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In this study, lignin sulfonate-based mesoporous materials (LSMMs) were prepared and applied for removal malachite green (MG) from aqueous solution. Lignin sulfonate- g -poly (acrylic acid- r -acrylamide) was prepared by grafting poly(acrylic acid- r -acrylamide) onto a lignin sulfonate molecule followed by crosslinking. N 2 adsorption/desorption indicated that the corsslinked lignin sulfonate- g -poly(acrylic acid- r -acrylamide) were mesoporous materials. The batch adsorption experiments of MG on LSMMs were carried out to evaluate the performance of the LSMMs. Results revealed that the maximum percentage adsorption of MG on the LSMMs is more than that of MG on the lignin sulfonate-based polymer without grafted copolymer with a maximum difference of 37% in the same adsorption conditions. pH, adsorbent dosage, initial MG concentration and temperature are just the parameters that could exhibit breathing effect to the adsorption process. The adsorption kinetics follows a pseudo-second-order kinetics, intra-particle diffusion is not the only rate-controlling step in the entire adsorption process, and the equilibrium adsorption data could be described well by the Langmuir isotherm equation. The adsorption process is endothermic, spontaneous and random. LSMMs can be used as low-cost adsorbent for refractory cationic organic dye in effluent. [ABSTRACT FROM AUTHOR]

Anaerobic ammonium oxidation (anammox) is an energy saving and environmentally friendly technique for wastewater treatment. Sludge adsorption is an important process after organics enter the anammox reactor. The extracellular polymeric substances (EPS) of anammox sludge play a key role on the activity of anammox. This study utilized Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) to investigate molecular-level compositional characteristics of the stratified EPS of the anammox sludge, and to explore the adsorption preference of each EPS layer to refractory dissolved organic matter (DOM) during anammox treatment. Results showed that the adsorbed component by the tightly bound EPS layer was dominantly composed of lipids and proteins, with nearly 80% of formulas being CHO and CHON. The outer layers (slime, loosely bound-EPS) preferentially adsorbed the compounds with comparatively higher aromatic and unsaturated degrees, with S-containing formulas and lignin being the predominant components. The newly produced formulas in the effluent were inferred to be associated with the anammox treatment performance. The refractory DOM, with smaller molecular weight and high reductive degree, seemed to experience a single adsorption by the stratified EPS, and became part of the anammox sludge. • High removal efficiency shows preferential S-compound adsorption by Anammox EPS. • EPS outer layers show greater adsorptive ability for refractory DOM. • Small molecular weight, high saturated degree DOM formulas show environmental risk. [ABSTRACT FROM AUTHOR]

• P-CSs was preparation through H 3 PO 4 modifying CSs. • 2.The q e of MB on regenerated P-CSs maintained 91% level on native P-CSs after 4 adsorption-desorption cycles. • Electrostatic attraction, ion exchange are involved in adsorption of MB on P-CSs. A novel bio-adsorbent based on H 3 PO 4 -modified corn stalks (P-CSs) was synthesized and used to adsorb methylene blue (MB) from aqueous solution. The successful modification of corn stalks by H 3 PO 4 was verified by using XPS, FT-IR, respectively. Meanwhile, the adsorption performance and the adsorption mechanism of P-CSs were investigated. This novel bio-adsorbent performed stably over a considerably wide pH range of 6.0∼9.0. And electrostatic attraction and ion exchange were involved in adsorption of MB on P-CSs. Furthermore, the adsorption of MB by P-CSs perfectly fitted the Langmuir isotherm model (R 2 = 0.997–0.999) and pseudo second order kinetic model (R 2= 0.999). The q e of MB on P-CSs was 129 mg/g at 308 K by Langmuir model, and thermodynamic study showed that MB adsorption is a spontaneous exothermic process. The regeneration and re-adsorption experiments indicated P-CSs's merit of regeneration with the recovery efficient of 91% after 4 adsorption-desorption cycles. This novel bio-adsorbent prepared in this work could achieve effective removal of MB and could be reused for 4 and more adsorption-desorption cycles for MB removal. [ABSTRACT FROM AUTHOR]

Molecularly imprinted polymers (MIPs) on the surface of iniferter-modified carbon microspheres (CMSs) were synthesized by using dibenzothiophene (DBT) as the template molecule, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the crosslinker. The influencing factors of monomer-grafting process were investigated. The characterizations of structure and morphology suggest that a thin layer of MIPs was grafted on the surface of CMSs under the optimized conditions. The adsorption results show MIPs-CMSs possessed higher binding capacity and selectivity than non-imprinted polymers on CMSs (NIPs-CMSs), and exhibited a good competitive adsorption capacity for DBT. The maximum adsorption capacity of MIPs-CMSs towards DBT reached 88.83 mg g −1 . In addition, the adsorption of DBT on MIPs-CMSs follows Langergren pseudo second order model and Langmuir–Freundlich isotherm. Negative values of the Gibbs free energy, positive values of standard enthalpy and entropy reveal that the adsorption was a spontaneous, endothermic and entropically driven process during 288–318 K. From the regeneration experiments and adsorption results in the real oil, it is concluded that the MIPs-CMSs could be used in deep desulfurization of fuel oils. [ABSTRACT FROM AUTHOR]

The deep removal of quinoline from coking wastewater is a prerequisite for reducing its potential threat to environmental safety. Therefore, it is urgent to develop advanced materials for efficient removal of quinoline in wastewater. In this work, a nitrogen-doped hollow carbon nanosphere/graphene composite aerogel (HCNS/NGA) was prepared by in-situ reduction self-assembly strategy, in which HCNS prevents the agglomeration of graphene oxide (GO) nanosheets, and a special sphere-sheet mutual support structure is formed to ensure the structural stability. As-prepared HCNS/NGA exhibits large specific surface area, hierarchical pore structure, and excellent conductivity. Large cavity inside and hierarchically porous structure that primarily consists of micropores, resulting in high quinoline adsorption performance (138.37 ± 2.58 mg g-1 at 298 K). Furthermore, in a fixed-bed column adsorption system, the partition coefficient at 10% breakthrough reaches up to 35.19 mg g-1 μM-1. More importantly, HCNS/NGA, as a conductive monolithic sorbent, can realize easy solid-liquid separation, as well as efficient regeneration in situ by electrochemically assisted regeneration. After ten regeneration cycles, the adsorption capacity retention is 91.54%. In short, as an efficient adsorbent, HCNS/NGA has an enormous application potential in wastewater treatment. [Display omitted] • Hollow carbon nanospheres/graphene composite aerogel (HCNS/NGA) was synthesized. • The adsorption property of HCNS/NGA was studied by static and fix-bed adsorption. • HCNS/NGA achieves efficient adsorption towards quinoline in water. • HCNS/NGA could be easily separated from liquid phase. • HCNS/NGA could be regenerated in situ by electrochemical assisted device. [ABSTRACT FROM AUTHOR]

[Display omitted] • Li+ is extracted by combining surface imprinting with magnetic technique. • GO and Fe 3 O 4 @C composites were used as a carrier to improve the adsorption of Li+. • A selectivity coefficient between Li+ and Mg2+ shows a good separation effect. In order to effectively extract lithium from salt lake brine, a novel magnetic graphene oxide-based lithium ion-imprinted polymer (IIP-GO/Fe 3 O 4 @C) was developed by combining magnetic separation technology with surface ion imprinting technology. GO/Fe 3 O 4 @C, which is composed of graphene oxide (GO) and Fe 3 O 4 @C, was modified by silane coupling agent KH570 and then grafted with methacrylic acid (MAA). The IIP-GO/Fe 3 O 4 @C achieved excellent Li+ separation performance, including an adsorption capacity of 31.24 mg/g, good regeneration performance (91% of the initial value after six adsorption–desorption cycles), a moderate equilibrium time of about 2 h, and relatively high selectivity against Na+, K+, and Mg2+ of 14.31, 12.05, and 10.9, respectively. These excellent properties are due to the synergistic effect between the construction of adsorption sites brought by the high specific surface area (225.8 m2/g) of GO/Fe 3 O 4 @C skeleton and the particular recognition of Li+ by 2-hydroxymethyl-12-crown ether-4. Therefore, IIP-GO/Fe 3 O 4 @C can be used as a prominent candidate for extracting lithium from salt lake brine. [ABSTRACT FROM AUTHOR]

[Display omitted] • Amino-functionalized graphene oxide aerogel (MGOA) was ingeniously synthesized. • The adsorption property of MGOA was studied by static and fix-bed adsorption. • MGOA achieves efficient adsorption towards quinoline in water. • MGOA can be easily separated from liquid phase. • Performance of MGOA was confirmed by both adsorption capacity and PC. The direct emission of quinoline in coking wastewater has great harm to human health and environmental quality. Therefore, it is urgent to develop advanced materials for efficient adsorption of quinoline in wastewater. In this study, a novel three-dimensional amino-functionalized graphene oxide aerogel (MGOA) was prepared by an acid induction strategy, which triggers the esterification and amidation of graphene oxide (GO) nanosheets and ammonium citrate. This strategy not only improves the chemical stability and mechanical strength of as-prepared MGOA, but also provides a large number of effective adsorption sites to achieve the efficient adsorption towards quinoline. MGOA has the advantages of three-dimensional interconnected hierarchical pore structure, large specific surface area, and low density. When the initial quinoline concentration is 50 mg L−1, the adsorption capacity (q e) of MGOA towards quinoline is as high as 103 mg g−1 at 298 K. More importantly, in the column adsorption system, the distribution coefficient (PC) at 10% breakthrough is 14.16 mg g−1 μM−1, which is the highest level yet reported. MGOA exhibits good reusability and outstanding solid-liquid separation advantage during eight adsorption-desorption cycles. Density functional theory and van der Waals surface electrostatic potential were used to investigated the adsorption behavior of quinoline on aerogel. The binding force between MGOA and quinoline molecule is strong, with an adsorption energy up to −78.68 kJ mol−1. Thus, MGOA is considered as a promising candidate for removing quinoline contaminants from aqueous solutions. [ABSTRACT FROM AUTHOR]

Herein, following the strategy of sustainable, environment protection, circular economy development, carboxylate-modification lignosulfonate polymer (M-LSP) was synthesized from lignosulfonate by solvent-free esterifying with maleic anhydride (MA) by one step, and was used to remove the dyes by adsorption. FT-IR and XPS were used to confirm successful preparation of M-LSP. The result is that: M-LSP is apt to adsorb cationic dye. In single system, the super adsorption performance of M-LSP for methylene blue (MB) is depended on the carboxyl content in M-LSP. M-LSP performs its remarkable adsorption performance for MB stably at pH 7.0 ~ 10.0, and the maximum adsorption capacity of M-LSP for MB is up to 613.5 mg/g according to Langmuir isotherm model. The Langmuir isotherm and pseudo-second-order kinetic models are more suitable to descript adsorption process of M-LSP for MB. In binary and ternary system, the M-LSP adsorbs the cationic dyes simultaneously, but selectively adsorbs MB. M-LSP can effectively remove cationic dyes in simulate dyestuff water. Moreover, the removal percentage of regenerated M-LSP decreases only 8.4% after 4 desorption-resorption cycles. The results indicated that M-LSP could be a candidate for remediation of real printing and dyeing or textile wastewater containing cationic dyes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Graphitic support dimension of ZIF8@C have key influences on phosphate removal. • 2D graphene provides more efficient SSA for ZIF8 anchoring than that of 1D SCNT. • The maximum phosphate adsorption of 491.2 mg g−1 is obtained for ZIF8@rGO-20. • Nanohybrids with a ratio of metal: −OH ≈ 1: 2 afford the highest phosphate removal. • Suppression of SO 4 2− on P adsorption verify the ligand exchange between P and MOF@C. Developing metal–organic framework-incorporated carbon heterostructure (MOF@C) adsorbents with advanced phosphate removal capability is of remarkable significance in satisfying the increasingly stringent wastewater discharge criteria. Nevertheless, the tailored synthesis of MOF@C architectures and related structure-performance modulation remains elusive to date. Herein, we report on the dimensional engineering of MOF@C to prepare ZIF8@single-walled carbon nanotube (SCNT) and ZIF8@reduced graphene oxide (rGO) heterostructures with satisfactory phosphate removal efficiency. The maximum phosphate adsorption capacity of ZIF8@rGO is 491.2 mg g−1, with the largest partition coefficient value of 1900 mg g−1 μM−1 and an initial concentration of 2 mg L−1 under a neutral condition; thus, the prepared heterostructures evidently surpass state-of-the-art adsorbents. The high adsorption capacity is attributable to the two-dimensional graphene support, which provides a more effective surface area for ZIF8 anchoring than that of one-dimensional CNT. Furthermore, phosphate removal on these dimension-engineered MOF@C is examined as a function of pH, system temperature, and coexisting anions. The underlying mechanism is further elucidated via X-ray photoelectron spectroscopy/X-ray diffraction analysis and density functional theoretical simulation; enhanced phosphate removal by ZIF8@rGO is mainly attributable to the ligand exchange between the phosphates and the adsorbent. Our findings can aid the design of multifunctional MOF@C adsorbents for efficient phosphate removal from contaminated waterbodies. [ABSTRACT FROM AUTHOR]

• CF assisted graphene aerogel (CF/N-RGO) was fabricated via self-assembly method. • The adsorption and structural stability of CF/N-RGO were simultaneously improved. • CF/N-RGO exhibited ultra-light density and high specific surface area. • CF/N-RGO showed excellent superhydrophobicity and adsorption capacity (206.38 g/g). • CF/N-RGO was compressible with excellent structural stability. In order to improve structural stability of aerogel, supported N-doped reduced graphene oxide aerogels are prepared by introducing fiber materials (biomass cellulose and carbon fibers) via self-assembly method. Thereinto, N-doped carbon fibers/reduced graphene oxide aerogel exhibits ultra-light density (7.19 mg/cm3), high specific surface area (329.6 m2/g), excellent superhydrophobicity, high adsorption capacity (206.38 g/g), which is superior to most reported cellulose aerogels. Moreover, regardless of multiple heating or squeezing cycles, adsorption capacity of this aerogel is also more than 90 %. In addition, N-doped carbon fibers/reduced graphene oxide aerogel shows good mechanical compressive property and thermal stability, which contributes to high-valued utilization in practice. [ABSTRACT FROM AUTHOR]

• A zirconia-modified resin D280-Zr was developed for the P removal from wastewater. • D280-Zr had brilliant P adsorption performance with efficiency reached 98%. • D280-Zr exhibited superior adsorption selectivity at coexisting competitive anions. • D280-Zr could be reused for more than 6 times with adsorption efficiency above 80%. • D280-Zr fixed bed had application potential to absorb P from sewage. Adsorption of phosphorus by Zr-based materials has attracted more and more attention. However, the use of these materials was still limited due to the influence of coexisting ions and poor regeneration ability. In this study, hydrated zirconia was loaded into anion exchange resin (D280) to develop phosphorus adsorption material (D280-Zr). As a contrast, the phosphorus adsorption material HZO-201 was prepared by hydrating zirconia with large pore diameter anion resin D201. The samples were characterized by scanning electron microscope (SEM) with an EDX (energy dispersive X-ray), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Zirconium was successfully loaded onto the D280 and surface hydroxyl groups on D280-Zr played a significant role. Through batch adsorption experiments, the maximum adsorption amount of D280-Zr was 47.2198 mg P/g at temperature of 30 °C and pH 6−7. Adsorption isotherms could be described by the Langmuir model, and the adsorption kinetics were well described by the pseudo-first-order and pseudo-second-order model. Co-existing ions (Cl−, NO 3 −, HCO 3 −) had minimum effect on adsorption performance with efficiency above 80%. Through six cycles of regeneration, the adsorption efficiency was still above 80%. After treatment with D280-Zr packed bed column, the effluent could meet the A discharge standard in China of P < 0.5 mg/L in wastewater, and the treated water volume reached about 3500 times the bad volume (3500 BV). The results illustrated that D280-Zr was an effective phosphorus adsorption material. [ABSTRACT FROM AUTHOR]

• Three hybrids with different nanostructures are obtained by varying MWCNTs dosages. • ZIF8@MWCNT120 affords the maximum phosphate adsorption capacity of 203.0 mg g−1. • The outstanding performance of hybrid is due to the enhanced Zn-O-P and H-bonds. • High phosphate removal performance was observed in the real wastewater. In this study, ZIF8@MWCNT nanocomposite has been designed throughout in-situ growth of zeolitic imidazolate framework-8 (ZIF8) polyhedron on hydroxylated multi-walled carbon nanotube (MWCNT). In detail, three types of nanocomposites harvesting different nanostructures are obtained by varying the dosages of MWCNTs. Such nanocomposites are assessed as phosphate adsorbents via batch experiments to determine the adsorption capacity, reusability and stability. Among the three types of composites, the ZIF8@MWCNT120 affords the maximum phosphate adsorption capacity of 203.0 mg g−1, which is 0.7–3.7 times higher than those of the other adsorbents at the same adsorption conditions. Experimental characterizations in combination with theoretical calculations reveal that the outstanding performance of ZIF8@MWCNT120 is mainly attributed to the enhanced Zn-O-P interaction and hydrogen bonding. In addition, high phosphate removal performance was observed in the real wastewater (residual effluent Conc. = 0.0–0.45 mg L−1) with initial concentrations of 0.63 mg L−1-6.32 mg L−1, which satisfied the A-level standard of phosphate effluent in China (0.5 mg L−1). This work offers a versatile solution to tailor the adsorption affinity of emerging metal-organic-frameworks (MOFs) toward phosphorous-based pollutants. [ABSTRACT FROM AUTHOR]

• Magnetic carbon nanospheres/graphene composite aerogels (MCNS/NGA) were prepared. • Ammonium citrate was used as reducing agent and nitrogen source for the first time. • The MCNS/NGA exhibit high adsorption capacity and excellent recyclability. • Magnetic separation technology and a continuous adsorption system are employed. Recently, graphene aerogels (GAs) have attracted considerable research attention in oil/water separation owing to their remarkable properties. However, the serious stacking of graphene oxide nanosheets (GO) would lead to low adsorption capacity and poor recyclability. For the first time, with alkaline ammonium citrate as reducing agent and nitrogen source, the point-to-face contact between magnetic carbon nanospheres (MCNS) and graphene sheets was adopted to effectively inhibit the aggregation of graphene sheets. Nitrogen-doped magnetic carbon nanospheres/graphene composite aerogels (MCNS/NGA) were fabricated under weakly alkaline conditions by one-step hydrothermal in-situ electrostatic self-assembling strategy. The aerogels have low density, super-elasticity (up to 95 % compression), high specific surface area (787.92 m2 g−1) and good magnetic properties. Therefore, they exhibit adsorption capacity in the range of 187–537 g g−1 towards various organic solvents and oils, superior to most reported materials to date. In addition, thanks to their good mechanical properties, excellent thermal stability and flame retardancy, they can be regenerated by squeezing, distillation and combustion. More importantly, magnetic control technology can be adopted to realize oriented adsorption and facilitate recycling of organic solvents and oils in extreme environments. [ABSTRACT FROM AUTHOR]

• Magnetic carbon nanospheres (MCNSs) were synthesized. • KOH activation and HNO 3 acidification of MCNSs were carried out. • MCNSs-KH exhibited the best saturated adsorption capacity. • Pore structure and acid–base interaction are the key factors for adsorption. Magnetic carbon nanospheres (MCNSs) dotting with Fe 3 O 4 nanoparticles were synthesized by a simple solvothermal method. Furtherly, KOH activation and HNO 3 acidification of MCNSs were carried out to tune surface structure and property of MCNSs for the sake of adsorption improvement. The results show that both MCNSs and modified MCNSs (MCNSs-KH) have magnetic properties, and can be used as adsorbents for rapid separation and reutilization towards quinoline in coking wastewater. After KOH activation and HNO 3 acidification, the saturated adsorption capacity of MCNSs-KH is improved to 297.21 mg g−1, much better than that of MCNSs (99.43 mg g−1). According to BET and NH 3 -TPD characterizations, KOH activation introduced a large number of pore structures, which significantly increased the specific surface area of MCNSs; HNO 3 acidification further increased the surface acidity of MCNSs, especially C O functional group, which promoted the acid–base interaction with weakly basic quinoline. From the results of adsorption kinetics, isotherm and thermodynamics, the spontaneous and exothermic adsorption process conformed to pseudo-second-order and Langmuir–Freundlich models better. [ABSTRACT FROM AUTHOR]

Application of biochar as an adsorbent for wastewater treatment has obtained a tremendous research interest owning to their low cost and surface functionality. In this research, an iron loaded sludge biochar was successfully prepared through a simple and economical one-step modification hydrothermal method. The iron loaded sludge biochar possesses large amounts of surface organic functional groups (such as hydroxy, carboxyl and aromatic ring, etc.), smaller particle size (about 10 nm) as well as relative higher surface area (82.780 m2 g−1) than of the pristine one. The selective removal of two kinds of antibiotics by the prepared products was demonstrated. Experimental data was fitted to isotherm and kinetic models, and thermodynamic parameters were also calculated. In the single antibiotic system, the maximum adsorption amount of tetracycline (TC) and doxycycline (DOX) could reach 104.86 and 128.98 mg g−1 at 293.15 K, respectively. In the binary antibiotics system, there was an antagonistic effect between TC and DOX. Furthermore, the adsorption of TC was much more inhibited than that of DOX owning to its deferent steric hindrance of molecular structure. Image 10513 • A sludge based biochar was synthesized and modified by one step hydrothermal method. • The influence of loaded iron on the characteristic of biochar was investigated. • The adsorption of antibiotics is dominant by π-π interaction and hydrogen bonds. • There is an antagonistic effect between TC and DOX in the co-adsorption of them. • The steric hindrance leads the competitiveness of TC is weaker than DOX. [ABSTRACT FROM AUTHOR]