Zhongshuai Chang

Hollow imprinted polymer nanorods with a tunable shell using halloysite nanotubes as a sacrificial template for selective recognition and separation of chloramphenicol

The wide use of antibiotics in human therapy and veterinary practice has resulted in the presence of residual antibiotic compounds in water environments, which are harmful to ecology and health. In this work, novel hollow molecularly imprinted nanorods (HMINs) with uniform and controllable thickness of the polymer shell were successfully prepared via a combination of in situ surface precipitation polymerization and halloysite nanotubes sacrificial template method, and were used as an advanced selective nanoadsorbent to remove chloramphenicol (CAP). The physicochemical properties of HMINs were well characterized by FE-SEM, TEM, FT-IR and TG/DTA. HMINs with a shell thickness of 62 nm (HMINs-2) displayed excellent adsorption capacity and fast kinetics. The experimental adsorption equilibrium and kinetic data were best described by the Freundlich isotherm model and the pseudo-second-order rate equation, respectively. Furthermore, HMINs-2 possessed highly specific recognition to CAP in aqueous solutions, as compared with other reference antibiotics. Meanwhile, HMINs-2 also had excellent dispersibility, regeneration properties and thermal stability for the promising potential application in wastewater treatment.

Converting obsolete copy paper to porous carbon materials with preeminent adsorption performance for tetracycline antibiotic

To date, the employment of developed adsorbents in antibiotic wastewater treatment practices is still limited due to their low adsorption capacity, slow kinetics and especially high cost. Thus, in this work, we first report the conversion of obsolete copy paper to highly porous carbon materials (PCMs) via a two-step method: low-temperature carbonization and alkali activation. The influence of activation temperature and KOH content on the porosity and adsorption capacity of PCMs was also studied. Notably, copy paper (CP) is consumed in extremely large quantities with a high proportion being obsoleted; it mainly consists of micro- and nano-cellulose fibers that can be used as an ideal carbon source. The PCMs were characterized by several techniques and methodologies. The PCMs-850-4 exhibited an ultrahigh BET surface area of 3598.95 m2 g−1 and total pore volume of 1.887 cm3 g−1. The influence of temperature, initial concentration, contact time, pH and ionic strength on the adsorption of tetracycline (TC) from water to PCMs-850-4 was investigated through batch adsorption studies. Analyses of adsorption isotherm, kinetics and thermodynamics property were conducted to understand the adsorption behavior. The equilibrium experimental data was well fitted to the Langmuir model, and the kinetic data was best described by the pseudo-second-order rate model. Importantly, the PCMs-850-4 displayed an ultrahigh adsorption of 1437.76 mg g−1 at 298 K, and increasing temperature benefited the adsorption. Also, their fast kinetics and great regeneration make the PCMs-850-4 a promising adsorbent for the low-cost, highly efficient and fast removal of organic pollutants from water environments.

Facile preparation of intercrossed-stacked porous carbon originated from potassium citrate and their highly effective adsorption performance for chloramphenicol

Recently, antibiotics pollution has attracted more interests from many researches which causes potential risks on the ecosystem and human health. Herein, the porous carbons (PCs) was prepared by directly simultaneous carbonization/self-activation of potassium citrate at 750-900°C for chloramphenicol (CAP) removal from aqueous solution. The batch experiments were studied, which indicated that PCs prepared at 850°C, namely PCPCs-850, possessed excellent adsorption ability for CAP with a maximum adsorption amount of 506.1mgg-1. Additionally, PCPCs-850 showed a large BET surface area of 2337.06m2g-1 and microporosity of 89.11% by N2 adsorption-desorption experiment. The Langmuir and pseudo-second-order model could more precisely describe the experimental data. And thermodynamic analysis illustrated that CAP adsorption onto PCPCs-850 was an endothermic and spontaneous process. Importantly, the adsorbent exhibited good stability and regeneration after four times cycles. Based on these excellent performance, it is potential that PCPCs-850 can be used as a promising adsorbent for treating contaminants in wastewater.

Hierarchical porous carbon materials derived from a waste paper towel with ultrafast and ultrahigh performance for adsorption of tetracycline

Herein, waste paper towels, a mass garbage product from daily life, were used as precursors for the production of hierarchical porous carbon (PTHPC) via KOH activation to be used for the removal of tetracycline. In this study, the influence of KOH content on porosity and adsorption capacity was investigated, and the optimal property of hierarchical porous carbon was obtained at weight ratios of carbonization: KOH = 1 : 4 (PTHPC-4). The physico-chemical properties of PTHPC-4 were characterized by different technology. Notably, PTHPC-4 possesses an ultrahigh specific surface area of 3524 m2 g−1 and a large pore volume of 1.839 cm3 g−1. Additionally, the isothermal adsorption results showed that PTHPC-4 displayed an ultrahigh adsorption capacity of 1661.13 mg g−1 for tetracycline, which is superior to other previously reported adsorbents. Moreover, PTHPC-4 also has excellent kinetics performance: when C0 = 100 mg L−1, the pseudo-second-order kinetics constant k2 values at 298, 308 and 318 K are 1.055 × 10−2, 5.731 × 10−2 and 8.916 × 10−2 g mg−1 min−1, respectively, which were 1–3 magnitude higher than previously reported adsorbents. In addition, the investigation of the effect temperature, pH and ionic strength on the adsorption property for tetracycline are included in this study.

Preparation of macroscopic spherical porous carbons@carboxymethylcellulose sodium gel beads and application for removal of tetracycline

The development of practicable and retrievable adsorbents with high adsorption capacity is a technical imperative for water treatment. Herein, we reported a new convenient macroscopic granular adsorbent for the removal of tetracycline (TC) from water by immobilizing porous carbons (PCs) which were obtained via one-step in situ pyrolysis from ethylenediaminetetraacetic acid dipotassium salt dihydrate (EDTA-2K·2H2O) into carboxymethylcellulose sodium (CMCS) gel beads utilising molecular cross-linking. A remarkable similarity can be observed between multivariant gel beads and EDTA-2K·2H2O derived porous carbons (EPCs) according to the characterization results. The adsorption performance was evaluated using batch adsorption studies of TC in aqueous solution: the kinetic results could be fit well by a pseudo-second-order model and intraparticle diffusion was treated as the rate-controlling step; equilibrium adsorption data fitted well to the Langmuir adsorption isotherm yielding a maximum adsorption capacity of 136.9 mg g−1 at 298 K. Importantly, these results indicate that the as-prepared gel beads could be used as facile adsorbents in pharmaceutical wastewater treatment.