The regeneration of WPAC through pyrolysis and its adsorption capacity of phosphorus were studied. The optimum conditions for WPAC regeneration were 650 °C and 2 h which resulted in a recovery of BET surface and total pore volume with a value of 1161.4 m2/g and 1.2176 m3/g. WPAC had a maximum PO43−-P adsorption capacity of 9.65 mg/g which was 48.93% of PAC, while RWPAC had a maximum PO43−-P adsorption capacity of 15.31 mg/g which was 77.64% of PAC. The kinetic analysis revealed that Langmuir model could well describe the adsorption process of PAC, WPAC and RWPAC on PO43−-P and the PO43−-P adsorption followed the pseudo-second-order model.

Recently, several significant progresses have been made on the studies of extracellular and intracellular ice formation based on high-speed camera and cryomicroscope. This experimental methodology could accurately capture the rapid formation process of ice crystals at microscale. However, quantitative interpretation on such phase change behavior still reserved a tough issue. Here, in this paper, we quantitatively studied the ice crystals growth in three kinds of cryoprotectants like dimethyl sulfoxide (DMSO), sucrose, and trehalose via high-speed camera, cryomicroscope as well as the proposed data processing method. Several critical impact factors such as the concentration of cryoprotectants and the cooling rate have been investigated. Particularly, an efficient image processing technology has been developed to quantify the growth rate and morphology of the ice crystals. The results indicate that the species and concentration of cryoprotectants and the cooling rate could significantly affect the growth rate and morphology of ice crystals. DMSO is better than trehalose and sucrose as cryoprotectant because of the molecular structure. This work established a new methodology to quantify the ice crystals growth and would enhance current understanding of the factors for ice crystals formation. It is also expected to help optimize the cryopreservation process in the near future.

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