Effectiveness of hydrous manganese dioxide （δMnO2） adsorbing humic acid under different conditions and its subsequent effects on trihalomethane （THMs） formation have been studied. Humicacid removal increases with...Effectiveness of hydrous manganese dioxide （δMnO2） adsorbing humic acid under different conditions and its subsequent effects on trihalomethane （THMs） formation have been studied. Humicacid removal increases with higher pH and residual TOC decreases from 3.63 mg/L to 1.68 mg/L with pH increasing from 5.5 to 8.5 at 3.0 mg/L δMnO2; δMnO2 exhibits good potential of removing humic acid and the adsorbing potential as high as 1 mg TOC/mg δMnO2 is achieved; the fractional reduction of humic acid with higher molecular weight is about 30% higher than that with lower molecular weight. δMnO2 adsorption obviously reduces subsequent THMs formation; more significant THMs formation reduction is observed for humic acid with higher molecular weight. δMnO2 adsorption is an important factor that contributes to humic acid removal and THMs formation reduction in permanganate pre-oxidation process.展开更多
This study focuses on the effectiveness of hydrous manganese dioxides （ζMnO2） removing arsenite （As（Ⅲ）） from aqueous solution. Effects of such factors as permanganate oxidation, pH, humic acid and Ca^2＋ on As...This study focuses on the effectiveness of hydrous manganese dioxides （ζMnO2） removing arsenite （As（Ⅲ）） from aqueous solution. Effects of such factors as permanganate oxidation, pH, humic acid and Ca^2＋ on As removal and possible mechanisms involved in have been investigated. Permanganate oxidation increases As removal to a certain extent; the higher pH results in the formation of more easily adsorbed As species, contributing to higher As removal; hmnic acid occupies adsorbing sites and decreases ζ potential of ζMnO2, therefore inhibiting As removal; Ca^2＋ facilitates As adsorption on ζMnO2, mainly through increasing ζ potential and decreasing repulsive forces between As and surface sites.ζMnO2 exhibits oxidative and adsorptive potential for As（Ⅲ）, and may be employed as adsorbents or filter coating for As removal in water treatment process.展开更多
Rapid mixing and chlorine saving are two important problems that most drinking water industries are focus on, and this paper adopts chemical induction unit to compare with water jet injector to study what merits chemi...Rapid mixing and chlorine saving are two important problems that most drinking water industries are focus on, and this paper adopts chemical induction unit to compare with water jet injector to study what merits chemical induction unit has. The experiment chose coefficient of variability of chlorine concentration to evaluate the mix effect and used chlorine consumption to compare the two equipments. Distribution reservoir experiments show that chemical induction unit can completely mix chlorine less than 6.2 seconds and water jet injector can not completely mix in 3 minutes. Mixing pool experiments show that chemical induction unit can save chlorine compared with water jet injector, and can save more if more chlorine is consumed.展开更多
This paper briefly introduced the evolution of purification technology for drinking water over time. After description of the 1st generation processes in the beginning of the 20th century - conventional processes and ...This paper briefly introduced the evolution of purification technology for drinking water over time. After description of the 1st generation processes in the beginning of the 20th century - conventional processes and the 2nd generation processes in 1970s - advanced treatment processes, a tertiary processes - UF (ultrafiltration) based on integrated processes was proposed. Moreover, reaction measures (dosing variety of regents for different contaminants) for urban source water emergencies were illustrated in brief. A new technology of KMnO4 and potassium permanganate composite (PPC) for drinking water purification which was developed by Harbin Institute of Technology (HIT) was concisely introduced.展开更多
文摘Effectiveness of hydrous manganese dioxide （δMnO2） adsorbing humic acid under different conditions and its subsequent effects on trihalomethane （THMs） formation have been studied. Humicacid removal increases with higher pH and residual TOC decreases from 3.63 mg/L to 1.68 mg/L with pH increasing from 5.5 to 8.5 at 3.0 mg/L δMnO2; δMnO2 exhibits good potential of removing humic acid and the adsorbing potential as high as 1 mg TOC/mg δMnO2 is achieved; the fractional reduction of humic acid with higher molecular weight is about 30% higher than that with lower molecular weight. δMnO2 adsorption obviously reduces subsequent THMs formation; more significant THMs formation reduction is observed for humic acid with higher molecular weight. δMnO2 adsorption is an important factor that contributes to humic acid removal and THMs formation reduction in permanganate pre-oxidation process.
文摘This study focuses on the effectiveness of hydrous manganese dioxides （ζMnO2） removing arsenite （As（Ⅲ）） from aqueous solution. Effects of such factors as permanganate oxidation, pH, humic acid and Ca^2＋ on As removal and possible mechanisms involved in have been investigated. Permanganate oxidation increases As removal to a certain extent; the higher pH results in the formation of more easily adsorbed As species, contributing to higher As removal; hmnic acid occupies adsorbing sites and decreases ζ potential of ζMnO2, therefore inhibiting As removal; Ca^2＋ facilitates As adsorption on ζMnO2, mainly through increasing ζ potential and decreasing repulsive forces between As and surface sites.ζMnO2 exhibits oxidative and adsorptive potential for As（Ⅲ）, and may be employed as adsorbents or filter coating for As removal in water treatment process.
文摘Rapid mixing and chlorine saving are two important problems that most drinking water industries are focus on, and this paper adopts chemical induction unit to compare with water jet injector to study what merits chemical induction unit has. The experiment chose coefficient of variability of chlorine concentration to evaluate the mix effect and used chlorine consumption to compare the two equipments. Distribution reservoir experiments show that chemical induction unit can completely mix chlorine less than 6.2 seconds and water jet injector can not completely mix in 3 minutes. Mixing pool experiments show that chemical induction unit can save chlorine compared with water jet injector, and can save more if more chlorine is consumed.
文摘This paper briefly introduced the evolution of purification technology for drinking water over time. After description of the 1st generation processes in the beginning of the 20th century - conventional processes and the 2nd generation processes in 1970s - advanced treatment processes, a tertiary processes - UF (ultrafiltration) based on integrated processes was proposed. Moreover, reaction measures (dosing variety of regents for different contaminants) for urban source water emergencies were illustrated in brief. A new technology of KMnO4 and potassium permanganate composite (PPC) for drinking water purification which was developed by Harbin Institute of Technology (HIT) was concisely introduced.
