Aqueous adsorption of bisphenol A over a porphyrinic porous organic polymer

Construction of magnetic azo-linked porous polymer for highly-efficient enrichment and separation of phenolic endocrine disruptors from environmental water and fish

Developing effective methods for highly sensitive detection of phenolic endocrine disruptors (EDCs) is especially urgent. Herein, a magnetic hydroxyl-functional porous organic polymer (M-FH-POP) was facilely synthesized by green diazo-couple reaction using basic fuchsin and hesperetin as monomer for the first time. M-FH-POP delivered superior adsorption performance for phenolic EDCs. The adsorption mechanism was hydrogen bonds, hydrophobic interaction and π-π interplay. With M-FH-POP as adsorbent, a magnetic solid phase extraction method was established for extracting trace phenolic EDCs (bisphenol A, 4-tert-butylphenol, bisphenol F and bisphenol B) in water and fish before ultra-high performance liquid chromatography tandem mass spectrometry analysis. The method displayed low detection limit (S/N = 3) of 0.05-0.15 ng mL-1 for water and 0.08-0.3 ng g-1 for fish. The spiked recoveries were 88.3 %-109.8 % with the relative standard deviations of 2.4 %-6.4 %. The method offers a new strategy for sensitive determination of phenolic EDCs in water and fish samples.

Green synthesis of magnetic azo-linked porous organic polymers with recyclable properties for enhanced Bisphenol-A adsorption from aqueous solutions

Porous organic polymers (POPs) present superior adsorption performance to steroid endocrine disruptors. However, the effective recovery and high cost have been a big limitation for their large-scale applications. Herein, magnetic azo-linked porous polymers (Fe3O4@SiO2/ALP-p) were designed and prepared in a green synthesis approach using low-price materials from phloroglucinol and pararosaniline via a diazo-coupling reaction under standard temperature and pressure conditions, which embedded with Fe3O4@SiO2 nanoparticles to form three-dimensional interlayer network structure with flexible-rigid interweaving. The saturated adsorption capacity to bisphenol-A (BPA) was 485.09 mg/g at 298 K, which increased by 1.4 times compared with ALP-p of relatively smaller mass density. This enhanced adsorption was ascribed to increment from surface adsorption and pore filling with 2.3 times of specific surface area and 2.6 times of pore volume, although the total organic functional groups decreased with Fe3O4@SiO2 amendment. Also, the adsorption rate increased by about 1.1 and 1.5-fold due to enhancement in the initial stage of surface adsorption and subsequent stage pore diffusion, respectively. Moreover, this adsorbent could be used in broad pH (3.0-7.0) and salinity adaptability (<0.5 mol/L). The loss of adsorption capacity and magnetic recovery were lower than 1.1% and 0.8% in each operation cycle because of the flexible-rigid interweave. This excellent performance was contributed by synergistic effects from physisorption and chemisorption, such as pore filling, electrostatic attraction, π-π stacking, hydrogen bonding, and hydrophobic interaction. This study offered a cost-effective, high-performing, and ecologically friendly material along with a green preparation method.

Green construction of magnetic azo porous organic polymer for highly efficient enrichment and detection of phenolic endocrine disruptors

Porous organic polymers (POPs) are prominent sorbents for effective extraction of endocrine disrupting chemicals (EDCs). However, green and sustainable construction of functional POPs is still challenging. Herein, we developed a magnetic azo POP (Mazo-POP) for the first time using hydroxy-rich natural kaempferol and low-toxic basic fuchsin as monomers through a diazo coupling reaction. The Mazo-POP exhibited excellent extraction capabilities for EDCs with a phenolic structure. Consequently, it was used as a magnetic sorbent for extracting phenolic EDCs from water and fish samples, followed by ultrahigh-performance liquid chromatography-tandem mass spectrometric detection. The Mazo-POP based analytical method afforded a good linearity of 0.06-100 ng mL-1 and 0.3-500 ng g-1 for water and fish samples respectively, with detection limits (S/N = 3) of 0.02-0.5 ng mL-1 and 0.1-1.5 ng g-1, respectively. The method recovery was from 85.2% to 109% and relative standard deviation was less 5.3%. Moreover, the effective adsorption was mainly contributed by hydrogen bond, π-π interaction, pore filling and hydrophobic interaction. This work not only provides an efficient method for sensitive determination of phenolic EDCs, but also highlights the significance of green preparation of environmentally friendly sorbents for enriching/adsorbing pollutants.

Porphyrin-Based Conjugated Microporous Polymer Loaded with Nanoscale Zerovalent Iron for the Degradation of Organic Pollutants under Visible Light

The degradation of organic dye from waterbodies is of great significance for clean production and environmental remediation. Herein, two porphyrin-based conjugated microporous polymers (CMPs) loaded with nanoscale zerovalent iron (named as Por-CMPs-1-2@nZVI) were successfully fabricated by Sonogashira-Hagihara coupling reactions and the liquid-phase method. The as-synthesized Por-CMPs-1-2@nZVI composites were characterized by various means of analysis, and it was confirmed that Por-CMPs-1-2 loaded with nZVI had good photocatalytic performance. Calculated by ultraviolet-visible spectrum, the band-gap energies of Por-CMPs-1@nZVI and Por-CMPs-2@nZVI were 1.45 and 1.32 eV, respectively, indicating that both can be activated by visible light. The photodegradation of organic dye experiments demonstrated that Por-CMPs-2@nZVI degraded 98.0% of 10 ppm Methylene Blue (MB) within 150 min, which is higher than that of Por-CMPs-1-2 and Por-CMPs-1@nZVI. The experiment of active substance capture and mechanism of ESR confirmed that superoxide anion and hydroxyl radical were the primary valid substances in the photodegradation process of MB. In addition, the preparation of membrane materials was shown to be a successful strategy to realize engineered scale-up production.

Adsorption and photocatalytic applications of porphyrin-based materials for environmental separation processes: A review

As society progresses and industrializes, the issue of water pollution, caused by a wide array of organic and inorganic pollutants, poses significant risks to both human well-being and the environment. Given its distinctive characteristics, water pollution has become a paramount concern for society, necessitating immediate attention. Numerous studies have been conducted on wastewater treatment, primarily focusing on two key approaches: adsorption and photocatalytic degradation. Adsorption offers unparalleled advantages, including its simplicity, high removal efficiency, and cost-effectiveness. Conversely, photocatalysis harnesses abundant, clean, and non-polluting sunlight, addressing the critical issue of energy scarcity. Porphyrins, which are macrocyclic tetrapyrrole derivatives found widely in nature, have attracted growing interest in recent years. These lipophilic pigments exhibit remarkable chemical stability and have retained their major structural features for up to 1.1 billion years. As such, they are considered vital indicators of life and have been extensively studied, from the remnants of extinct organisms to gain insights into the principles of evolution. Porphyrins are often associated with a central metal ion within their ring system and can be modified through various substituents, including additional rings or ring opening, resulting in a wide range of functionalities. This comprehensive review summarizes recent advancements in the field of porphyrins. It begins by introducing the structures and preparation methods of porphyrins. Subsequently, it delves into notable applications of porphyrins in the context of pollutant adsorption in water and their environmentally friendly photocatalytic degradation.

Covalent organic frameworks: Pioneering remediation solutions for organic pollutants

Covalent Organic Frameworks (COFs) have emerged as a promising class of crystalline porous materials with customizable structures, high surface areas, and tunable functionalities. Their unique properties make them attractive candidates for addressing environmental contamination caused by pharmaceuticals, pesticides, industrial chemicals, persistent organic pollutants (POPs), and endocrine disruptors (EDCs). This review article provides a comprehensive overview of recent advancements and applications of COFs in removing and remedying various environmental contaminants. We delve into the synthesis, properties, and performance of COFs and their potential limitations and future prospects.

Porphyrin/phthalocyanine-based porous organic polymers for pollutant removal and detection: Synthesis, mechanisms, and challenges

The growing global concern about environmental threats due to environmental pollution requires the development of environmentally friendly and efficient removal/detection materials and methods. Porphyrin/phthalocyanine (Por/Pc) based porous organic polymers (POPs) as a newly emerging porous material are prepared through polymerizing building blocks with different structures. Benefiting from the high porosity, adjustable pore structure, and enzyme-like activities, the Por/Pc-POPs can be the ideal platform to study the removal and detection of pollutants. However, a systematic summary of their application in environmental treatment is still lacking to date. In this review, the development of various Por/Pc-POPs for pollutant removal and detection applications over the past decade was systematically addressed for the first time to offer valuable guidance on environmental remediation through the utilization of Por/Pc-POPs. This review is divided into two sections (pollutants removal and detection) focusing on Por/Pc-POPs for organic, inorganic, and gaseous pollutants adsorption, photodegradation, and chemosensing, respectively. The related removal and sensing mechanisms are also discussed, and the methods to improve removal and detection efficiency and selectivity are also summarized. For the future practical application of Por/Pc-POPs, this review provides the emerging research directions and their application possibility and challenges in the removal and detection of pollutants.

Post-cationic modification of a porphyrin-based conjugated microporous polymer for enhanced removal performance of bisphenol A

A porphyrin-based conjugated microporous polymer photocatalyst named LDPO-2 was synthesized by a post-modification approach, which improved its hydrophilicity and visible light absorption ability. LDPO-2 achieved >99.5% removal efficiency for bisphenol A (BPA, 10 ppm) within 12 min of exposure to visible light, and the photocatalytic mechanism and potential degradation pathways were well investigated. LDPO-2 also exhibited impressive removal efficiency against BPA analogues, proving its practical applications in real-water treatment scenarios.

Effective adsorption of bisphenol A from aqueous solution using phosphoric acid-assisted hydrochar

Sycamore leaf biochar (PSAC) was prepared by a two-step phosphoric acid-assisted hydrothermal carbonization combined with a short-time activation method. The characterization results showed that the introduction of phosphoric acid molecules and thermal activation resulted in a substantial increase in the specific surface area (994.21 m2/g) and microporous capacity (0.307 cm3/g) of PSAC. The batch adsorption results showed that the adsorption process of PSAC on bisphenol A (BPA) was best described by the pseudo-second-order kinetic model and Sips isothermal model, with a maximum adsorption capacity of 247.42 mg/g. The adsorption of BPA onto PSAC was determined to be a spontaneous endothermic process. The equilibrium adsorption capacity of PSAC exhibited an upward trend with increasing initial BPA concentration and temperature while decreasing with higher adsorbent dosage and pH value. Coexisting cations and humic acids in water have little impact on the adsorption performance of PSAC for BPA. The adsorption mechanism of BPA by PSAC was mainly governed by pore filling and hydrogen bonding interactions, π-π interactions, and intraparticle diffusion. Furthermore, PSAC demonstrated good reusability by its sustained adsorption capacity of BPA, which remained at 82.6% of the initial adsorption capacity even after four adsorption-desorption cycles. These findings highlight the potential of utilizing low-cost sycamore leaf biochar as an effective adsorbent for the removal of the endocrine disruptor BPA.

Bisphenol A contamination in aquatic environments: a review of sources, environmental concerns, and microbial remediation

The production of polycarbonate, a high-performance transparent plastic, employs bisphenol A, which is a prominent endocrine-disrupting compound. Polycarbonates are frequently used in the manufacturing of food, bottles, storage containers for newborns, and beverage packaging materials. Global production of BPA in 2022 was estimated to be in the region of 10 million tonnes. About 65-70% of all bisphenol A is used to make polycarbonate plastics. Bisphenol A leaches from improperly disposed plastic items and enters the environment through wastewater from plastic-producing industries, contaminating, sediments, surface water, and ground water. The concentration BPA in industrial and domestic wastewater ranges from 16 to 1465 ng/L while in surface water it has been detected 170-3113 ng/L. Wastewater treatment can be highly effective at removing BPA, giving reductions of 91-98%. Regardless, the remaining 2-9% of BPA will continue through to the environment, with low levels of BPA commonly observed in surface water and sediment in the USA and Europe. The health effects of BPA have been the subject of prolonged public and scientific debate, with PubMed listing more than 17,000 scientific papers as of 2023. Bisphenol A poses environmental and health hazards in aquatic systems, affecting ecosystems and human health. While several studies have revealed its presence in aqueous streams, environmentally sound technologies should be explored for its removal from the contaminated environment. Concern is mostly related to its estrogen-like activity, although it can interact with other receptor systems as an endocrine-disrupting chemical. Present review article encompasses the updated information on sources, environmental concerns, and sustainable remediation techniques for bisphenol A removal from aquatic ecosystems, discussing gaps, constraints, and future research requirements.

Efficient recovery of bisphenol A from aqueous solution using K2CO3 activated carbon derived from starch-based polyurethane

Endocrine-disrupting compounds (EDCs) are increasingly polluting water, making it of practical value to develop novel desirable adsorbents for removing these pollutants from wastewater. Here, a simple cross-linking strategy combined with gentle chemical activation was demonstrated to prepare starch polyurethane-activated carbon (STPU-AC) for adsorbing BPA in water. The adsorbents were characterized by various techniques such as FTIR, XPS, Raman, BET, SEM, and zeta potential, and their adsorption properties were investigated comprehensively. Results show that STPU-AC possesses a large surface area (1862.55 m²·g^-1) and an abundance of functional groups, which exhibited superior adsorption capacity for BPA (543.4 mg·g^-1) and favorable regenerative abilities. The adsorption of BPA by STPU-AC follows a pseudo-second-order kinetic model and a Freundlich isotherm model. The effect of aqueous solution chemistry (pH and ionic strength) and the presence of other contaminants (phenol, heavy metals, and dyes) on BPA adsorption was also analyzed. Moreover, theoretical studies further demonstrate that hydroxyl oxygen and pyrrole nitrogen are the primary adsorption sites. We found that the efficient recovery of BPA was associated with pore filling, hydrogen-bonding interaction, hydrophobic effects, and π-π stacking. These findings demonstrate the promising practical application of STPU-AC and provide a basis for the rational design of starch-derived porous carbon.

Macrocycle-Based Porous Organic Polymers for Separation, Sensing, and Catalysis

With the rapid development of materials science, porous organic polymers (POPs) have received remarkable attentions because of their unique properties such as the exceptionally high surface area and flexible molecular design. The ability to incorporate specific functions in a precise manner makes POPs promising platforms for a myriad of applications in molecular adsorption, separation, and catalysis. Therefore, many different types of POPs have been rationally designed and synthesized to expand the scope of advanced materials, endowing them with distinct structures and properties. Recently, supramolecular macrocycles with excellent host-guest complexation abilities are emerging as powerful crosslinkers for developing novel POPs with hierarchical structures and improved performance, which can be well-organized at different spatial scales. Macrocycle-based POPs could have unusual porous, adsorptive, and optical properties when compared to their nonmacrocycle-incorporated counterparts. This cooperation provides valuable insights for the molecular-level understanding of skeletal complexity and diversity. Here, the research advances of macrocycle-based POPs are aptly summarized by showing their syntheses, properties, and applications in terms of separation, sensing, and catalysis. Finally, the current challenging issues in this exciting research field are delineated and a comprehensive outlook is offered for their future directions.

Facile preparation of oxygen-rich porous polymer microspheres from lignin-derived phenols for selective CO2 adsorption and iodine vapor capture

Lignin is a natural O-containing aromatic amorphous polymers from the residues of biorefinery and industrial papermaking, it can derive lots of aromatic phenol chemicals used as industrial raw materials by an efficient depolymerization, and then produce synthetic polymers. Here, we selected six aromatic units from the liquid products of lignin depolymerization, and tried to prepare diversified O-rich hyper-cross-linked polymers (HCPs) by one-pot Friedel-Crafts alkylation reaction for CO₂ and iodine vapor capture. HCP1, HCP2, and HCP3 microspheres possessed similar porous structure with Brunauer-Emmett-Teller (BET) surface areas (S_BET) of 14.1-20.6 m²/g and high O content (26.34-30.68 wt%), while HCP4, HCP5, and HCP6 were composed of many bulks with 3D networks structure, and showed larger S_BET of 15.4-246.9 m²/g and relatively low O content (18.48-26.38 wt%). The results indicated that the chemical position and quantities of substituent groups (methoxy and alkyl) into lignin-derived units had evident impact on their morphology and textural parameters. These HCPs exhibited considerable CO₂ uptake (64.1 mg/g) and selectivity (35.2) at 273 K， and high iodine vapor uptake (192.3 wt%). Moreover, the performance analysis implied that the S_BET and pore volume of these HCPs had not played the dominated roles in the CO₂ and I₂ adsorption, while their pore size distribution, O-functional groups, and electron density will be more important for the capture of the both. This study will offer a facile synthesis of O-rich polymer microsphere adsorbents based on the green and sustainable lignin.

Facile synthesis of porous porphyrin-based polymers by solvent-crosslinking method

Three solvents were employed as crosslinkers to synthesise porous porphyrin-based polymers via Friedel–Crafts alkylation reaction.