Bifunctional nanozyme of copper organophyllosilicate for the ultrasensitive detection of hydroquinone.

The rapid development of nanozymes for ultrasensitive detection of contaminate has resulted in considerable attention. Herein, a carboxyl- and aminopropyl-functionalized copper organophyllosilicate (Cu-CAP) was synthesized by a facile, one-pot sol-gel method. The bifunctional groups endow it with superior catalytic activity than that of natural enzyme. Besides, it possesses outstanding catalytic stability under harsh conditions such as high temperature, extremely high or low pH, and high salinity. Apart from laccase-mimetic activity, Cu-CAP also shows oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) to the blue-colored TMBox in the presence of H2O2, which is similar to natural horseradish peroxidase (HRP). Interestingly, this colorimetric system was suppressed by hydroquinone (HQ) specifically. Inspired by this, Cu-CAP was used to develop a highly sensitive and selective colorimetric method for the determination of HQ. This assay displayed an extremely low detection limit of 23 nM and was applied for the detection of HQ in environmental water with high accuracy. This approach offers a new route for the rational design of high performance nanozymes for environmental and biosensing applications.

The analcime-bearing rock immobilized microalgae: Stress resistance, psychrotolerance, phenol removal.

The development of synergetic biogeocomplices for biodegradation of recalcitrant organic pollutants is an urgently needed to achieve the environmental sustainability. The biogeosorbent based on the analcime-bearing rock immobilized Chlorella vulgaris f. globosa was developed to remove phenol from polluted waterbodies. The microalgae biofilm formation on the ABR resulted in 1.6 × 104 cells/mm2. Stress testing showed that low temperatures up to -30 °C did not adversely affect the cell viability, the dehydrogenase activity of the biogeosorbent exposed was 5.1 mg of formazan/mL. Under phenol-stress conditions, aggregation of suspended cells was observed. The biogeosorbent was more stress resistant than the microalgal suspension, and also reduced the time of exposure and had no secondary waste in comparison with the ABR. After having been treated, phenol removal was found to increase from 70 to 72% for MA, from 27 to 93% for ABR, from 82 to 93% for the biogeosorbent.