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Two sodium alginate-based Pb2+-imprinted thermosensitive hydrogels (SPIT (without ɛ-PL) and SPPIT (with ɛ-PL)) were synthesized, with sodium alginate and ɛ-polylysine (ɛ-PL) as the matrix, N-isopropylacrylamide as the monomer. Characterization with differential scanning calorimeter, Fourier transform infrared spectroscopy, thermogravimetric analyzer, scanning electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy confirmed the aimed structure of the hydrogels. The adsorption capacity of SPIT and SPPIT for Pb2+ was 98.64 mg/g and 153.49 mg/g, respectively. Washing the Pb2+-loaded adsorbent with 10 °C deionized water, SPIT and SPPIT achieved a desorption efficiency of 94.59 % and 97.51 %, respectively. After 10 cycles of adsorption-desorption process, the adsorption capacity and desorption efficiency remained at about 80–88 % of the original ones, expressing excellent reusability. In a mixture containing eight metal ions (Pb2+, Cu2+, Mg2+, Ca2+, Cd2+, Na+, K+, Fe3+), the adsorption capacity of SPIT to Pb2+ was 92.49 mg/g, and that of SPPIT was 102.49 mg/g, much higher than that to the other ions (1.50–11.38 mg/g on SPIT, 9.48–27.45 mg/g on SPPIT), showing excellent adsorption selectivity. The introduction of ɛ-PL enhanced the adsorption capacity, antibacterial ability and stability of the hydrogel, ensuring better application potential in real wastewater. • Two Pb2+-imprinted adsorbents were prepared with sodium alginate as the matrix. • The differential scanning calorimeter test confirmed the reversible thermosensitivity of the adsorbents. • Washing with cold water (5-10 °C) could regenerate the Pb2+-loaded adsorbents. • After 10 cycles of reuse, 80–88 % of the adsorption capacity was remained. • The adsorptive selectivity coefficient of adsorbent was up to 33.99. [ABSTRACT FROM AUTHOR]

The efficiency of saturated Activated Carbon (AC) electrochemical regeneration was evaluated. Reactor configurations in cathodic/anodic process, applied current effect on the properties of AC and Methylene Blue MB-AC interactions and adsorption/desorption mechanisms were studied. The efficiency was measured by adsorption capacity adsorption/regeneration cycles and changes in the adsorbent characteristic were analyzed through FTIR, BET, Optical Microscopy (OM) and SEM before and after the regeneration. The energy consumption was analyzed to assess the economic feasibility. It was found that the electrochemical treatment was efficient in returning the AC adsorption capacity, maximum efficiencies of approximately 79% and 84% were reached when the Carbon Fiber Cloth-AC electrode was subjected to anodic and cathodic currents, respectively, at a current of 0.1 A. In addition, the material demonstrated good stability through adsorption-regeneration cycles by cathodic process, with the material's adsorption capacity being almost totally recovered for 8 consecutive cycles. The removal percentage around 80% was kept after the cycles, with optimal conditions when the electrode was subjected to cathodic currents, NaCI as electrolyte at a current of 0.1 A for 2 h. The characterization techniques provided results that allow to explain the higher and prolonged efficiency of the cathodic current. Furthermore, these reactor configurations achieved an electrical energy consumption of 2.3 and 2.1 kWh kg-1 of material for cathodic and anodic, respectively. These results indicate that the electrochemical is an economical and environmental suitable technique capable of restore carbon adsorbents to be reusable for several water treatment cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] The efficiency of saturated Activated Carbon (AC) electrochemical regeneration was evaluated. Reactor configurations in cathodic/anodic process, applied current effect on the properties of AC and Methylene Blue MB-AC interactions and adsorption/desorption mechanisms were studied. The efficiency was measured by adsorption capacity adsorption/regeneration cycles and changes in the adsorbent characteristic were analyzed through FTIR, BET, Optical Microscopy (OM) and SEM before and after the regeneration. The energy consumption was analyzed to assess the economic feasibility. It was found that the electrochemical treatment was efficient in returning the AC adsorption capacity, maximum efficiencies of approximately 79% and 84% were reached when the Carbon Fiber Cloth-AC electrode was subjected to anodic and cathodic currents, respectively, at a current of 0.1 A. In addition, the material demonstrated good stability through adsorption-regeneration cycles by cathodic process, with the material's adsorption capacity being almost totally recovered for 8 consecutive cycles. The removal percentage around 80% was kept after the cycles, with optimal conditions when the electrode was subjected to cathodic currents, NaCl as electrolyte at a current of 0.1 A for 2 h. The characterization techniques provided results that allow to explain the higher and prolonged efficiency of the cathodic current. Furthermore, these reactor configurations achieved an electrical energy consumption of 2.3 and 2.1 kWh kg −1 of material for cathodic and anodic, respectively. These results indicate that the electrochemical is an economical and environmental suitable technique capable of restore carbon adsorbents to be reusable for several water treatment cycles. [ABSTRACT FROM AUTHOR]

• The continuous adsorptive removal of phenol using low-cost activated carbon was studied. • Effects of electromagnetic field (EMF), and electric potential (EP) in the phenol removal were studied. • EMF enhanced the removal performance of activated carbon electrodes on the aluminum substrate. In this study, we introduce an electrode configuration setup to study the effect of an electromagnetic field (EMF) and electric potential (EP) on phenol removal in a continuous adsorption process. Feed water contaminated with dissolved phenol was exposed to EMF and passed through charged activated carbon electrodes prepared from Phoenix dactylifera (palm tree) biowaste. This study investigated the effects of magnetic field exposure, electric potential, feed salinity, and electrode substrate type. The results revealed that the highest adsorption uptake capacity of 47.2 mg/g was achieved using an aluminum substrate (AS) with EMF at zero salinity. The phenol adsorption kinetics followed a pseudo-second-order adsorption rate and diffusion model, indicating that intraparticle diffusion was the primary rate-limiting mechanism. The increased phenol adsorption uptake capacity brought on by the EMF may result from the improved mass transfer and mobility of the adsorbate and, consequently, the increased effectiveness of the internal diffusion of the pollutants. Finally, a regeneration efficiency of 99 % was achieved using NaOH at a salinity of 5,000 ppm. [ABSTRACT FROM AUTHOR]

[Display omitted] • The leaching effect of albite was sorted as follows: hydrochloric acid > potassium hydroxide > deionized water. • The adsorption of H 3 O+, OH− and H 2 O molecules on the surface of albite resulted in the loose framework of albite. • The H+ and K+ in solution exchanged with Na+ in albite and caused the leaching of Na element in albite. The mechanism of inorganic acid and alkali promoted weathering of albite is still unclear. In this work, the mechanism was investigated through leaching experiments and DFT simulations. The results showed that the leaching effect of albite was sorted as follows: hydrochloric acid > potassium hydroxide > deionized water. The H 3 O+ dehydrogenated by breakage of O–H bond, and then the proton bonded with the O atom to form a silicon hydroxyl group on the surface of albite. The O atom in OH− bonded with the three-coordinated Al atom to form the four-coordinated Al. The H 2 O molecule was adsorbed on the surface of albite by hydrogen bond. Meanwhile, the adsorption of H 3 O+, OH− and H 2 O on the (0 0 1) surface of albite caused the elongation of Si–O and Al–O bonds in the bulk phase, resulting in the loose framework of albite. Compared to the interaction mode of water molecules and albite, the H+ in hydrochloric acid and K+ in potassium hydroxide exchanged with Na+ in albite, which caused that the albite lattice was contracted and expanded, respectively. As a result, the surface of albite was damaged, and further caused the Na element was released from the albite crystal to liquid phase. [ABSTRACT FROM AUTHOR]

The adsorption phenomenon on surfaces is investigated both with and without the presence of an external electric field. A simple interpretation of the adsorption coefficient and desorption time, as they appear in Langmuir's isotherm model, is presented. A model for electrosorption is proposed, which explicitly takes into account the applied external voltage and the reaction field resulting from the adsorbed charges. Both saturation, stemming from the finite density of adsorption sites, and non-saturation regimes are considered. The case of a system in contact with a reservoir of particles is also analyzed for its experimental importance. The model's validity is assessed by analyzing experimental data published by several research groups. A comparative study of the proposed model is conducted in relation to the commonly used pseudo-first and pseudo-second order models. Unlike the latter models, the proposed model allows for the assessment of the impact of the external voltage on the model parameters. The model takes into account ion generation resulting from electrolysis phenomena. [Display omitted] [ABSTRACT FROM AUTHOR]

• Aggregates swell due to the "adsorption-swelling" and "adsorption-filling" effects. • The "adsorption-swelling" effect was most prominent with fraction size 2 ∼ 1 mm. • The "adsorption-filling" effect was most prominent with fraction size < 0.053 mm. Soil aggregates swell when infiltrated by water, and their size can increase in two ways. First, aggregates can attach to one another with water acting as a bridge (i.e., adsorption), and water can enter the aggregate pores (i.e., swelling). This is defined as the "adsorption-swelling" effect. Second, clay can fill the pores of macroaggregates and microaggregates (i.e., filling) when adsorption occurs. This is defined as the "adsorption-filling" effect. However, the size range of aggregates affected by these effects and the extent of their influence on aggregate swelling are still unclear. Therefore, different initial size fractions (5 ∼ 2, 2 ∼ 1, 1 ∼ 0.5, 0.5 ∼ 0.25 and 0.25 ∼ 0.053 mm) of soil aggregates from the black soil zone of Northeast China were studied. The size range of swollen aggregates, the "adsorption-swelling" rate (V) of initial size fractions, and the "adsorption-filling" rate (E) of size fractions < 0.053 mm were measured and calculated in three experimental treatments that involved the following procedures: i) wet-sieving of each initial size fraction in deionized water (WS); ii) wet-sieving of each initial size fraction of air-dried aggregates after they were soaked in absolute ethanol (WS as); and iii) the size fraction < 0.053 mm air-dried aggregates were mixed with each initial size fraction of air-dried aggregates in absolute ethanol and then wet-sieved (WS af). The results were as follows: i) the size fraction 2 ∼ 0.053 mm were swollen. ii) V decreased exponentially with decreasing initial particle size, with a maximum value of 32.30% at a size fraction of 2 ∼ 1 mm; and iii) the "adsorption-filling" effect of size fraction < 0.053 mm was obvious in the size fraction < 2 mm swelling aggregates with a maximum of 29.54%. The "adsorption-swelling" and "adsorption-filling" effects had greater impacts on soils with high contents of the size fractions 2 ∼ 1 and < 0.053 mm. This study provides a theoretical basis for understanding the swelling mechanisms of soil aggregates. [ABSTRACT FROM AUTHOR]

• A modified configuration for the energy-efficient adsorption desalination method was proposed. • Internal heat recovery achieved within the proposed multi-cycle system. • Considerable amounts of cooling production with two temperature levels were delivered. • 20 % rise in SDWP was observed in comparison to a single-cycle configuration. • Full sensitivity analyses of the system parameters were carried out. Due to the drawbacks of conventional methods of desalination, the adsorption desalination system has been introduced as a replacement with several advantages such as capability of using low-grade waste heat, low cost, and production of cooling as its second output. The aim of the paper is to provide a conceptual theoretical framework based on new advanced adsorption desalination and cooling system configured of double-cycle multi-bed dual-evaporator with internal heat recovery. As an innovative approach, the cycles are coupled through integrated equipment, working as a condenser for one of the cycles and a high-pressure evaporator for the other one. System performance is investigated in terms of specific daily water production (SDWP), low and high-pressure cooling capacities (SCPLP and SCPHP), and overall conversion ratio (OCR). It is shown that not only SDWP of the proposed configuration increases by 20% in comparison to the single-cycle multi-bed dual evaporator system, but also it is capable of producing considerable amounts of two grades of cooling water. The proposed configuration with 9.6 m3 of SDWP along with 24 and 25 Rton/ton of high and low-grade cooling capacities could be a suitable alternative to conventional configurations of adsorption desalination. Furthermore, a full sensitivity analysis is carried out by manipulating several system parameters, and the system performance is evaluated. [ABSTRACT FROM AUTHOR]

Selective capture of radioactive 99TcO 4 - from highly alkaline nuclear waste is highly desirable for environmental remediation and waste disposal. However, the combined features of adsorbents with excellent chemical stability and high capture selectivity for 99TcO 4 - have not yet been achieved. Herein, we report an ultra-stable 3D pyridinium salt-based polymeric network (TMP-TBPM) nanotrap with remarkable radiation, acid and base stability for selective capture of ReO 4 - via hydrophobic engineering and steric hindrance, a non-radioactive surrogate of 99TcO 4 -. The batch capture experiments show that TMP-TBPM has high capture capacity (918.7 mg g−1) and fast sorption kinetics (94.3 % removal in 2 min), which can be attributed to the high density of pyridinium salt-based units on the highly accessible pore channels of 3D interconnected low-density skeleton. In addition, the introduction of abundant alkyl and tetraphenylmethane units into the 3D framework not only greatly enhanced the hydrophobicity and stability of TMP-TBPM, but also significantly improved the affinity toward 99TcO 4 -/ReO 4 -, enabling reversible and selective capture of 99TcO 4 -/ReO 4 - even under highly alkaline conditions. This study exhibits the great potential of 3D pyridinium salt-based polymeric network nanotrap for 99TcO 4 -/ReO 4 - capture from highly alkaline nuclear waste, providing a new strategy to construct high-performance cationic polymeric sorbents for radioactive wastewater treatment. [Display omitted] • Robust 3D pyridinium salt-based polymeric network for selective capture of ReO 4 −. • The first example of 3D pyridinium salt-based polymeric network for ReO 4 - capture. • TMP-TBPM has excellent capture performance and high selectivity for 99TcO 4 -/ReO 4 -. • TMP-TBPM can selectively and reversibly capture 99TcO 4 -/ReO 4 - under alkaline conditions. [ABSTRACT FROM AUTHOR]

Abstract The adsorption and desorption behavior of Cr(VI) in membrane capacitive deionization (MCDI) was investigated systematically in the presence of bovine serum albumin (BSA) and KCl with different concentrations, respectively. Results revealed that Cr(VI) absorption was enhanced and the adsorption amount for Cr(VI) increased from 155.7 to 190.8 mg/g when KCl concentration increased from 100 to 200 mg/L in the adsorption process, which was attributed to the stronger driving force. However, the adsorption amount sharply decreased to 90.2 mg/g when KCl concentration reached up to 1000 mg/L suggesting the negative effect for Cr(VI) removal that high KCl concentration had. As for the effect of BSA on ion adsorption, the amount for Cr (VI) significantly declined to 78.3 mg/g and pH was found to be an important factor contributing to this significant reduction. Then, the desorption performance was also conducted and it was obtained that the presence of KCl had negligible effect on Cr(VI) desorption, while promoted by the addition of BSA. The incomplete desorption was obtained and the residual chromium ions onto the electrode after desorption was detected via energy-dispersive X-ray spectroscopy (EDS). Based on above analysis, the enhanced removal mechanism for Cr(VI) in MCDI was found to be consisted of ion adsorption onto electrode surface, the redox reaction of Cr(VI) into Cr(III) and precipitation, which was demonstrated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract Electrochemical oxidation is an effective mean to degrade non-biodegradable organics from the contaminated waters. However, its current efficiency is very low for the low-concentration organic pollutants treatment. In this work, combining with the outstanding adsorption property of CNT and the effective electrocatalytic oxidation performance of β-PbO 2 , we constructed novel layer-by-layer carbon nanotube/PbO 2 anodes (CNT/PbO 2 -3, CNT/PbO 2 -4 and CNT/PbO 2 -5) with high adsorbability to enhance the electrochemical degradation efficiency of low-concentration sodium pentachlorophenate (PCP Na). In electrochemical oxidation tests, the PCP-Na was rapidly enriched in the CNT/PbO 2 film through adsorption/electrosorption and then efficiently degraded in site. The removal efficiency of low-concentration PCP-Na (5 mg/L) on CNT/PbO 2 -4 reached 73.8% after only 5 min of electrolysis, whereas that on pure PbO 2 was only 9.9%. To further clarify the mechanism of improvement of PCP-Na removal on CNT/PbO 2 -4 anode, the generation capacity of·OH radicals, oxygen evolution overpotential, voltammetric charge quantity, interface resistance, and specific surface area of CNT/PbO 2 -4 anode were also assessed and compared with those of other three anodes. Results showed that, in addition to the synergistic effect of adsorption/electrosorption and electrocatalysis, the more active sites, smaller electron transfer resistance and higher direct oxidation capacity of CNT/PbO 2 -4 anode also contributed to improving degradation rate of PCP-Na on CNT/PbO 2 -4 anode. Additionally the electrochemical degradation pathway of PCP-Na was also proposed based on the gas chromatography-mass spectrometry analysis. Finally, CNT/PbO 2 -4 electrode exhibited longer accelerated lifetime of 116 h than pure PbO 2 electrode (91 h). Thus, these findings provide a new anode to improve the removal of low-concentration organic pollutants through combining electrochemical oxidation and adsorption/electrosorption processes. Graphical abstract Image 1 Highlights • A novel layer-by-layer CNT/PbO 2 anode was fabricated. • The degradation efficiency of PCP-Na on CNT/PbO 2 anode was obviously improved. • The low-concentration PCP-Na was enriched on the surface CNT/PbO 2 anode. • Adsorption/electrosorption and electrocatalysis were combined. [ABSTRACT FROM AUTHOR]

Polysaccharide-based hydrogel adsorbents become popular because of their high adsorption capacity and fast adsorption rate, but their low removal rate and poor pH resistance have always been fatal shortcomings. Herein, a feasible strategy was proposed to strengthen the ability of hydrogel adsorbent to remove organic pollutants (i.e., dye) by incorporating natural rectorite (REC) into chitosan- g -poly (2-acrylamido-2-methyl-propane-sulfonic-acid) hydrogel network to form a rectorite-in-polymer network structure. The introduction of less dosage of REC (1.2 wt%) into the hydrogel facilitates to improve its adsorption capacities toward methylene blue (MB) in deionized water, tap water, seawater, Yangtze River water, and Yellow River water (1083.39–1303.49 mg/g); while incorporating higher content of REC (15.8 wt% REC) helps to improve the removal rate (99.6% for MB in real waters), which are greatly superior to commercial activated carbons. The adsorbent keeps high adsorption efficiency in a broad pH range (2–11), and can be reused for >4 times. [Display omitted] • Synthesized chitosan-based hydrogel has a rectorite-in-polymer composite network. • The hydrogel shows high adsorption capacity (1303.49 mg/g) and removal rate (99.6 %). • Removal efficiency keeps high in real waters (Yangtze River, Yellow River, seawater). • The hydrogel's adsorption capacity far exceeds that of commercial activated carbon. • This method is universal to enhance the removal efficiency of hydrogel adsorbent. [ABSTRACT FROM AUTHOR]

• WO 3 –WS 2 decorated polypyrrole nanocomposite are investigated for removing heavy metals and supercapacitor application. • Compared to WO 3 –WS 2 and PPy, WO 3 –WS 2 /PPy showed superior heavy metal removal efficiency. • WO 3 -WS 2 /PPy based electrodes exhibit remarkable supercapacitive properties. • Even after 5000 cycles, WO 3 -WS 2 /PPy exhibits outstanding stability and capacity retention of 81%. Nowadays, developing a simple, economic, and scalable approach for environmental remediation and producing energy storage devices remains challenging. Herein, we report a novel WO 3 –WS 2 decorated polypyrrole (WO 3 –WS 2 /PPy) nanocomposite for the removal of heavy metals, i.e., Cd(II) and Ni(II) and high-performance supercapacitor electrodes. The WO 3 –WS 2 /PPy showed significant improvement in the removal of Cd(II) (95.33%) and Ni(II) (89.95%), while WO 3 –WS 2 and PPy revealed removal efficiency of 87.02 and 77.01% for Cd(II) and 82.97 and 74.66% for Ni(II), respectively. For the competitive adsorption experiment, Cu2+/Zn2+ causes a significant influence, while Na+/K+/Mg2+/Ca2+ exerted less effect on the adsorption of the aforementioned metal ions. The WO 3 –WS 2 /PPy exhibited higher selectivity toward Cd2+ than Ni2+. Along with, the WO 3 –WS 2 decorated PPy based electrode showed a high specific surface area and support conductive networks, which synergistically improved charge storage capability. The WO 3 -WS 2 /PPy-based electrodes exhibit superior electrochemical performance with excellent rate capability, offering the high specific capacitance value of 624 F/g at 3 A/g current density and retaining capacitance stability of 81% after 5000 cycles in 1 M Na 2 SO 4 electrolyte solution. The outcomes of this research infer that WO 3 -WS 2 /PPy is a promising candidate for wastewater treatment and high-performance energy storage applications. [ABSTRACT FROM AUTHOR]

Six water-tolerable metal-organic frameworks (MIL-101(Cr), MIL-100(Fe), MIL-100(Cr), MIL-53(Cr), MIL-96(Al), and UiO-66) were employed for the adsorptive removal of acetic acid from water. UiO-66 exhibited more potential as an acetic acid adsorbent than other five MOFs. UiO-66 was further investigated in the view of adsorption kinetics, isotherm, thermodynamics, and regeneration of the adsorbent. The analysis of film diffusion and intraparticle diffusion model suggested that larger acetic acid concentrations would cause higher effects of boundary layer, and the adsorption process was multiple steps. The kinetic results show that adsorption of acetic acid on UiO-66 fitted to pseudo-second-order model and was controlled by chemical adsorption. The adsorption isotherm of acetic acid on UiO-66 followed Freundlich isotherm, which indicated the presence of heterogeneous surface on UiO-66. The thermodynamic parameters (Δ G , Δ H and Δ S ) were also calculated, confirming that the adsorption of acetic acid on UiO-66 was spontaneously exothermic and decrease of disorder. The regeneration of UiO-66 was also demonstrated by washing with deionized water and ethanol. The adsorption capacity and XRD of UiO-66 did not change significantly even after three cycles. Therefore, UiO-66 can be a promising adsorbent for adsorptive removal of acetic acid from wastewater. [ABSTRACT FROM AUTHOR]

The availability and accessibility of clean and secure water supplies are pressing technological and scientific issues worldwide. As a result of global water constraints, wastewater treatment and reuse are being evaluated as feasible alternatives to fresh water for agricultural irrigation and domestic and industrial purposes. Boron carbon nitride (BCN) nanosheets have been studied intensively in the last decade in batteries, biosensors, and capacitors, and for use as catalysts, and they have recently been used in wastewater treatment. BCN materials, along with their synthesis processes, characteristics, and application areas in water and wastewater treatment, are discussed thoroughly in this paper. Additionally, synthesis processes for ternary BCN compounds, including chemical vapor deposition, ion beam-aided deposition, magnetron sputtering, and pulsed laser deposition, are described. BCN materials have also been explored because of their flexible electrical features, excellent mechanical strength, outstanding unreactivity, and significant stability, which make them appropriate for a range of severe environment applications. Thus, the use of BCN materials as photocatalysts and adsorbents and in electrochemical reduction and capacitive deionization are also discussed thoroughly. The highest ammonia production of 172,226.5 μg/h.mg.cat and faradic efficiency of 95.3% have been obtained using the BCN@Cu/CNT catalyst, whereas the ammonia production and FE values for metal-free BCN are 7.75 μg/h.mg.cat and 13.8%. Moreover, the maximum attained adsorption capacities of BCN nanosheets for Pb2+ and Hg2+ are 210 and 625 mg/g, respectively. Overall, this review indicates that essential work on BCN nanosheets is still needed. Future research should focus on the development of BCN nanostructures to encourage multidisciplinary research. [Display omitted] • BCN nanosheets improved performance for water treatment is summarized. • Synthesis methods for ternary BCN nanosheets are explored. • BCN as photocatalysts, adsorbents, and in electrochemical reduction are discussed. • Metal-loaded BCN nanosheets were elaborated as effective water treatment strategy. • Metal and ammonia production potential of BCN increased with metal modification. [ABSTRACT FROM AUTHOR]

• CPPS-2-18 electrode is fabricated by adsorbing the redox mediator(AR18) into the nanopores of CPPS-2 through electrosorption. • AR18 confined into the nanopores can play crucial role on enhancing the electrochemical properties of CPPS-2-18. • Due to the confined effect, the shuttle behavior of the ions in the electrolyte is inhabited well. • The electrochemical properties of the electrode are improved by confining AR18 into the nanopores. The limitation of low energy density of carbon-based supercapacitors can be broken through introducing redox mediators into the electrolyte. Herein, biomass porous carbon CPPS-2 with a high specific surface area of 1649 m2/g was prepared by KOH activation. Capitalizing on the adsorption property of porous carbon, redox mediator, acid red 18 (AR18), was confined into the nanopores of CPPS-2 to fabricate the CPPS-2-18 electrode. After adsorbing 2.72 mg AR18, the specific capacitance of CPPS-2-18 is 568F/g at a current density of 1 A/g in 1 M H 2 SO 4 , which is as same as that of CPPS-2 in 1 M H 2 SO 4 + 10 mM AR18, however, the rate performance and coulombic efficiency of CPPS-2-18 are higher than those of CPPS-2. The results reveal that the redox reaction in nanopores of CPPS-2-18 is more reversible than that on the surface of CPPS-2. Meanwhile, the symmetric supercapacitor based on CPPS-2-18 achieves a maximum energy density of 23Wh/kg and power density of 6000 W/kg. Besides, the self-discharging behavior of CPPS-2 is restrained by confining AR18 into the nanopores. [ABSTRACT FROM AUTHOR]

• A porous nanofiber membrane with dense distribution of La nanorods was prepared. • Exceptional high utilization ratio of La (0.98). • LPS was easily separated from solution. • The LPS can reduce total phosphorus to less than 10 μg/L in natural lake water. • Phosphate was effectively captured in a wide pH range of 4–10. As phosphate is one of the key causes of water eutrophication, its removal from aquatic ecosystems is essential. Adsorption methods have been widely used to remove phosphate from water bodies. However, most of the adsorbents are unstable and difficult to separate from solution. In this paper, we used a simple electrospinning method to prepare a new, well-dispersed, lanthanum (La)-based porous polyacrylonitrile nanofiber (LPS) with more active sites, which improve its phosphate removal efficiency. The maximum phosphate adsorption capacity on LPS was 218.5 mg P/g (La) (50.4 mg P/g). After complete adsorption, the P/La molar ratio on LPS was 0.98. After 48 h of oscillation, the leakage of La from LPS in deionized water was only 74 μg/L, effectively ruling out secondary pollution of the water-body. Moreover, unlike most adsorbents, LPS has the advantage that it can be readily isolated from water. After treatment with LPS, the total phosphorus (TP) of a water sample from Yangzonghai Lake (Yunnan, China) was reduced to 4.2 μg/L, a value lower than the concentration threshold of eutrophication (10 μg/L) set by the United States Environmental Protection Agency (USEPA) and the first category of the surface water environmental quality standard (10 μg/L) set by China for lakes and reservoirs. [ABSTRACT FROM AUTHOR]

[Display omitted] • CDI technology effectively removed Pb2+ from slightly-polluted water. • The doping of NCDs improved the structural and electrochemical properties. • A monolithic mesh electrode was prepared by electrospinning method. • The Langmuir isotherm and the pseudo-first-order model fitted the electrosorption. • The hydrated radius and valence affected the order of ion adsorption. Capacitive deionization (CDI) technology is an effective method for the removal of Pb2+ from slightly-polluted water. In this study, reduced graphene oxide/nitrogen-doped carbon quantum dots (rGO/NCDs) composites with different NCDs mass ratios were successfully synthesized by hydrothermal method and the preparation process of CDI electrode was optimized by electrospinning method to obtain monolithic mesh-like structure. The results showed that the doping of NCDs improved the structural and electrochemical properties of the composites. rGO/25%NCDs composite possessed well-developed three-dimensional porous structure, high specific surface area (347.65 m2/g) and excellent specific capacitance (284.0 F/g). The prepared CDI electrodes had a fish scale-like graded interfacial structure, and this unique structure made the electrodes exhibit superhydrophilic property. The results of CDI tests showed that the electrosorption capacity of rGO/25%NCDs electrode could reach 19.26 mg/g which was higher than that of the pure rGO electrode and many reported electrodes, when the initial concentration of Pb2+ was 5 mg/L and the voltage was −1.0 V. The adsorption process was consistent with the Langmuir adsorption isotherm and the pseudo-first-order kinetic model. In addition, the study on the competitive adsorption in a co-existed system revealed that the electrosorption capacity was strongly dependent on the ionic valence rather than hydrated radius. [ABSTRACT FROM AUTHOR]

In this study, adsorption of a non-steroidal anti-inflammatory drug such as Diclofenac (DCF) on a commercial carbonaceous aerogel honeycomb monolith (NANOLIT®-NQ40) was ascertained. Based on, the overall design of an adsorption treatment should include a feasible regeneration process for the spent adsorbent. In this work, the adsorption/desorption process was ameliorated by coupling of electrochemical technology (anodic/cathodic polarisation). It was determined that the anodic polarisation enhanced the DCF removal and it was related with the applied voltage and the disposition of the electrodes into the bulk solution. Anodic polarisation at optimal conditions (voltage 0.9 V, electrodes gap 2.5 cm and electrolyte concentration higher than 1 mM) provoked an enhancement (around 30%) in the DCF adsorption rate. The spent aerogel regeneration method for the adsorbed or electro-adsorbed DCF was investigated and cathodic polarisation proved to be a viable regeneration alternative attaining the total regeneration of aerogel. The electro-desorption mechanism seemed to be linked to the generation of repulsive intermolecular forces in the aerogel surface. Finally, the sequential electro-adsorption/electro-desorption process was performed in successive cycles. The results confirmed the feasibility of this strategy, maintaining the efficiency with no structural changes in the monolith after several cycles being the electro-reversible adsorption of pollutants on aerogel a promising technology for the removal of pharmaceuticals from wastewater. [Display omitted] • Removal of Diclofenac (DCF) by adsorption on carbonaceous aerogel honeycomb monolith. • Amelioration of adsorption/desorption process of DCF by anodic/cathodic polarisation. • Optimization of DCF electro-adsorption process: electrode gap, electrolyte, voltage. • Successful sequential electro-adsorption/desorption cycles and monolith regeneration. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel electro-Fenton reactor with porous carbon electrodes and activated carbon (AC). • •OH electrochemical generation was observed in the absence of Fe(II). • Increased electrical conductivity and •OH production at high levels of AC packing. • The effect for simultaneous adsorption and electro-Fenton process was studied. • Promising process for potabilization or wastewater treatment at circumneutral pH. Although electro-Fenton wastewater treatment processes are particularly attractive for their high oxidation power, they are seriously limited by the low pH values that are required for the process, the subsequent neutralization of acid and the addition and removal of iron chemicals. In this work, a study on the design, characterization and performance of a novel electro-Fenton reactor, shows that there is a simultaneous effect that can overcome these limitations when combining activated carbon (AC) adsorption and electro-Fenton effects, while working at same time under neutral pH conditions. The reactor arrangement proposed, involves a cation exchange resin that continuously supplies Fe(II) ions to a chamber containing an AC adsorption bed that is positioned between two concentric porous carbon electrodes. Preliminary experiments assessing the 2e- electrochemical reduction of dissolved oxygen to produce H 2 O 2 in the reactor in the absence of AC, showed that while the concentrations of electro-generated peroxide are, as expected, proportional to the current density, they are inversely related to the current efficiency values. A fluorescence study of hydroxyl radical (•OH) production on the other hand, showed that in the absence and in the presence of iron ions, the corresponding concentration of •OH is 0.800 and 1.057 µM, respectively. Experiments with the reactor using varying amounts of AC, resulted not only in coupled adsorption effects characterized by a removal capacity that increases with the amount of AC, but also in increased electrical conductivity and higher electro-Fenton activity that is probably related to an improved electrical contact between the AC particles and the polarized carbonaceous electrode surface. The performance of the electro-Fenton reactor proposed in this work, was finally evaluated in terms of the removal of a model pollutant dye in both synthetic and real secondary effluents using different AC packed levels. Consistent with previous experiments, the fully compacted AC presented the higher removal rates due to the simultaneous effect of the adsorption of the pollutant and the coupled electro-Fenton degradation process. [ABSTRACT FROM AUTHOR]

Salt-triggered switchable solubility of polymer from water-soluble flocculant to solid-state adsorbent offers possibilities to overcome the limitations of industrial flocculation processes such as narrow flocculation window and high polymer residuals at flocculant overdose. After flocculation and sedimentation, the clarified saline wastewater can be readily recovered and reused for the next dyeing procedure while retaining high-quality colour reproduction. [Display omitted] • Salt-responsive flocculant was integrated by highly charged and hydrophobic groups. • Flocculant shows sensitive switchable phase separation in response to salt stimuli. • Dye flocculation to adsorption transition can be achieved in saline dyeing bath. • Flocculation window was dramatically broadened in high salinity wastewater. • Salt reclamation and reuse can be achieved using salt-responsive flocculant. Herein, a new salt responsive starch flocculant (SSF) via starch etherification with butyl glycidyl ether (BGE) and 2-chloro-4,6-diethylamino-[1,3,5]-triazine (CDAT) was reported as highly salt-responsive polymer. The resulting polymer exhibits a reversible switch from dissolution to precipitation in response to slight external salt stimuli due to the integration of highly charged CDAT moiety. The extent of phase separation, relative solubility and residual polymer in water solution could be precisely modulated by changing the salt concentration and the type of counter ions. The results demonstrated that dyes removal is salt dependent, and that the addition of inorganic salt leads to a pronounced broadening of flocculation window. The as-prepared polymers experience an obvious transition from flocculation to adsorption processes with an increasing salt concentration from 0 to 100 g/L due to the salt-triggered switchable solubility of SSF. Two different mechanisms combined the coagulation and adsorption may be involved in dye decolourization from saline reactive dyeing effluents. The beneficial effect of salt-sensitive flocculant was found to be more significant in reuse of saline wastewater for fabric dyeing, in which the flocculant residuals are significantly low (less than 10.9%). After flocculation and sedimentation, the clarified saline wastewater can be readily recovered and reused three times while retaining high-quality colour reproduction. The salt-driven switchable solubility of polymer from water-soluble flocculants to solid-state adsorbents offers a possibility to overcome the limitations of industrial flocculation processes, such as a narrow flocculation window and high polymer residuals at flocculant overdose. [ABSTRACT FROM AUTHOR]

• The adsorption of diclofenac potassium onto modified soybean hulls was evaluated. • The thermal treatment was studied by thermogravimetric analysis and residence time. • The experimental data fitted pseudo-first order and Sips models. • The adsorption mechanism occurs through hydrogen bonds and π-π interactions. • The modified soybean hulls presented a maximum adsorption capacity of 96.88 mg g−1. Because Diclofenac potassium (DCF-p) is a drug that is easily accessible and widely consumed worldwide, it is often identified in water monitoring samples. Wastewater treatment has not been able to remove it completely, and for this reason traces reach the surface and groundwater, causing an impact on non-target organisms. In this sense, adsorption is highlighted as a simple and usually efficient process. Soybean hulls are residues generated in large quantities, often disposed of in landfills. For this reason, their use as adsorbent becomes interesting. However, no study to date has evaluated modifications of such residue in order to remove drugs from water. Thus, the objective of this study was to evaluate the adsorption capacity of the soybean hulls after chemical and thermal treatment in the removal of DCF-p. In the adsorption tests, it was found that the increase in pH from 5 to 9 caused a small reduction in the adsorption capacity, however the effect of the ionic strength showed that the dissolved salt ions acted as co-adsorbents, favoring adsorption. Kinetic data demonstrated rapid adsorption, with equilibrium at 180 min and adsorption capacity of 17.27 mg g−1. The experimental data adjusted to the pseudo-first-order model, and the intraparticle diffusion model suggested a multi-stage process. The adsorption isotherms were adjusted to the Sips model, revealing a maximum adsorption capacity of 96.88 mg g−1 at 308 K. The thermodynamic parameters indicated a spontaneous and favorable process for all temperatures studied, with an exothermic reaction controlled by physisorption. Lastly, it was found that the adsorption of DCF-p occurred by π-π interaction and hydrogen bonds. [ABSTRACT FROM AUTHOR]

Pb2+ adsorption onto activated carbon was studied as a function of the different liquid medium during batch adsorption process without shaking/agitation of flasks (where adsorbate and adsorbent coexist). As liquid medium deionized water (DW) enhanced with gases bulk nanobubbles (bNBs) was used. The adsorbent material used was activated carbon from potato peels. The maximum Pb2+ adsorption capacity (Q m) was 9 mg/g in the case of adsorption process in DW without agitation, whereas the respective Q m was 94 mg/g by using DW-bNBs as medium without agitation. It was also found that Q m increased to 171 mg/g in the adsorption process with DW-bNBs and agitation (150 rpm). This finding was the start point of a new experimental design where after re-agitation (intense shaking of 225 rpm) of the respective experimental case (94 mg/g), the final Q m was 163 mg/g i.e. very close to the one corresponding to simultaneous adsorption and agitation from the beginning. The results are analyzed and discussed intensively to lead in several important implications on the influence of bNBs to the bulk solute mass transfer. Based on our experimental equilibrium data a modified-Langmuir equation was developed, applied and proposed so as to better simulate the whole (complicated) process. [ABSTRACT FROM AUTHOR]

In this study, the effects of different operating conditions on the salt removal from brackish water by dry and fresh Scenedesmus obliquus (S. obliquus) were investigated to explore the mechanisms of algae biological desalination process. It was identified that, within only 30 min contact time, the salt removal increased with the increasing salinity, which was probably due to the higher NaCl concentration gradient from the bulk solution to the algae surface. Compared to other study with a longer algae cultivation period (16 days), this study demonstrated that both adsorption and absorption contributed to the NaCl removal, but adsorption played a more significant role (two thirds of the NaCl removal). The full adsorption can be reached within a relatively short period (1–30 min), and the salts removed by absorption is negligible when the contact time was short. The Langmuir isotherm adsorption model can accurately predict the NaCl adsorption, which indicated the formation of a single molecular layer on the algae surface. The FT-IR analysis further demonstrated different functional groups on the cell wall of S. obliquus can effectively combine the Na+ and Cl−. Overall, the fresh algae showed much faster adsorption kinetics. The results of this study showed promise for the search of alternative desalination technology with an environmentally friendly algae-based biological system. • Systematic study of mechanisms of algae biological desalination process • Salt removal by adsorption process rather than absorption process • Performance comparison between dry and fresh algae • Adsorption mechanism analyzed by isotherm adsorption models and FT-IR analysis [ABSTRACT FROM AUTHOR]

Mixed mode chromatography of RC membrane with high protein uptake to targeted protein. • A simple approach for orthogonal design of ligands for MMC was developed. • Copolymer layer containing thiolactone was grafted onto RC. • Thiolactone was modified via "amine-thiol-ene" reaction to introduce ligands. • The obtained RC-HIC/IEC RC-RPC/IEC adsorber showed high protein uptake. • Surface bifunctionlization using thiolactone chemistry was successful. Mixed-mode membrane chromatography (MMC) is an effcient separation technology for protein purification. However, tedious preparation methods and difficulty on ligand density control for its stationary phase limit the application of MMC. Herein we explored a one-pot multistep reaction based on the thiolactone chemistry as a platform for membrane surface modification design toward mixed mode membrane adsorbers. The regenerated cellulose (RC) membrane was modified by the atom transfer radical polymerization (ATRP) of styrene-thiolactone (St-Tla), followed by the amine-thiol-ene conjugation. N-butylamine/methacrylic acid and octylamine/methacrylic acid were selected as the modifier to prepare two different mixed mode membrane adsorbers, RC-HIC/IEC (hydrophobic/ion-exchange) and RC-RPC/IEC (reversed phase/ion-exchange). SEM, FT-IR and XPS results showed that the membrane adsorbers were successfully prepared. The RC-HIC/IEC membrane had a statistic adsorption capacity of 73.5 µg/cm2 for human immunoglobulin G (IgG) under the conditions of pH = 8 and 0.5 mol/L NaCl in PB buffer. The RC-RPC/IEC membrane showed a capacity of 70 µg/cm2 for α-chymotrypsin (α-CTP) under the conditions of pH = 6.5 in PB buffer. The feasibility of tethering multi functions onto membrane surface via the thiolactone chemistry was demonstrated in this work. [ABSTRACT FROM AUTHOR]

Three-stage operation system (3S A–C system) combining adsorption and CDI is efficient in recovering liquid fertilizers from wastewater and is a promising technology for simultaneously addressing nutrient crises and environmental pollution. • Hydrogel adsorbents have good separation ability for metal cation and anion. • Hydrogel adsorbents showed little removal of nutrients. • 3S A–C system was presented for nutrient recovery and wastewater treatment. • Plants using recovered liquid fertilizers revealed excellent values. The recovery of nitrogen (N) and phosphorus (P) from wastewater is of great importance in addressing the global nutrient crisis. The limitations of existing methods require the development of effective technology. Here, two different hydrogel adsorbents were fabricated with good separation ability for metal cation (M+) and metal anion (M−) but showed little removal of nutrients. Based on the materials, a novel three-stage operation system combining adsorption and capacitive deionization (CDI) technology was presented for nutrient recovery and wastewater treatment. In the first two stages, mixed metals in wastewater were successfully separated (Cu2+: 144.6 mg/g; Cr 2 O 7 2−: 167.0 mg/g), and nutrients were retained (N and P < 1 mg/g). In the third stage, the residual trace metal ions in the solution were removed (2.0 mg/L to N/A), and the nutrients were enriched through electroadsorption and desorption processes by CDI. Plants using recovered liquid fertilizers revealed similar values for height, root length, and chlorophyll compared with those obtained using actual fertilizers. The results indicated that this novel three-stage operation system (3S A–C system) combining adsorption and CDI is efficient in recovering liquid fertilizers from wastewater and is a promising technology for simultaneously addressing nutrient crises and environmental pollution. [ABSTRACT FROM AUTHOR]

The sequestration of Cs on nanotunnel structured Na-palygorskite was investigated under aerobic conditions combining batch adsorption and spectroscopic approaches. The effects of pH, background electrolyte, humic acid (HA) and temperature on Cs sequestration were examined. Palygorskite showed superior sequestration performance for Cs compared with other common minerals without structural tunnels. The sequestration of Cs on palygorskite was dependent greatly on ionic strength and slightly on pH, the adsorbed Cs was hardly desorbed by deionized water but NH 4 Cl solution, indicating that the sequestration of Cs+ on Na-palygorskite was mainly dominated by ion exchange, and the size-matched nanotunnel structure of palygorskite played a significant role in Cs sequestration. Coexisting alkali metal ions showed great influence on Cs sequestration, and potassium with a larger size strongly competed with Cs due to the more notable steric hindrance. The addition of HA altered the path of Cs sequestration, when HA was introduced before Cs, the attachment of HA on surface inhibited Cs sequestration by blocking the access to the nanotunnels. These results are essential for understanding the environmental fate and risk of Cs and provide a basic reference for an effective sequestration remediation strategy for environmental Cs contaminants. Unlabelled Image • The adsorption of Cs on nanotunnel structured Na-palygorskite was investigated. • Palygorskite shows superior sequestration to Cs comparing with other minerals. • Size-match nanotunnel plays critical role in Cs sequestration due to steric effect. • The results are essential for understanding the environmental fate and risk of Cs. [ABSTRACT FROM AUTHOR]

Continuous online ATR-FTIR spectroscopy in combination with two-dimensional (2D) correlation analysis can be used as a unique tool to explore the xanthate adsorption mechanism in ZnS-Pb(II)-xanthate system by providing real-time kinetic monitoring. • Continuous online in situ ATR-FTIR technique was used to study xanthate adsorption. • The mechanism of Pb(II) activation for ZnS was evaluated by 2D correlation analysis. • Both the xanthate adsorption rate and amount were enhanced by Pb(II) activation. • The KHX adsorption on ZnS and Pb-ZnS followed pseudo first order kinetic model. Zinc sulfide (ZnS) is an important and widely used semiconductor material. To improve the flotation efficiency of zinc minerals and explore corresponding mechanisms has been a central topic of flotation technology and flotation chemistry. ZnS with a high purity and a large surface area was synthesized using zinc nitrate as a zinc source and sodium sulfide as a sulfur source in the laboratory. The synthetic ZnS was then activated with lead nitrate in order to understand involving mechanism and consequently improve its flotation efficiency with xanthates. The adsorption of heptyl xanthate (KHX) at the surface of ZnS and Pb(II) activated ZnS were examined as a function of time using continuous online in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The two-dimensional IR correlation analysis indicates that lead xanthate and zinc xanthate coexisted on the Pb(II) activated ZnS surface and lead xanthate formed prior to zinc xanthate at the surface of Pb(II) activated ZnS. The activation by lead ions increased the adsorption amount and rate constant of KHX. The KHX adsorption onto both ZnS and Pb(II) activated ZnS obeys the pseudo first order kinetic model and the desorption with deionized water is negligible after 20–30 min. [ABSTRACT FROM AUTHOR]