RESUMEN
In this paper, the effects and mechanism of ciprofloxacin (CIP) degradation with peroxymonosulfate (PMS) catalyzed by solid waste red mud (RM) was firstly studied. The results indicated that RM has large specific surface area (10.96 m2·g-1) and complex pore structure, containing ferric, alumina and calcium oxide, which enhanced ciprofloxacin degradation by PMS effectively. Radical quenching experiments revealed that SO4-·and HO·were contributed to ciprofloxacin oxidation, and the reaction was mainly occurred on RM's surface. An increase in temperature could accelerate CIP degradation, and the corresponding reaction activation energy Ea was about 5.74 kJ·mol-1. Meanwhile, CIP degradation rate increased with PMS concentration and the optimal dosage of RM was 1.0 g·L-1. Eight degradation intermediates were identified using HPLC/MS/MS, and consequently, CIP was degraded mainly through two pathways; the piperazine groups were preferentially attacked by active free radicals. This study further indicated that RM is a cheap catalyst and can be potentially used in the treatment of antibiotic contaminated wastewater.
Asunto(s)
Ciprofloxacina , Contaminantes Químicos del Agua , Peróxidos , Espectrometría de Masas en TándemRESUMEN
OBJECTIVE: To describe the prevalence of aggressive behavior among preschool children and its related family factors. METHODS: 1234 preschool children in ten kindergartens were rated on their aggressive behavior by their parents, using Child Behavior Checklist (CBCI), Parent Behavior Inventory (PBI) and a general questionnaire. RESULTS: The overall prevalence of aggressive behavior among preschool children was 12.9% (95%CI: 11.0 - 15.0) according to the CBCL assessment, with the rate being slight higher (13.7%, 93/680) in boys than in girls (11.9%, 66/554). Data from logistic regression analysis showed that parents' hostile/coercive parenting style (OR = 2.396, 95%CI: 1.636 - 3.510) and inconsistent parenting attitude between parents and grandparents (OR = 1.867, 95%CI: 1.287 - 2.710) would lead to more aggressive behaviors in preschool children. Compared with children without difficulty in falling asleep, those who often (OR = 3.415, 95%CI: 1.901 - 6.135) or sometimes (OR = 2.147, 95%CI: 1.256 - 3.671) had problem falling asleep at night had more aggressive behaviors. On the other hand, factors as: watching TV less than 1 hour each day (OR = 0.252, 95%CI: 0.136 - 0.467), father in older age (OR = 0.703, 95%CI: 0.503 - 0.983) and participating in regular outdoor activities (OR = 0.617, 95%CI: 0.399 - 0.955) were protective factors to the aggressive behaviors of the children. CONCLUSION: The prevalence of aggressive behavior in preschool children was high which called for more attention. Intervention programs targeting the family should consider the influencing factors as ways of parenting, consistent attitude on parenting in the family etc. to reduce the occurrence of aggressive behavior among preschool children.