青贮秸秆活性炭的制备和改性及其对阿莫西林的吸附特性

为提高秸秆活性炭性能及其对AMX（阿莫西林）的吸附效果,研究了青贮秸秆活性炭的制备和改性方法及其对AMX的吸附特性.以青贮玉米秸秆为原料,通过响应面法（RSM）,在活化温度为584℃、浸渍比为1:1.9的条件下,制备了AC-S（青贮活性炭）和AC-SA（改性青贮活性炭）.通过比表面积和孔径分析,AC-S和AC-SA的S_BET（比表面积）分别为1 521、1 347 m2/g,两种活性炭兼具中孔和微孔.研究了吸附动力学、热力学特性及初始ρ(AMX)、pH对吸附结果的影响.结果表明,AC-S和AC-SA对AMX的最大吸附量分别为39.69、45.60 mg/L,均符合伪二级动力学模型和Langmuir吸附等温模型（R20.99）,吸附形式主要为化学吸附,在酸性条件下吸附量增加.研究显示,改性后AC-SA的酸性官能团增加45.31%,提高了其与AMX的碱性基团结合能力,因此对AMX的吸附效果更好.      

Preparation and characterization of modified dual network dust suppression gel based on sodium alginate and soluble starch

Aiming at the problems of complex environment and serious dust pollution in large open-pit coal yards, a dust suppression gel with a dual network structure was prepared by modifying the soluble starch and sodium alginate with iron ions. The changes of functional groups, thermal stability, and morphology structure before and after the reaction were analyzed by FTIR, TG-DSC, and SEM, and the formation mechanism of the dual network was revealed by XPS. Furthermore, the water absorption and water retention experiments proved that the dual network structure is more conducive to water retention than the single-layer network. According to molecular dynamics simulations and contact angle experiments, gel and adsorbed water molecules can approach coal dust molecules on their own to contact, wet, and combine with coal dust. The adhesion test proved that the dust suppression gel with iron ions had better adhesion to dust. The anti-freezing test shows that the dust suppression gel has good anti-freezing performance. The antifreeze test shows that the dust suppression gel still has excellent freeze–thaw resistance at the test temperature of??-20℃. The mechanical property test shows that the dust suppressant gel can prevent the product from being damaged by external force. The acid and alkali resistance experiments showed that the acid and alkali resistance of the gel was improved under the condition of iron ion modification, and the flying of coal powder was effectively prevented. This research provides a new theoretical idea for coal dust control in complex environment.

     

Sample preparation methods for the analysis of microplastics in freshwater ecosystems: a review

Environmental Chemistry Letters - The vast amount of plastic waste emitted into the environment is of increasing concern because there is mounting evidence for various toxic effects of...