Adsorptive removal of tetracycline by sustainable ceramsite substrate from bentonite/red mud/pine sawdust

Abstract

In this study, a novel, sustainable and efficient ceramsite substrate of constructed wetlands (CWs) were prepared for tetracycline (TC) removal by employing bentonite (Ben) and red mud (Rm) as the main materials and pine sawdust (Ps) as the additive. The optimal parameters for Ben/Rm/ ps ceramsite preparation were obtained via orthogonal and one-factor experimental designs, and the optimal parameters were presented as follows: mass ratio of Ben: Rm: Ps = 4:1:0.9, preheating temperature = 240 °C, preheating time = 20 min, calcining temperature = 1150 °C, and calcining time = 14 min. The properties of Ben/Rm/Ps-op ceramsite (obtained at the optimal condition) were first analyzed, including XRD and SEM, and demonstrated a microporous structure with some crystal strength components. Neutral condition and higher temperature were indicated conducive to improve the TC removal efficiency, while coexisting ions (Na + or ca 2+ ) showed adverse effect for TC adsorption by Ben/Rm/Ps-op. In addition, adsorption kinetics and isotherm could be well described by the secondorder kinetics and linear isothermal model, respectively, which suggested chemisorption and multilayer adsorption thickness increased infinitely. The theoretical maximum TC adsorption capacity of Ben/Rm/ Ps-op at 20 °C reached up to 2.5602 mg/g. In addition, Ben/Rm/Ps-op could effectively remove TC as the CWs substrate under a dynamic flow condition. Further, Ben/Rm/Ps-op exhibited high reusability capability and stability for TC removal, and the adsorption amount still remained for 2.13 mg/g (C 0 = 80 mg/L) after three consecutive cycles.As the most widely used spectrum antibiotics, tetracycline (TC) can effectively inhibit the activities of chlamydia, mycoplasma, protozoan parasites, rickettsiae, gram-negative bacteria and gram-positive bacteria 1 . Therefore, it is widely and frequently applied in medical and health, poultry breeding and other industries for disease treatment 2 . Nevertheless, animals usually fail to fully metabolize TC, and most of ingested TC are discharged into the environment, which would pose potent pollution danger to environment consequently 3-6 . Long-term exposure to TC in the environment has caused serious concern about toxicity and bacterial resistance, which leads to ecological damage and threatens human health through bioaccumulation in the food chain 7 . It has been proved that TC can interact with phospholipids and be adsorbed by biological cell membranes, which can also lead to complications of human allergic reactions. Despite of short half-life of TC, the current sewage treatment system can not completely remove TC 4 , which has caused reports of TC residues in surface water, groundwater and soil around the world, and even in many foods 7 . Therefore, it is of great significance to develop effective methods to remove TC in water environment.To date, there are a lot of techniques such as filtration, ion exchange, adsorption, electrochemical treatment, membrane separation, catalytic degradation, etc. that have been developed ...

Chitosan-Graft-Poly(N-Tert-Butylacrylamide) Copolymer: Synthesis, Characterization and Optimization of Tetracycline Removal Using RSM

“…In other words, the higher the concentration of tetracycline, the more diffusion would consist from the polymer surface to the pores [51]. Similar behavior for the impact of tetracycline concentrations on the uptake capacity of tetracycline was observed and discussed for different adsorbents in the literature [52][53][54]50].…”

Fast Removal of Tetracycline from Aqueous Solution by Aluminosilicate Zeolite Nanoparticles with High Adsorption Capacity

“…Also, increasing the ionic strength may cause the pores of the adsorbent to shrink, thus causing some adsorbates to be unable to enter the pores, reducing the available adsorption sites. 46 Theoretically, under the action of salinization, the solubility of TC in water decreases, and thus a large amount of TC is adsorbed on the surface of the adsorbent, while the actual result is just the contrary. Previous studies note that metal cations in the solution are easily captured by TC.…”

“…Previous studies note that metal cations in the solution are easily captured by TC. 46,47 TC molecules contain amino and hydroxyl groups as electron donor groups and form stable complexes with the metal cations.…”

Oksitetrasiklin hidroklorürün doğal zeolit ile sulu çözeltilerden giderimi

“…Bu da doğal zeoliti çevreleyen filmdeki OTC-HCL moleküllerinin difüzyon hızında artışa neden olur. Enerjideki artışla, OTC-HCL molekülleri doğal zeolitin aktif bölgelerine daha hızlı hareket eder [24]. Bununla birlikte OTC-HCL'nin doğal zeolit ile adsorpsiyonu endotermik bir süreçtir [22].…”