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Conjugated polymers are promising catalysts for photocatalytic hydrogen evolution (PHE) from water. Here, a series of imine-linked conjugated polymers were synthesized via Schiff-base condensation using an easy and low-temperature protocol with cheap raw materials and green solvent. Several readily available diaminobenzene with different amino substitution positions on the phenyl ring were used to react with terephthalaldehyde, leading to formation of polymers varying from one dimensional (1D) nanorods to two dimensional (2D) and three-dimensional (3D) networks. The obtained polymer with 1D crystalline structure was found to show the highest hydrogen production rate at ~24.3 μmol/h under visible light irradiation (λ > 420 nm) without adding any additional metal co-catalysts. Detailed analysis of the structure, morphology and photoelectron-chemical properties of these as-synthesized polymers leads to the conclusion that 1D nanorods and high LUMO (the lowest unoccupied molecular orbital) play more important roles than large conjugation and surface area in improving the PHE capacity of polymer. This study illustrated a protocol for the production of metal-free photocatalyst synthesized using cheap and green solvent at low-temperature.

Fluoride removal is an urgent problem in the field of water treatment. In this study, fluoride adsorption was performed using Ca-Modified Mg-Zr Mixed Metal Oxides (CCMZ), which was successfully prepared by a green hydrothermal process followed by high-temperature calcination. CCMZ was prepared using a lamellar MgO and ZrO2 Mixed Metal Oxide (MMO). Then, calcium (Ca, a strong fluorophilic metal) was dispersed over the MMO, to form a 3D spongy structure. The obtained microstructural features significantly enhanced the fluoride migration and diffusion, resulting in an adsorption capacity of 144.05 mg/g. The agglomeration of the products was effectively avoided, so CCMZ showed good selectivity and reusability. Batch adsorption experiments and subsequent sample characterization showed that the fluoride adsorption mechanism of CCMZ involved electrostatic attraction and ion exchange mechanism. Therefore, this manuscript provides a rational design and a simple preparation method for a new class of fluoride adsorbents.

In this study, we used a combined vacuum-ultraviolet (VUV) and O3 process treating the chemical precipitation pre-treated incineration leachate membrane concentrate to further decompose substantial refractory organics which led to membrane organic fouling in the subsequent membrane distillation process. The highest removal of COD (88.1%) was achieved when 50 mg/min of O3 dosage was used at a pH of 11.5–12. Multi-spectrum methods, molecular weight distribution (MW), gas chromatography-mass spectrometry (GC–MS), two-dimensional correlation spectroscopy (2D-COS), and hetero-spectral 2D-COS were used to investigate the organics degradation mechanism. The combined action of O3 and hydroxyl radicals (•OH) effectively degraded macromolecular organics with high aromaticity and high conjugation (mainly distributed at 1–3 kDa) into aliphatic products with lower molecular weight ( fulvic-like acids > protein-like substances. Organic acids (acetate, propionate, and butyrate) also accumulated in the VUV/O3 systems.

Photocatalysis is an effective and environmentally-friendly technique for antibiotics degradation in wastewater. Herein, a novel rationally designed HexaAcetyl-Reductive Cercosporin/Hydroxyapatite (HARCP/HAp) composite was simply fabricated through a convenient bench-top fabrication method for the efficient, fast and complete removal of tetracycline (TC) within 10 min upon 32 W compact fluorescent lamp (CFL) irradiation. The photoactivity of the fabricated HARCP/HAp-2 (0.5719 min−1) to remove TC showed dramatic enhancement compared with HARCP (0.0098 min−1) or HAp (0.0374 min−1). More importantly, a broad range concentration (30–70 mg L−1) of 50 mL TC solutions, even a scalable 5 L solution at the real situation of 158 μg L−1 under natural sunlight, could be photoremoved efficiently by this new photocatalytic system. Meanwhile, it exhibited excellent stability and reusability for repeated usage. The photoremoval process mechanically involved superoxide radical anion (•O2−), hydroxyl radical (•OH) and hole (h+). Therefore, we provided a novel fabrication of the organic-containing photocatalyst composite involving the natural product-derived HARCP for the efficient removal of TC, avoiding the expensive and polluting heavy metals, harsh conditions to fabricate and high-power light sources.

Exploring catalytic processes performed under natural conditions is interesting, but there remains a great challenge in developing highly efficient catalysts for natural oxidation of alcohols. Herein, we report a chloroplast-like catalyst comprised of photoactive carbon dots (CDs), catalytically active Pt nanoparticles, and amphiphilic nanotubes. Under simulated and real natural reaction conditions, our catalysts exhibited remarkable activity and long-term reusability for the oxidation of various alcohols, significantly outperforming that of other counterpart catalysts and reported thermal/photocatalytic systems. It was demonstrated that when the carbon dots and the amphiphilic nanotubes respectively played a role in the light-harvesting and the substrate transport the Pt/CDs heterointerface acted as the active center for the matter conversion. Such an elaborate cooperation, an advanced process in the photosynthesis of plant, contributed to the excellent catalytic performance. This contribution provides a new design concept for artificial photocatalysts, which is very promising for developing sustainable catalytic processes.