L chemical oxygen demand (COD), 15 mg/L NH4+ and 180 NTU of turbidity were 99.73%, 97.48% and 99.99%, which were 23%, 20%, and 6% higher than in the control bioreactor, respectively. These results were comparatively higher than that observed for the sequencing batch reactor (SBR). The death rate of the Spirodela polyrrhiza (L.) irrigated with BF-MBR-treated water was 4.44%, which was similar to that of the plants irrigated with tap water (3.33%) and SBR-treated water (5.56%), but significantly lower than that irrigated with raw water (84.44%). The counts demonstrated by qPCR for total bacteria, denitrifiers, nitrite oxidizing bacteria, ammonia oxidizing bacteria, and ammonia-oxidizing archaea were also higher in BF-MBR than those obtained by SBR. Moreover, the results of 16 s rRNA sequencing have demonstrated that the wastewater remediation microbes were enriched in AT/HUFs, e.g., Acidovorax can degrade polycyclic aromatic hydrocarbons, and Sulfuritalea is an efficient nitrite degrader. In summary, BF-MBR using AT/HUF as a biofilm support improves microbiome of the actived sludge and is reliable for oil-refinery wastewater treatment.

The interaction of CO with an attapulgite-supported Cu(ii)Cl2 catalyst has been examined in a micro-reactor arrangement. CO exposure to the dried, as-received catalyst at elevated temperatures leads to the formation of CO2 as the only identifiable product. However, phosgene production can be induced by using a catalyst pre-treatment where the supported Cu(ii)Cl2 sample is exposed to a diluted stream of chlorine. Subsequent CO exposure at ∼370 °C then leads to phosgene production. In order to investigate the origins of this atypical set of reaction characteristics, a series of X-ray absorption experiments were performed that were supplemented by DFT calculations. XANES measurements establish that at the elevated temperatures connected with phosgene formation, the catalyst is comprised of Cu+ and a small amount of Cu2+. Moreover, the data show that unique to the chlorine pre-treated sample, CO exposure at elevated temperature results in a short-lived oxidation of the copper. On the basis of calculated CO adsorption energies, DFT calculations indicate that a mixed Cu+/Cu2+ catalyst is required to support CO chemisorption.

In this study, a novel ionic liquid-type surfactant modified attapulgite named as 1-dodecyl-3-methylimidazolium bromide-attapulgite (C12MIM-ATP) is successfully prepared and applied in dispersive solid phase extraction (dSPE) for the fast determination of pyrethroid residues in tea drinks. The primary factors that influenced the extraction efficiency, including sorbent type, amount of sorbent, extraction time, desorption conditions, pH and ionic strength, are investigated. The optimized results reveal that the extraction and desorption equilibria are rapidly obtained within 1 min. Under the optimized conditions, good linearity (2-500 μg/L) is observed for four pyrethroids in tea drinks with determination coefficients (r2) ranged from 0.9992 to 1.0000. The limits of detection (LODs) are 0.6 μg/L for all pesticides. Acceptable extraction recoveries of target analytes are found from 90.28 to 107.56% with relative standard deviations (RSDs) less than 8.30% in real tea drink samples. The batch-to-bath repeatability is evaluated by recovery test on five independent synthesized C12MIM-ATP sorbents. Satisfactory batch-to-batch repeatability is obtained with the recovery factors varied in 15%. A small matrix effect is observed using C12MIM-ATP as the sorbent for detection pyrethroids in tea drinks.