Halloysite nanotubes, a naturally occurring nanomaterial with a unique tubular morphology, have shown considerable potential for heavy metal remediation. However, significant inconsistencies in the reported maximum adsorption capacities (qmax) for heavy metal ions—such as Pb2+, which ranges from 7.5 to 84.0 mg/g with a coefficient of variation (CV) of 68%—have severely hindered both scientific understanding and practical application of this promising material. To address this critical knowledge gap, we conducted a reassessment using carefully selected halloysite specimens from three geologically distinct deposits (Utah, USA; Henan and Yunnan, China). Under rigorously controlled experimental conditions, we precisely quantified the adsorption capacities of halloysite for Cd2+, Zn2+, and Pb2+. Through an integrated multi-technique characterization approach involving XRF, XRD, FTIR, TEM, and BET analyses, we identified two fundamental crystallochemical parameters that govern the adsorption performance of halloysite: the degree of lattice substitution and the density of surface hydroxyl groups. Our findings reveal that optimal heavy metal adsorption occurs in halloysite with lower lattice substitution and higher surface hydroxyl density. This work not only provides a reliable range of adsorption capacities for halloysite but, more importantly, establishes a scientific foundation for optimizing the application of halloysite in heavy metal remediation.
Mingming Zhou,Siew Young Quek,Xulan Shang,Shengzuo Fang
This research investigated the variations of triterpenoid contents in Cyclocarya paliurus leaves and their underlying anticancer activity and mechanism. Leaf samples were collected from twelve geographical locations in China for the experiments. Significant variation in the triterpenoid content and growth inhibition on HeLa cells were observed among the C. paliurus populations. Antiproliferation effects of the leaf samples were significantly affected by the pentacyclic triterpenoids contents except for oleanolic acid. Among the pentacyclic triterpenoids, hederagenin exhibited the best anticancer activity with IC 50 of 17.42 μg/mL. Based on the results, pentacyclic triterpenoids may induce HeLa cell apoptosis via mitochondrial pathway. RNA sequencing indicated that the ACTB , ATF4 , TUBA1B and TUBA1C genes might be the key ones involved in the apoptosis induction by cyclocaric acid B and hederagenin. These results provided useful information for application of C. paliurus in functional beverage and pharmaceutical industries.
The sex pheromone of the oriental armyworm, Mythimna separata (Walker), in China has always been confusing. It was initially considered as cis-11-hexadecenal (Z11-16:Ald) or cis-11-hexadecenyl acetate (Z11-16:Ac) and cis-11-hexadecenol (Z11-16:OH), as well as a mixture of these compounds. However, inconsistent results have frequently occurred using these compounds or mixtures in field trapping. Through gland analysis from individual females and nationwide field experiments, we identified two distinct types: Z11-16:Ald (aldehyde type or A type) and a mixture of Z11-16:Ac and Z11-16:OH (ester type or E type). Electroantennography (EAG) results indicated that both strains of males co-existed in the field. A strain of males had a strong EAG response to Z11-16:Ald but weak responses to Z11-16:Ac and Z11-16:OH, whereas E strain males had strong responses to Z11-16:Ac and Z11-16:OH but a weak response to Z11-16:Ald. Z11-16:OH identified in female E strain inhibited the attraction of A strain males to A type pheromones. Both A and E types of sex pheromone were respectively formulated and field evaluation (2014-2021) across > 20 provinces from southern to northern China showed geographic and generational variations. During overwintering, E strain males were predominantly caught in Hainan, Fujian, and Guangdong provinces, while A strain males were mainly trapped in Guangxi, Anhui, Sichuan, Jiangsu, and Jiangxi provinces. Subsequent generations exhibited mixed populations in most regions. These findings suggest regional adaptation and migration-driven hybridization. The study highlights the necessity of strain-specific pheromone blends for effective monitoring and control. This work resolves long-standing ambiguities in M. separata sex pheromone ecology.
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