Maximum Equilibrium Adsorption Capacity Research Articles

Nano-Silver-Loaded Activated Carbon Material Derived from Waste Rice Noodles: Adsorption and Antibacterial Performance.

This study demonstrates, for the first time, the conversion of waste rice noodles (WRN) into a cost-effective, nano-silver-loaded activated carbon (Ag/AC) material capable of efficient adsorption and antibacterial activity. The fabrication process began with the conversion of WRN into hydrothermal carbon (HTC) via a hydrothermal method. Subsequently, the HTC was combined with silver nitrate (AgNO3) and sodium hydroxide (NaOH), followed by activation through high-temperature calcination, during which AgNO3 was reduced to nano-Ag and loaded onto the HTC-derived AC, resulting in a composite material with both excellent adsorption properties and antibacterial activity. The experimental results indicated that the incorporation of nano-Ag significantly enhanced the specific surface area of the Ag/AC composite and altered its pore size distribution characteristics. Under optimized preparation conditions, the obtained Ag/AC material exhibited a specific surface area of 2025.96 m2/g and an average pore size of 2.14 nm, demonstrating effective adsorption capabilities for the heavy metal Cr(VI). Under conditions of pH 2 and room temperature (293 K), the maximum equilibrium adsorption capacity for Cr(VI) reached 97.07 mg/g. The adsorption behavior of the resulting Ag/AC fitted the Freundlich adsorption isotherm and followed a pseudo-second-order kinetic model. Furthermore, the Ag/AC composite exhibited remarkable inhibitory effects against common pathogenic bacteria such as E. coli and S. aureus, achieving antibacterial rates of 100% and 81%, respectively, after a contact time of 4 h. These findings confirm the feasibility of utilizing the HTC method to process WRN and produce novel AC-based functional materials.

Copper supported Dowex50WX8 resin utilized for the elimination of ammonia and its sustainable application for the degradation of dyes in wastewater

To obtain high efficient elimination of ammonia (NH4+) from wastewater, Cu(II), Ni(II), and Co(II)) were loaded on Dowex-50WX8 resin (D-H) and studied their removal efficiency towards NH4+ from aqueous solutions. The adsorption capacity of Cu(II)-loaded on D-H (D-Cu2+) towards NH4+ (qe = 95.58 mg/g) was the highest one compared with that of D-Ni2+ (qe = 57.29 mg/g) and D-Co2+ (qe = 43.43 mg/g). Detailed studies focused on the removal of NH4+ utilizing D-Cu2+ were accomplished under various experimental conditions. The pseudo-second-order kinetic model fitted well the adsorption data of NH4+ on D-Cu2+. The non-linear Langmuir model was the best model for the adsorption process, producing a maximum equilibrium adsorption capacity (qmax = 280.9 mg/g) at pH = 8.4, and 303 K in less than 20 min. The adsorption of NH4+ onto D-Cu2+ was an exothermic and spontaneous process. In a sustainable step, the resulting D-Cu(II)-ammine composite from the NH4+ adsorption process displayed excellent catalytic activity for the degradation of aniline blue (AB) and methyl violet 2B (MV 2B) dyes utilizing H2O2 as an eco-friendly oxidant.

Carbonation of waste concrete: An effective and green strategy for enhancing its heavy metals removal from wastewater

Water pollution, especially Pb2+, Cd2+, Co2+, and Ni2+ released from industrial and mine wastewater, harms human health and is a global environmental concern. At the same time, the effective disposal of waste concrete originating from constructs is a global challenge. In this study, carbonated recycled concrete powder (CRP) is efficiently prepared by carbonizing waste concrete powder, which not only might enhance its adsorptive performance but also sequestrate CO2 in the form of mineral carbon. Characterization techniques revealed CRP forms calcium carbonate and highly polymerized silica gel. Batch adsorption experiments indicate that the CRP is found to have strong adsorption properties. The maximum equilibrium adsorption capacities calculated by the Langmuir model were determined as 997.03, 199.56, 148.85, and 76.69 mg/g for Pb2+, Cd2+, Co2+, and Ni2+, respectively, outperforming most waste concrete and industrial wastes reported. The adsorption mechanism mainly includes electrostatic interactions, precipitation, and ion exchange. This study proposes a method to synthesize low cost, good performance, high chemical stability, and facile preparation adsorbent using waste concrete powder, with promising applications in wastewater treatment.

Coal gasification fine slag derived porous carbon-silicon composite as an ultra-high capacity adsorbent for Rhodamine B removal

The extensive release of industrial solid wastes and organic dyes has led to severe environmental pollution, underscoring the urgent need to recycle these solid wastes and to remove the dyes. Herein, a porous carbon-silicon composite (PC-SiO2) is synthesized using coal gasification fine slag (CGFS) as a precursor via an alkali (KOH) activation and an acid (HCl) etching process, and used as an adsorbent for the Rhodamine B (RhB) removal. The as-synthesized PC-SiO2 possesses an ultra-high specific surface area of 1275.63 m2/g, a large pore volume of 0.26 cm3/g, and enriched reactive functional groups (e.g., Si-OH and –COOH). Due to these features, the actual adsorption capacity and removal ratio of the PC-SiO2 for RhB were as high as 1383.72 mg/g and 92.25 %, respectively, at 298.15 K and pH = 7. Further studies indicate that the adsorption of RhB on PC-SiO2 fits both the pseudo-second-order kinetic model and the Langmuir model, with the maximum equilibrium adsorption capacity being 1388.89 mg/g as predicted by the Langmuir model. The adsorption process involves the electrostatic attraction, hydrogen bonding, π-π interaction, and pore-filling mechanism. This work not only offers a novel approach for removing organic dyes from industrial wastewater but also provides an effective strategy for producing high-value-added materials from industrial solid wastes.

Construction and evaluation of biomass-modified mesoporous silica nanoparticles as enzyme-responsive and pH-Responsive drug carriers for the controlled release of quercetin

This study constructed a biomass-modified mesoporous silica nanoparticle with enzyme-responsive and pH-responsive properties. The nanoparticles were used to evaluate the loading and release capacities of quercetin (QU). The multifunctional nanoparticles (MSN@CMCS-HA) were constructed by using hyaluronic acid (HA) and carboxymethyl chitosan (CMCS) as shells and mesoporous silica nanoparticles (MSN) as cores. The carrier's structure and properties were evaluated utilizing zeta, FTIR, TGA, XPS, XRD, BET, SEM, and TEM. The drug adsorption test revealed that the maximum equilibrium adsorption capacity of MSN@CMCS-HA for QU was 314.4 mg/g. In vitro drug release demonstrated that, under the influence of hyaluronidase (100 μg/mL) and pH of 5, the high drug release rate (63.73 %) was achieved. In addition, hemolysis and CCK8 tests confirmed the high biocompatibility of MSN@CMCS-HA. Consequently, MSN@CMCS-HA exhibited promising potential as an enzyme-responsive and pH-responsive drug carrier.

Robust, all-state superhydrophobic-superoleophilic coating for ultrafast selective dye adsorption and oily wastewater purification

Superwettable surfaces have high application potential in liquid separation and dye adsorption, but considerable challenges remain in separately and quickly removing different contaminants in industrial wastewaters such as effluents from textile dying and wool scouring processes. Herein, a robust, all-state superhydrophobic-superoleophilic (SHP-SOI) composite coating was fabricated, using cobalt 2-methylimidazole nanoparticles (ZIF-67 NPs), polydimethylsiloxane (PDMS) and octadecylamine (ODA), and applied to various substrates via a facile two-step dip-coating method. The ZIF-67/PDMS-ODA coated fabrics turned superhydrophobic with a water contact angle (WCA) of over 150°, and oils could easily spread into the fabric with an oil contact angle (OCA) of 0° either in air or water. Owing to the synergistic effect of the coating components, the coating showed ultrafast and repeatable adsorption to anionic dyes (e.g. methyl orange, MO) with the maximum equilibrium adsorption capacity of 205.7 mg/g (MO concentration 100 mg/L, pH = 3). More importantly, 97.9 % of MO was adsorbed in only 5 min and the adsorption reached equilibrium in 30 min. In addition, owing to the coating’s strong affinity toward different oils, the treated fabrics could efficiently separate/adsorb oils from oil contaminated dye solutions. This all-state SHP-SOI coating was robust and could withstand various severe treatments without losing its original wettability and dye/oil adsorption/separation capability; it also exhibited heat induced self-healable property.

Improvement of agave bagasse hydrolysates processing under a biorefinery approach

SummaryThe economic viability of producing second-generation bioethanol from agave bagasse (AB) is influenced by the presence of phenolic compounds in the hydrolysates used during fermentation. These compounds substantially constrain the growth in yeasts that convert sugars into bioethanol, thus becoming a limitation for the process. In this study, it was proposed to select an effective adsorbent matrix to remove and recover phenolic compounds from AB hydrolysates. The related adsorption phenomena and processes were described and characterized. Four adsorbents were examined, including activated carbon (CA), as well as three polymeric matrices (MN-102, ADS-800EP, and SP825L). The adsorption parameters, such as maximum equilibrium adsorption capacity (qmax) and percent desorption, were determined through adsorption–desorption experiments in batch systems. Additionally, the impact of removing phenolic compounds on bioethanol yield was evaluated and the potential use of the recovered phenols as biopesticides against plant pathogens, such as fungi and nematodes, was explored. The results showed that activated carbon has a higher phenol adsorption capacity (qmax = 118.1 mg/g) but a lower desorption capacity (59.46 %), meanwhile, the MN-102 matrix displayed comparable adsorption characteristics and superior desorption capacity (95.81 %), rendering it the most appropriate for the process. Subsequently, the detoxification of the AB hydrolyzate, by phenolic compounds remotion, on bioethanol yield was assessed and resulted in a significant increase (3.5-fold). Finally, the fungicidal potential of the recovered phenolic compounds was evaluated on Fusarium oxysporum and Alternaria alternata, while the nematicidal activity was tested on Meloidogyne incognita. The phenolic compounds exhibited high antifungal activity against F. oxysporum (73.91 %) and moderate activity against A. alternata (40 %), in comparison to the positive control. Moreover, they showed very high nematicidal activity, causing 91.23 % mortality in M. incognita. These findings allow to conclude that incorporating the adsorption stage not only enhances bioethanol yields but also enables the efficient recovery of potentially valuable molecules.

A bifunctional Zn(II) coordination polymer for fluorescence recognition towards hazardous matters and its high adsorption removal of dye pollutant

In this work, a novel Zn(II) coordination polymer (denoted as Zn-CP) was constructed by the mixed ligands of 6-(3′,4′-Dicarboxy phenoxy)isophthalic acid (H4L) and 4,4′-bis(imidazolyl)biphenyl (bib) under solvothermal method. And based on the Zn-CP, the surfactant agent sodium dodecyl sulfate (SDS) was further introduced into the structure, thus obtaining the Zn-CP(S) which possessed the same phase but a smaller size compared with the Zn-CP. Interestingly, the Zn-CP(S) presented a significantly ameliorated fluorescent intensity, about 4.36 times higher than that of the Zn-CP prepared in the absence of SDS. Taking advantage of the improved fluorescence trait of the Zn-CP(S), a fluorescence recognition towards hazardous matters was further carried out. The results showed that Zn-CP(S) could simultaneously recognized for Hg2+, Cr2O72− and a broad range of hazard nitroaromatic explosives with the satisfactory limits of detection (LODs). In addition, Zn-CP could also be used as a recyclable adsorbent to remove methyl orange (MO) in aqueous medium. The maximum equilibrium adsorption capacity of Zn-CP for MO was 61.01 mg/g, and the adsorption mechanism could be attributed to the weak inter-molecular interaction involved π-π stacking and hydrogen bonding between Zn-CP and the MO molecule. Therefore, the bifunctional material has potential application prospects in fluorescence recognition and adsorption.

A novel porous layered K2Ti8O17 for capturing MB and Cu(Ⅱ) in wastewater

Appropriate structural design engineering is an effective method to achieve high adsorption performance, and optimizing the architecture to meet the desired properties remains challenging for adsorbents. Herein, a novel porous layered K2Ti8O17 (PLKTO) formed by interweaved nanowires has been successfully synthesized using MAX phase Ti2AlN and g-C3N4 as the precursors. The K2Ti8O17 nanowires consisted of numerous interconnected pores in a network-like distribution configuration, with a diameter of approximately 20 nm and a length exceeding one μm. Attractively, the PLKTO exhibited fast kinetics, large adsorption capacity, and excellent reusability toward methylene blue (MB) and Cu2+ adsorption. The maximum equilibrium adsorption capacity of MB and Cu2+ was 95.00 mg/g and 330.75 mg/g, with equilibrium times of ∼18 min and ∼25 min, respectively. The adsorption mechanism unveiled that the elimination of MB and Cu2+ was dominated by the pore-filling effect, electrostatic interaction, hydrogen bond, and surface complexation. Additionally, the PLKTO enjoyed highly selective for Cu2+ while investigating competitive adsorption behaviors in binary systems and real-world applications in various water matrices. These results indicated that the PLKTO revealed appealing application prospects for treating wastewater and pollutants and provided methodological guidance for design engineering in fabricating porous and layered structures.

Highly efficient and stable adsorption of lithium from brine with microcapsules containing 1-phenylazo-2-naphthol and trioctylphosphine oxide.

Lithium extraction from salt lake brine is still challenging due to the existence of similar elements, e.g. sodium. In the present work, polysulfone (PSF) microcapsules containing 1-phenylazo-2-naphthol (HS) and trioctylphosphine oxide (TOPO) as extractants were successfully prepared by microfluidic technology for the separation of Li+ from brine with Li+ and Na+. The morphology, composition, and structure of HS-TOPO-based microcapsules were characterized systematically. The results showed that microcapsules consisting of 20 wt% (m m-1) polysulfone and 80 wt% (m m-1) 1-phenylazo-2-naphthol-trioctylphosphine oxide as the extractant, which was labeled as PSF/HS-TOPO-2/8, exhibited the best performance for Li+ adsorption. The separation factor (SF) of Li+ over Na+ is up to 653 and the adsorption capacity for Li+ in the simulated brine could reach 3.67 mg g-1 for microcapsules PSF/HS-TOPO-2/8, which demonstrated that Li+ can be separated with high selectivity. Besides, the kinetic results demonstrated that the adsorption followed quasi-secondary adsorption kinetic models, indicating that the adsorption mechanism of lithium by microcapsules involved chemisorption. After ten cycles of adsorption-elution, the maximum equilibrium adsorption capacity still remained at 87%. All these results demonstrate that PSF/HS-TOPO-2/8 microcapsules can be used as an efficient adsorber for the adsorption of Li+ from brine with high selectivity and stability.

Adsorption and reduction of Cr(VI) by N, S co-doped porous carbon from sewage sludge and low-rank coal: Combining experiments and theoretical calculations

Herein, a novel N, S co-doped porous carbon (S5C5-AC) for Cr(VI) removal was prepared by co-hydrothermal carbonization (HTC) of sewage sludge (SS) and low-rank coal (LC) combining with KOH modification. The results showed that S5C5-AC had excellent adsorption performance on Cr(VI), and lower pH value, higher initial concentration and longer contact time were beneficial for Cr(VI) adsorption. The adsorption kinetics and isotherms revealed that Cr(VI) adsorption by S5C5-AC was homogeneous and dominated by chemisorption. The adsorption isotherm showed that the maximum equilibrium adsorption capacity of S5C5-AC for Cr(VI) was 382.04 mg/g at 25 °C. Furthermore, the results showed that the main mechanisms for Cr(VI) removal were the pore filling, electrostatic interaction and reduction. Moreover, the electron transfer mechanism during the adsorption and reduction process was further explored at the molecular and electronic levels by density functional theory (DFT) and front orbital theory (FOT) simulations. The analysis of DFT and FOT indicated that the synergistic effect between S and N functional groups was exhibited during the Cr(VI) removal process. Considering the existence of synergistic effects between N and S functional groups during adsorption, the S and N content and form were modified collaboratively. Increasing the relative content of pyrrolic N may be the most effective pathway for improving removal performance. Besides that, S5C5-AC exhibited excellent adsorption capacity over a high coexisting ion concentration range and various actual water bodies and regeneration performance, which indicated that S5C5-AC had promising potential for the remediation of wastewater in industrial applications.

Fabrication of activated carbon from Acacia Crassicarpa bark by carbothermal functionalization for adsorptive removal the dyes in aqueous solution

Activated carbon adsorbent prepared from Acacia Crassicarpa bark has been successfully synthesized via carbonization and chemical activation processes to investigate the elimination of hazardous dyes in industrial wastewater, specifically the anionic dye methyl orange (MO) and the cationic dye methylene blue (MB) in this study. The Acacia Crassicarpa bark was washed with distilled water and dried it in an electric oven at 100 °C. The carbonization process was carried out at a temperature of 1050 °C in the Argon atmosphere and thoroughly was activated by NaOH. The results showed that a high BET surface area of 711.05 m2/g was obtained. XRD pattern presented that the high content of crystalline carbon was formed and carbon content was achieved approximately 83%. Also, SEM images illustrated the average size of carbon is 2.58 μm and surface structure of activated carbon appeared the pores inside the particle. The Langmuir was observed to fit the adsorption data well. The maximum equilibrium adsorption capacities predicted by the Langmuir isotherm were found to be 156.25 mg/g and 144.09 mg/g for MO and MB, respectively. All of those results confirm that the activated carbon originated from Acacia Crassicarpa bark can potentially be applied for water purification treatment. In comparison to traditional charcoal, this activated carbon presents numerous advantages. Notably, it can integrate into the biomass energy cycle, improve filtration capabilities, and result in cost savings.

A Hierarchical Porous Aerogel Prepared from Conjugated Polymer for Rapid and Effective Removal of Organic Micro‐Pollutants from Water

AbstractWater pollution caused by organic micro‐pollutants is seriously harmful to aquatic ecosystem and human health. In this work, a hierarchical porous aerogel (HPAG) prepared from rigid conjugated polymers is used to remove organic micro‐pollutants from water. Thanks to the hierarchical porous structure and rich π electrons, HPAG showed a fast adsorption rate and high adsorption capacity for adsorbates. The maximum equilibrium adsorption capacity of HPAG for bisphenol A, 1‐naphthylamine, and naphthalene is 60.5, 50.9 and 63.9 mg g−1 at 10 ppm, respectively, and the adsorption behaviors were in accordance with the Freundlich model. HPAG exhibited a high preference in adsorbing organic micro‐pollutants with high hydrophobicity, and the removal efficiency for polycyclic aromatic hydrocarbons reached over 95%. The HPAG can be easily recycled and regenerated after washing with dichloromethane, and the adsorption performance maintained above 82% after 5 cycles.

In situ polyaniline polymerization on electrospun cellulose acetate nanofibers derived from recycled waste filter butts of cigarettes for the enhanced removal of methyl orange and rhodamine

In this study, waste cigarette butts (CBs) were processed to produce electrospun cellulose acetate (CA) nanofibrous membranes modified with polyaniline (PANI) via chemical oxidation polymerization. This cost-effective method of preparing CA coated with PANI was initially investigated by comparing CA, CA-PANI, and CA-dPANI (as deprotonated PANI) for the rapid adsorption of cationic and anionic dyes. The results depicted CA-PANI with the highest dye removal capacity. As the optimum material, CA-PANI was applied to remove methyl orange (MO) and rhodamine chloride (RC) dye from an aqueous phase. Essential factors: contact time, solution pH, initial dye concentration, nanofiber dosage, and temperature of solution were evaluated with maximum equilibrium adsorption capacity and removal percentage achieved for MO as 24.87 mg/g and 99 %, for RC as 6.93 mg/g and 55 %, respectively. The adsorptive experimental data for both dyes best fitted the pseudo-second-order kinetic, intraparticle diffusion, and Freundlich models. Moreover, the thermodynamics result indicated the adsorption processes were exothermic and spontaneous in nature. Reusability studies also showed the stable performance of CA-PANI material for up to 7 adsorption-desorption cycles. The high dye removal efficiency suggests that the adsorbent material in the water filtration of azo dyes.

Hydrophilic porous boronate imprinted hydrogels for ultrafast transport and highly specific separation of flavoniods: A interfacial cooperative emulsion imprinted strategy based on microreactors

Hydrogel-based imprinted materials with specific-recognition and ultrafast transport have been considered as one of the most promising sorbents in the selective separation fields. Nonetheless, the traditional hydrogel imprinted sorbents still facing the low-level interfacial consistency between substrate polymer and imprinted sites, unordered arrangement and easy agglomeration of recognizing sites on hydrogel matrix, causing poor selectivity of specific molecular transport. For the first time, the one-step RAFT Pickering HIPEs emulsion imprinted methods were designed to fabricate porous hydrophilic boronate affinity imprinted hydrogels (POH-BA-MIPs) for the specific separation and purification of Naringin (NRG). As expected, the novel RAFT solid emulsifier can not only enhance the emulsion stability and mechanical performance of the hydrogel, but also introduce the self-initiating function. Benefiting from the hydrogel’s porous structure and the highly accessible and uniform imprinted sites via Pickering emulsion template, the POH-BA-MIPs exhibited strong binding affinity and selectivity to the targeted molecules. The maximum equilibrium adsorption capacity of POH-BA-MIPs were 53.27 µmol g−1 at 308 K within 360 min. The kinetic nonlinear pseudo-second-order model (R2 = 0.997) can well explain the adsorption kinetic than pseudo-first-order model (R2 = 0.986), indicating that chemisorption is mainly the rate-limiting step. Besides, the adsorption amounts of POH-BA-MIPs were 3.74 times higher than that of non-imprinted adsorbents (POH-BA-NIPs). After six consecutive adsorption–desorption cycles, the obtained POH-BA-MIPs demonstrated considerable reusability, retaining 91.28 % of the initial adsorption capacity. Meanwhile, the coarse NRG products can be effectively purified to 93.16 %. The obtained purified NRG had better antibacterial performance against Staphylococcus aureus. This work provides a novel strategy for constructing porous boronate affinity imprinted hydrogels for specific capture of targeted flavonoid molecules, which exhibited broad practical application potential.

A versatile MOF liquids-based Janus fibrous membrane towards complex oil/water separation and heavy metal ions removal

As an emerging material, porous liquids (PLs) have attracted wide attention and are applied in oily wastewater for the effective elimination of heavy metal ions due to their permanent pore structure, mobility, and superhydrophilicity. However, it remains a challenge to further enhance the separation performance of PLs. Here, a novel metal–organic framework (MOF) porous liquid was synthesized and mixed with a polyacrylonitrile (PAN) solution to produce an asymmetrical Janus fibrous membrane by electrostatic spinning technique. Benefiting from the synergistic effect of the electric field and self-migrating properties of MOF PLs, the Janus membranes exhibited ultrahigh flux of 25310.26 L m-2h−1 bar−1, outstanding separation efficiency (reaching up to 99.99 %) in various oil–water emulsions and high antimicrobial activity (>99.9 %). More impressively, the obtained Janus membranes maintained long-term stability, with separation efficiencies consistently as high as 99.5 %. Meanwhile, the porous structure of MOF PLs with abundant active sites and affinity of polyethylene glycol (PEG) flexible chain for metal ions facilitates the adsorption of metal ions with a maximum equilibrium adsorption capacity of 205 mg/g, which is superior to other literature reported. These results demonstrated that the versatile MOF PLs-based Janus fibrous membranes had a promising application prospect in addressing the challenges associated with such wastewater treatment.

In-depth descriptive investigation of composite sorbent based self-assembled magnetic halloysite nanotube-graphene oxide: Actual use case study for rutin

In this study, a three-dimensional nanocomposite with magnetic features made of magnetic iron oxide nanoparticles (Fe3O4), graphene oxide (GO) and halloysite nanotube (Hal) was prepared and introduced for rutin separation from real sample based on magnetic solid phase extraction (MSPE) process. Hal was modified with chitosan (Hal-COS) and showed positive charge, which can combine with GO by electrostatic force self-assembly to fabricate Hal-GO. Based on this, in-situ growth of magnetic sphere on the surface of Hal-GO demonstrated high specific surface area, chemical and thermal stability, water solubility, and capacity of easy separation in aqueous solution. Several characterizations including FT-IR, HRTEM, TGA and XRD evidenced the successful synthesis of the nanocomposite. The results showed that the optimum adsorption pH was 6 and the optimum adsorption temperature was 25 °C. In addition, further experiments showed that the adsorption process conformed to the Langmuir adsorption model and pseudo-second-order kinetic model, which indicated that the maximum equilibrium adsorption capacity was 107.8 mg g−1 and the maximum equilibrium adsorption time was 120 min. With the optimized conditions, the methodological validation experiments showed that the linear range of MSPE based on Fe3O4@(Hal-GO) combined with HPLC was 10–100 μg mL−1, the correlation coefficient of the fitting equation was 0.9991, the LOD and LOQ reached 0.87 μg mL−1 and 2.9 μg mL−1 respectively. It was confirmed that prepared Fe3O4@(Hal-GO) supported efficient enrichment of rutin when the results were compared to those of other studies.

Adsorption performance on tetracycline by novel magnetic adsorbent derived from hydrochar of low-rank coal and sewage sludge

Herein, a novel magnetic tetracycline (TC) adsorbent (S3C7-Fe) was prepared by co-hydrothermal carbonization (HTC) of sewage sludge (SS) and low-rank coal (LC) combining with K2FeO4 modification. The adsorption performance at different conditions, adsorption kinetics, isotherms and thermodynamics were investigated. The results showed that S3C7-Fe exhibited high TC removal efficiency over a wide pH range (2∼11) and a high coexisting ion concentration range (50∼200 mg/L), and the maximum equilibrium adsorption capacity could reach to 884.04 mg/g. TC adsorption process by S3C7-Fe fitted the Langmuir and pseudo-second-order models, and the adsorption process was homogeneous and dominated by chemisorption. The π-π EDA interaction between the S3C7-Fe and TC molecular was the main mechanism, and pore filling, hydrogen bonding and cation-π complexation also contributed to the adsorption. Besides that, the microscopic interface interaction mechanism between the adsorbent and TC was analyzed both at molecular and electronic levels through theoretical calculations by density functional theory and frontier orbital theory. Interestingly, the results indicated that the oxygen and nitrogen containing functional groups in the adsorbent surface facilitated TC adsorption, and increasing the relative content of COOH and pyrrolic N could be the most effective pathway for improving adsorption capacity.

Iodine and Nickel Ions Adsorption by Conjugated Copolymers Bearing Repeating Units of Dicyclopentapyrenyl and Various Thiophene Derivatives.

The synthesis of three conjugated copolymers TPP1-3 was carried out using a palladium-catalyzed [3+2] cycloaddition polymerization of 1,6-dibromopyrene with various dialkynyl thiophene derivatives 3a-c. The target copolymers were obtained in excellent yields and high purity, as confirmed by instrumental analyses. TPP1-3 were found to divulge a conspicuous iodine adsorption capacity up to 3900 mg g-1, whereas the adsorption mechanism studies revealed a pseudo-second-order kinetic model. Furthermore, recyclability tests of TPP3, the copolymer which revealed the maximum iodine uptake, disclosed its efficient regeneration even after numerous adsorption-desorption cycles. Interestingly, the target copolymers proved promising nickel ions capture efficiencies from water with a maximum equilibrium adsorption capacity (qe) of 48.5 mg g-1.

Graphene oxide nanosheets immobilised on honeycomb pore structure of pomelo peel for enhanced removal of methylene blue.

Herein, for the first time, a simple, green, direct immersion immobilisation method is reported for graphene oxide (GO) nanosheets using pomelo peel (PL) as a substrate. A GO/PL porous sponge was successfully prepared and used to remove methylene blue (MB) from dye wastewater. Considering the porosity, hydrophilicity and elasticity of the PL, the PL was placed in a GO aqueous suspension through direct immersion immobilisation. The carboxyl and hydroxyl groups in the peel could effectively capture and immobilise the GO nanosheets. GO was adsorbed into the PL pores and dispersed throughout the PL. Finally, the prepared super-hydrophilic and elastic GO/PL exhibited excellent adsorption performance towards MB in dye wastewater. The adsorption results revealed that the adsorption behaviour was consistent with the Langmuir isotherm and quasi-secondary kinetic models. The maximum equilibrium adsorption capacity of GO/PL towards MB was 124.2mg/g, exceeding the values obtained for most of the previously reported adsorbents. Moreover, after five consecutive adsorption-desorption cycles, GO/PL retained 75% of its initial adsorption capacity. Mechanistic analysis revealed that pore filling, electrostatic attraction, ion exchange and hydrogen bonding interactions are the primary driving forces facilitating MB adsorption.