Remediation of wastewater with solid waste-based adsorbents is of great environmental significance, but most current waste-based adsorbents suffer from low efficiency. In this work, aminated waste paper (WP-NH 2 ) membrane is successfully prepared by oxidation of various types of waste paper followed by grafting and crosslinking polyethyleneimine (PEI). WP-NH 2 shows extremely high adsorption for various anionic dyes and antibiotics. Specifically, the adsorption amount for methyl orange (MO) and tetracycline (Tc) are 2156.2 mg·g −1 and 253.7 mg·g −1 , respectively. WP-NH 2 is stable enough to be regenerated several times and still maintains high adsorption efficiency. Mechanistic studies show that the adsorption toward anionic MO is mainly through electrostatic interaction and hydrogen bonding, and the adsorption of antibiotic Tc relies on hydrogen bonding and Lewis acid-base reaction. Grafting PEI on the fiber surface enables efficient exposure of adsorption sites. Therefore, WP-NH 2 membrane can quickly, continuously and efficiently filter out MO and Tc from water. After 5800 L·m −2 MO and 3150 L·m −2 Tc filtration, the interception rate of the two contaminants is still higher than 90 %. Moreover, WP-NH 2 shows high selectivity and can be used for efficient separation of dye mixture. These results reveal that this advanced adsorbent made from waste paper has great potential application in industrial dye and antibiotic wastewater remediation.
Pharmaceuticals in hospital effluents, often discharged into the public sewage network without sufficient treatment, have shown negative impacts to the human health and aquatic environment. However, the conventional adsorbents used to remove these micropollutants had several deficiencies, including slow uptake kinetics and poor selectivity . To overcome these challenges, water-compatible Janus MIP particles (J-MIPs) with mouth-like openings were synthesized using seeded interfacial polymerization in this work. Among the series of J-MIPs, the selected J-MIP 3 showed fast binding kinetics (∼40 s) towards the target pollutant. The theoretical and instrumental analysis suggested that the electrostatic interaction, hydrogen bond and hydrophobic reaction constituted the dominant mechanism for J-MIP 3 's recognition of target pharmaceutical. Selectivity and robustness tests indicated that the synthetic method was promising in practical application. Finally, the feasibility of the J-MIP 3 fixed-bed column in the rapid removal of propranolol (PRO) from hospital effluents was successfully demonstrated. Compared to the activated carbon fixed-bed column, the J-MIP 3 fixed-bed column showed at least 7-fold enhancement in its treatment efficiency. To the best of our knowledge, this is the first time that the accelerated mass transfer and fast removal of the pharmaceutical from wastewater have been achieved by the synthetic receptor with asymmetric structure. We believe the present study will open new avenues for the development of multi-functional molecularly imprinted polymers as well as Janus materials in environmental science.
Practical biological and environmental samples always contain both acidic and basic substances, and the samples are always precious. Thus, separation of analytes with different nature from the same sample was of great significance. Successive liquid phase microextraction (sLPME) of acidic and basic analytes under optimal extraction conditions was therefore proposed for the first time. The concept of sLPME was proved by using three acidic analytes (naproxen, flurbiprofen and diclofenac) and three basic analytes (haloperidol, fluoxetine and sertraline) as model analytes, and using polypropylene glycol with an average molecular weight of 4000 (PPG4000) as SLM . The recoveries of all target analytes by sLPME were similar to that by individual LPME due to good affinity of PPG4000 to both acidic and basic analytes. Under optimal extraction conditions, the recoveries for all analytes by sLPME from urine samples were in the range of 62%–95%. Moreover, combined with LC-MS/MS, such sLPME approach was also evaluated with urine samples. The matrix effect of sLPME-LC-MS/MS at different levels for all analytes ranged from −14.1%–13.2%. The linear ranges with R 2 > 0.996 were 5–1000 ng mL −1 for basic analytes, and 20–1000 ng mL −1 for acidic analytes except diclofenac (1–1000 ng mL −1 ). The repeatability and accuracy at four levels were in the range of 3%–10% and 86%–120%, respectively. The limit of detection (LOD, S/N = 3) and limit of quantification (LOQ, S/N = 10) were found to be 0.07–0.49 ng mL −1 and 0.25–1.63 ng mL −1 , respectively. Finally, the strategy for constructing a sLPME system was further confirmed with urine, plasma and saliva using another two versatile SLM solvents possessing high affinity to both acidic and basic analytes. Successive LPME enabled separation of acidic and basic analytes from the same sample under optimum extraction conditions for all target analytes. Thus, we believe that the sLPME system will become a potent platform for forensic toxicology analysis, food science, environmental analysis and epidemiology study.
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