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The over-reliance on tetracycline antibiotics (TC) in the animal husbandry and medical field has seriously affected the safety of the ecological environment. Therefore, how to effectively treat tetracycline wastewater has always been a long-term global challenge. Here, we developed a novel polyethyleneimine (PEI)/Zn-La layered double hydroxides (LDH)/cellulose acetate (CA) beads with cellular interconnected channels to strengthen the TC removal. The results of the exploration on its adsorption properties illustrated that the adsorption process exhibited a favorable correlation with the Langmuir model and the pseudo-second-order kinetic model, namely monolayer chemisorption. Among the many candidates, the maximum adsorption capacity of TC by 10 %PEI-0.8LDH/CA beads was 316.76 mg/g. Apart from that, the effects of pH, interfering species, actual water matrix and recycling on the adsorption of TC by PEI-LDH/CA beads were also analyzed to verify their superior removal capability. The potential for industrial-scale applications was expanded through fixed-bed column experiments. The proven adsorption mechanisms mainly included electrostatic interaction, complexation, hydrogen bonding, n-π EDA effect and cation-π interaction. The self-floating high-performance PEI-LDH/CA beads exploited in this work provided fundamental support for the practical application of antibiotic-based wastewater treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Elastic brushite/polyethyleneimine/nanofibrillated cellulose aerogel was developed. • The coupling of brushite and polyethyleneimine enhanced adsorption property. • PNFCA/BRU-0.2 exhibited high selectivity for Cu(II) with 332.66 mg/g. • The continuous flow purification of copper-containing wastewater was realized. • PNFCA/BRU-0.2 could block the toxicity of heavy metals to crops. To achieve efficient removal of copper(II) from heavy metal wastewater, designing an eco-friendly and low-cost adsorbent is highly desirable. Here, a novel air- and underwater shape-memory cellulose aerogel was reported via coupling brushite and polyethyleneimine (PEI)-modified nanofibrillated cellulose (NFC) for selectively adsorbing Cu(II) ions. The adsorption kinetic and isotherm studies were consistent with pseudo-second-order model and Langmuir model, indicating the removal of Cu(II) was a monolayer chemisorption process. Benefiting from the open three-dimensional (3D) framework structure and abundant exposed active sites, such compressible aerogel exhibited excellent adsorption capacity of 332.66 mg/g for Cu(II). In addition, the developed aerogel could be conveniently used as a continuous flow filter for successive purification of industrial wastewater, where the up-to-standard treatment volume was about 5.6 L. The Cu(II)-loaded aerogel could be regenerated after being eluted by 0.1 M EDTA-2Na, and its structure, shapeability and selective adsorption properties were hardly affected even after 8 consecutive cycles. Mechanistic analysis confirmed that the surface complexation, ion exchange and chemical deposition were the main driving forces for the superior adsorption performance. Finally, PNFCA/BRU could inhibit the contamination of crops by heavy metals, which was a great safeguard for wheat growth. [ABSTRACT FROM AUTHOR]

[Display omitted] • The highly entangled hydrogel adsorbent combines both elasticity and toughness. • The prepared hydrogel has low hysteresis and high fatigue resistance. • The hydrogel adsorbent achieves controllable swelling-deswelling. • The adsorption capacity and rate increase by >10 times. • This hydrogel adsorbent has great application potential in smart separation. Developing hydrogel adsorbents with both high mechanical property and high adsorption capacity is a big challenge. At the same time, the swelling-adsorption is in conflict. Swelling expands the polymer network and facilitates the exposure of adsorption sites and the diffusion of pollutants. On the other hand, swelling causes the hydrogel to increase in volume and soften, which increases the difficulty of operation and regeneration. Hence, we promote a method of preparation advanced hydrogel adsorbent by high entanglements and low crosslinks. The entanglements work as additional crosslinks, reducing swelling and making the hydrogel tough. Unlike crosslinks, entanglements are like springs, which are flexible and can efficiently transmit and store stress. Therefore, highly entangled hydrogel exhibits high elasticity, low hysteresis, and good fatigue resistance. Abundant carboxyl functional groups are introduced by copolymerizing acrylic acid. The carboxyl groups are not only sites for adsorbing cationic pollutants, but also a smart switch for regulation of swelling. When adsorbing pollutants, the carboxyl groups are deprotonated, and the flexible entanglements allow large swelling of the hydrogel while maintaining good rigidity, which efficiently facilitates adsorption. Compared with highly crosslinked hydrogel with similar polymer content and carboxyl abundance, the adsorption capacity and rate of highly entangled hydrogel increased by more than ten times. While regeneration, the highly entangled hydrogel de-swells efficiently under the tension of entanglements, significantly improving the operability of regeneration. This study provides a novel strategy for developing smart hydrogel adsorbent. [ABSTRACT FROM AUTHOR]

• A 3D rice-like hierarchical nanocomposite was designed by anchoring La species into LDH matrix. • La@MgAl achieved high adsorption capacities for both phosphate and fluoride. • Satisfactory selectivity and reusability of the adsorbent were proved. • Interlayer sorption and inner-sphere complexation were main mechanisms for excellent adsorption performance. • La@MgAl was effective for synchronous phosphate and fluoride remediation in real wastewater. The frequent occurrence of algae boom and skeletal fluorosis has drawn global attention to developing feasible technologies for phosphate and fluoride removal from water bodies. This study reported the synthesis of novel three-dimensional rice-like La@MgAl nanocomposites by anchoring La species into Mg-Al LDH matrix to achieve effective and synchronous phosphate and fluoride capture. Results from multiple detection methods including XRD, SEM, FTIR, and XPS revealed the introduced La cations could serve as a structural inducer to regulate the crystallinity of the La@MgAl composites and rice-like nanocomposite La@MgAl-1 was fabricated under optimal La loading amount. La@MgAl-1 possessed high adsorption capacities for both phosphate and fluoride (101.59 mg/g and 51.03 mg/g, respectively). The effective adsorption performance also sustained even after five adsorption-desorption cycles, indicating favorable reusability. The adsorption mechanism analysis revealed that the presence of unique hydrotalcite-like structure triggered memory effect to exert strong adsorption of P and F anions into the interlayered gallery. Besides, an optimum amount of La species organized on the composite wielded specific anion adsorption to phosphate and fluoride through inner-sphere complexation and ligand exchange. These encouraging results highlight the positive consequence of combining the strategic La species and LDH matrix to render a nanostructured Mg/Al/La ternary metal assembly in which various components are united in a controllable way to exert collective properties for accumulative anion adsorption properties. Besides, this study offered promising candidates for real water purification against phosphate and fluoride pollution. [ABSTRACT FROM AUTHOR]

[Display omitted] • SA/PEI-0.25 aerogel showed high elastic, stability and adsorption performance. • The maximum adsorption capacities of Cr(VI) and Cd(II) were 678.67 and 464.23 mg/g. • The fixed-bed continuous filtration of Cr(VI) and Cd(II) wastewater was realized. • SA/PEI-0.25 aerogel reduced the toxicity of heavy metal ions to rice. • The adsorption mechanisms of Cr(VI) and Cd(II) were investigated. Herein, an elastic polyethyleneimine/sodium alginate aerogel was designed by a one-step freeze-drying method. The 3D honeycomb-like structure endowed it excellent compressibility and plentiful exposed adsorption sites to accelerate Cr(VI) and Cd(II) adsorption. The adsorption processes matched the pseudo-second-order and Langmuir models, and the saturated adsorption capacity for Cr(VI) and Cd(II) was 678.67 and 464.23 mg/g, respectively. The obtained aerogel still expressed superior removal performance for Cr(VI) and Cd(II) even in the coexistent of multiple interfering factors and maintained stable adsorption capacity at least after 5 cycles. Importantly, the elastic cylindrical aerogel (∼0.59 g) could achieve dynamic filtration of industrial wastewater containing Cr(VI) and Cd(II) in fix-bed column system with corresponding effective treatment volume of 4.47 and 3.25 L, respectively. The reasonable mechanisms for the adsorption behaviors of heavy metals on the as-prepared aerogel was investigated via FTIR, XPS and Density functional theory (DFT), which could be attributed to the surface electrostatic adsorption, chelation and reduction effects. Eventually, the ecological assessment verified that eco-friendly SA/PEI aerogel had a powerful auxiliary effect on the anti-fouling growth of rice. Overall, such novel biomass aerogel adsorbent possessed great application potential and theoretical guiding significance for the purification of heavy metal wastewater. [ABSTRACT FROM AUTHOR]

• The FeMnO x /S(IV) system has faster removal speed and higher adsorption capacity for As(III) compared to FeMnO x alone. • The As(III) (1079 µg/L) could be decreased to less than 10 µg/L within 10 min. • The SO 5 •− radicals generated by S(IV) acting as the driving force for the redox cycle between As(III) and Mn(II/III/IV). • The possible mechanism of As(III) oxidation and removal for the FeMnO x /S(IV) system was proposed. • The FeMnO x nanocellulose aerogel broadened the scope of FeMnO x /S(IV) system in engineering applications. Manganese (Mn)-containing composite metal adsorbents are very effective at removing arsenite (As(III)) from contaminated water, however, the low removal speed and oxidation efficiency have limited their further application. In this study, a nonhomogeneous catalytic oxidation–adsorption system was constructed by coupling iron–manganese composite oxide (FeMnO x) with sulfite (S(IV)) to enhance the recovery of oxidative capacity and accelerate the removal of As(III). Experimental results showed that the FeMnO x /S(IV) system decreased the As(III) concentration from 1079 to <10 µg/L within 10 min and almost completely oxidized As(III) to As(V). In contrast, FeMnO x alone removed only 82.4% of As(III) within 30 min, and 60.0% of the adsorbed As(III) was not oxidized. Meanwhile, the adsorption capacity of FeMnO x /S(IV) system for As(III) was considerably higher than that of the only-FeMnO x system (76.5 > 46.3 mg/g). The efficient and fast As(III) removal was attributed to the SO 5 •− radical generated by S(IV) acting as the driving force for the redox cycle between As(III) and Mn(II/III/IV). Several environmental factors (e.g., solution pH and inorganic anions) and the reusability and practicality of FeMnO x were systematically investigated, and the results further confirmed the superiority of the FeMnO x /S(IV) system in As(III) removal. In particular, the proposed FeMnO x nanocellulose aerogel effectively purified arsenic-contaminated groundwater using a fixed-bed column. Thus, FeMnO x –S(IV) coupling is very promising for the purification of arsenic-contaminated water bodies. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • This study investigates the adsorption properties of silver with Po-based molecules. • Ag(1 1 1) provides strong 210Po capture for Po, Po 2 , PbPo, and PbOH except H 2 Po. • The results are important to guide experiments on scavenging 210Po. Recent nuclear power reactor designs propose the use of lead–bismuth eutectic (LBE) as a coolant. However, neutron capture in liquid LBE produces the radioactive nuclide polonium-210 as 210Po and 210Po-based molecules, which must be sequestered via a capture process. While silver has demonstrated a high adsorption capacity for 210Po, the adsorption capacity of silver for the various forms of Po-based molecules remains uncertain. The present study addresses this issue by applying density functional theory to investigate the adsorption properties of Ag(1 1 1) surfaces with Po, Po 2 , PbPo, H 2 Po, and PoOH adsorbates. The results demonstrate that the adsorption capacities of Ag(1 1 1) surfaces for these forms of 210Po reside in the order of Po 2 > PoOH > Po > PbPo > H 2 Po, and all of the adsorption processes are exothermic. In addition, the adsorption processes involved are also characterized based on the calculated density of states. The calculations demonstrate that strongly overlapping Po 6p, O 2p, and Ag 4p states result in the chemisorption of Po, Po 2 , PbPo, and PoOH on Ag(1 1 1) surfaces, while these states do not overlap strongly for the H 2 Po adsorbate, resulting in its physisorption on Ag(1 1 1) surfaces. [ABSTRACT FROM AUTHOR]

The extensive use of tetracycline (TC) as veterinary therapeutics and animal growth promoters has caused human health problems. Some adsorbents have been developed to remove TC, but the adsorption capacity is still unsatisfactory. Here, we synthesized octahedral cuprous oxide nanocrystals (oct-Cu 2 O NCs) by a hydrothermal method at room temperature. Surprisingly, the maximum adsorption capacity of oct-Cu 2 O NCs reached an astonishing amount of 1112.6 mg/g. Adsorption kinetics and isotherm experiments for TC removal were carried out to evaluate its potential as an adsorbent. The key factors like pH and solution ions as well as the mechanism of TC adsorption on oct-Cu 2 O NCs were also studied. The main adsorption process may be that the hydroxyl group (-OH) on the {111} facets surface of oct-Cu 2 O NCs is replaced by the amino group (-NH 2) of TC. The high adsorption capacity is generated by the abundant Cu atoms with dangling bonds on the {111} facets surface and the strong chemical coordination between the -NH 2 of TC and Cu(I). This work provides an alternative with a promising application prospect for the treatment of TC in water. Unlabelled Image • Oct-Cu 2 O NCs with {111} facets were prepared through a simple hydrothermal method. • Oct-Cu 2 O NCs possess excellent tetracycline adsorption performance. • A large number of adsorption active sites are on the {111} facets. • Strong adsorption is generated by the coordination between -NH 2 of TC and Cu(I). [ABSTRACT FROM AUTHOR]

• A cost-effective periclase-based pathway was proposed for adsorbent synthesis. • Novel Mg-La bimetal oxide nanocomposite was prepared. • Optimal urea amount induced 3D needle-like nanostructure. • Superior P and F adsorption capacities were achieved. • Inner-sphere complexation dominated the adsorption mechanism. Phosphate and fluoride are primary culprits of water eutrophication and skeleton fluorosis, respectively, severely threatening the security of aquatic lives and public health. To deal with the aqueous phosphate and fluoride pollution, PC@La nanocomposites were tailor-designed based on low-cost periclase and lanthanum salt via a facile urea hydrothermal method. Results from SEM, XRD, FTIR, XPS analysis revealed the PC@La-1.0 was constructed by Mg-La bimetal carbonated hydroxides with the three-dimensional needle-like nanostructure. Highly effective adsorption capacities for both phosphate (107.34 mg/g) and fluoride (63.11 mg/g) were achieved by PC@La-1.0. The adsorption was pH-dependent, and the optimal pH values for adsorption was 4.0–6.0. Over 80% of initial adsorption capacities remained after four adsorption–desorption cycles, indicating its satisfactory reusability. Superior adsorption selectivity for phosphate and fluoride was proven when co-existing with common ions and organics in solutions and real sewage. Mechanism analysis revealed that the unique structure of Mg-La bimetal carbonate hydroxide structure of PC@La-1.0 promoted an accumulative anion adsorption performance. Mg and La cations on PC@La-1.0 formed strong inner-sphere complexation with target phosphate and fluoride while the internal carbonate and hydroxyl groups contributed to adsorption via ion exchange. This study highlights the novel low-cost method to prepare promising candidates for efficient dephosphorization and defluorination from water. [ABSTRACT FROM AUTHOR]