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The operation of the Cansolv tail gas treatment device in natural gas plants generates acidic and alkaline wastewater from the venturi unit and amine purification unit (APU), respectively. The APU wastewater is complex in composition and contains hard-to-degrade organic matter, which can adversely impact the normal functioning of the water treatment system. This study assesses the efficacy of three ozone-based advanced oxidation processes (ozone (O 3 ), ozone/hydrogen peroxide (O 3 /H 2 O 2 ), and ozone/Fenton (O 3 /Fenton)) for treating Cansolv wastewater, with chemical oxygen demand (COD) and total organic carbon (TOC) serving as indicators of organic degradation. The findings demonstrate that all three processes effectively eliminate coloration and reducible sulfur, with O 3 /Fenton exhibiting superior performance in removing organic substances. The treated wastewater has a clarified light-yellow appearance with residual COD levels at 43 mg L -1 . Under the optimum Fenton oxidation conditions (initial pH 5, H 2 O 2 dosage 97.8 mmol L -1 , FeSO 4 ·7H 2 O dosage 550 mg L -1 ), average TOC and COD removal rates reached 50% and 97%, respectively. After a treatment duration of 60 minutes, the wastewater demonstrated an enhanced membrane-specific flux, confirming the effectiveness of the O 3 /Fenton oxidation process in mitigating membrane fouling while ensuring the stable operation of the wastewater treatment system., Competing Interests: There are no known competing financial interests or personal relationships that could affect the work reported in this article., (This journal is © The Royal Society of Chemistry.)

Despite extensive efforts, only three main strategies have been developed to synthesize covalent triazine-based frameworks (CTFs) thus far. We report herein a totally new synthetic strategy which allows C-C bonds in the CTFs to be formed through aromatic nucleophilic substitution reactions. The as-synthesized CTF-1 and CTF-2 exhibited photocatalytic water splitting activity comparable to the CTFs made using ionothermal or Brønsted acid-catalyzed polymerization. Interestingly, CTF-2 distinguished itself by its two-photon fluorescence (emission at ∼530 nm under irradiation at either 400 nm or 800 nm)., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Direct electrosynthesis of hydrogen peroxide (H2O2) by oxygen reduction is a green and safe strategy to replace the traditional anthraquinone process. Herein, we have designed a two-dimensional redox-active cationic covalent triazine network to be used directly as a cost-effective metal-free electrocatalyst for the oxygen reduction reaction (ORR) to form H2O2. Such a dicationic 2D polymer possesses a porous structure with pore diameters of 2-10 nm and a total N content of 13.3 wt%. The electron paramagnetic resonance experiment confirms the reduction of a viologen-based polymer to radical cations and the subsequent generation of superoxygen radicals. The radical characteristics and high N content within this polymer are the essential for the efficient ORR via a two-electron pathway. As a result, the present electrocatalyst exhibits a high ORR activity and excellent H2O2 selectivity (∼85%), thus providing a feasible possibility of designing highly selective metal-free electrocatalysts for electrocatalytic production of H2O2 from O2.

Installation of m-benzoic acid functionalities on pillar[5]arene rims resulted in bis- and mono(m-benzoic acid)-functionalized pillar[5]arenes 1 and 2. Bis(m-benzoic acid)-functionalized pillar[5]arene 1 was able to self-assemble to form one-dimensional channels with DMF molecules residing in pillar[5]arene cavities. Esterification of two carboxylic acids in 1 with decane-1,10-diol did not afford a [1]catenane, but a bicyclic compound. Although 1-decanol esterification of mono(m-benzoic acid)-functionalized pillar[5]arene 2 did not form a self-included [1]pseudorotaxane-like structure, a mono(decyl m-benzoate)-functionalized pillar[5]arene bearing an ethyl acetate chain was found to form a self-included complex with the ethyl acetate moiety residing inside the pillar[5]arene cavity.

Multicavity macrocyclic hosts are host molecules comprising more than one macrocyclic guest binding components connected through multipoint linkages. Macrocycles, such as crown ethers, pillar[n]arenes, calix[n]arenes, and calix[4]pyrroles, have been used to fabricate multicavity hosts, either homotopic or heterotopic. This review is mainly focused on the molecular structures and host-guest behaviors of multicavity macrocyclic host molecules and their applications in the assembly of sophisticated supramolecular architectures.

A topologically novel [2]rota[2]catenane containing both a pillar[5]arene-imidazolium based [2]rotaxane subunit and a crown ether-tetracationic cyclophane based [2]catenane one was designed and constructed. The structure of the [2]rota[2]catenane was thoroughly characterized by NMR spectra, MS spectrometry and single crystal X-ray diffraction analysis.

A bicyclic host molecule 1 consisting of a pillar[5]arene and a 1,5-dioxynaphthalene-based crown ether unit has been synthesized, and the two cyclic subunits in 1 were found to recognize two different guest molecules (1,4-dicyanobutane and paraquat) selectively or take up the two guest molecules simultaneously.