Environmental Earth Sciences
·
2022
·Vol. 81
·期 16
·1-12
·
IF 3.119
Feng Wenchao,Wu Jun,Lu Jian
The high concentration of manganese (Mn 2+ ) in geothermal water will seriously reduce its utilization rate. Manganese sand has been used to rapidly remove Mn 2+ from water. This study investigated the long-term removal of Mn 2+ from simulated geothermal water by manganese sand filtration column system. The average Mn 2+ removal rate from simulated water with the inlet water temperature of 25, 50, 70 °C were 87.4%, 96.2% and 99.0% during the operation of 90 days. The effluent pH did not change much compared with influent pH value (7.6–8.0). The Mn 2+ removal rates during the operation of 90 days with influent concentration of 1, 10, 20 and 50 mg/L were respectively 98.2%, 99.8%, 91.4% and 63.4%. The average removal rates of Mn 2+ were respectively 99.8% and 94.0% with the influent flow of 5.2 mL/min and 10.4 mL/min. The temperature change in the manganese sand filtration column was further explored in this paper. The experiment of filtration column heated/non-heated showed that the manganese sand filtration column heated had a better effect of removal which could run for 152 days. The dispersion coefficient ( D ) analysis derived from inverse modeling showed that a small temperature change in the filtration column system was conducive to the homogenization of manganese sand medium in the column. The Mn 2+ removal process of manganese sand filtration column heated was proposed. Surface characteristics analysis of manganese sand in the column after reaction showed that Mn 2+ removal mainly occurred in the upper part of the filter column. The surface material of manganese sand in the filtration column heated after operation was manganese oxide material mainly composed of Mn 2 O 3 and MnO 2 . These findings suggested the potential of manganese sand in the engineering application of removing Mn 2+ in geothermal water.
研究领域:
环境科学
·
水处理工程
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Qiao Wang,Mengyao Xiao,Ken Fang,Xing Du,Zhihong Wang,Xinglin Lu
Manganese is widely distributed in the natural environment, and its presence in drinking water poses a risk to human health. In this study, an integrated pre-deposited powdered activated carbon (PAC) and manganese oxide (MnO x ) bio-functional layer of inorganic origin was coupled with gravity-driven ceramic membrane (GDCM) reactor. The study aims to investigate the effects of the membrane pore size and functional layer integrity on the Mn 2+ removal and flux. The results reveal that the average Mn 2+ removal efficiency of the large pore size membranes (300 kDa and 0.45 μm) was lower (75 % – 78 %) compared to those with smaller pores (15 kDa and 50 kDa) (87 % – 88 %) during long-term operation. Such differences are attributed to a period of manganese leakage before the PAC-MnO x matured in large-pore membrane units and a longer residence time in small-pore membranes. The functional layer leaded to reversible fouling, which was more prominent in membranes with larger pores (contributing to 93 % of total resistance) than those with smaller ones (ranging from 51.7 % to 61.9 %). Although the damaged functional layer resulted in occasional high Mn 2+ concentrations in the effluent, it did not significantly impact long-term flux development. Optical coherence tomography (OCT), in conjunction with COMSOL analysis, non-destructively evaluate biofilm formation process and indicate a homogeneous flow field and mass transfer in the “dual layers” (active film layer and ceramic membrane layer) of the GDCM. The presence of manganese-oxidizing bacteria ( Hyphomicrobium, Reyranella, and Pseudomonas ) in the GDCM reactor was verified using confocal laser scanning microscopy (CLSM) and high-throughput sequencing. Additional material characterization revealed that a portion of the PAC-MnO x exhibited characteristics of birnessite, with autocatalytic oxidation of Mn 2+ , and that Mn (III) and Mn (IV) were the primary species in MnO x , which exhibited excellent catalytic oxidation and adsorption capabilities for Mn (II), respectively. Overall, the developed PAC-MnO x GDCM system shows great promise in efficiently removing manganese and producing water of desired quality, thereby holding potential in applications across several sectors of advanced water treatment processes.
研究领域:
环境工程
·
水处理技术
✓ 已验证
产品关联
DOI
高影响因子
Water
·
2023
·Vol. 15
·期 12
·2145
·
IF 3.4
Lichao Nengzi,Lin Meng,Yong Qiu,Xiaoju Li,Keniu Didi,Haitao Li,Guanglei Qiu
Nitrite produced during ammonia oxidation can inhibit the activity of microorganisms. To provide guidance for the optimization and design of a biofilter, a pilot-scale biofilter was established to investigate the influence of nitrite on organic matter and manganese removal and on the kinetics. The results demonstrated that CODMn, ammonia, and manganese in effluent were 2.77, 0.034, and 0.026 mg/L in the steady phase, respectively. Organic matter and manganese removal were affected by nitrite during the start-up process, as well as in the ammonia increasing process. When ammonia increased from about 0.5 to 1 and 2 mg/L, organic matter, and manganese removal were affected at 4 and 3 days and 6 and 5 days, respectively. When organic matter, ammonia, and manganese in the influent were 6.27, 2.07, and 1.19 mg/L, respectively, organic matter, ammonia, and manganese oxidation all followed a first-order kinetic rate. Thek-value was 0.0268, 0.268, and 0.216 min−1, and the half-life time was 24.236, 2.583, and 3.202 min, respectively. The influence of nitrite on the structure of microbial communities in the biofilter will be investigated in the future.Keywords:organic matter;ammonia and manganese removal;biofilter;nitrite;drinking water;kinetics
研究领域:
环境生物学
·
水处理工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2022
·
IF 4.432
Wenyan Song,Tianfeng Huang,Huajiang Zuo,Dongmei Deng,Chunyi Tang
Environmentally friendly natural materials, chitosan (CS) and tannic acid (TA), were used to prepare a composite membrane and immobilize Stenotrophomonas maltophilia on it, which was then applied for removing manganese in water. Surface morphology was investigated, and the amount of immobilized fungus on the composite membrane was probed using scanning electron microscopy (SEM). A composite membrane was prepared by grafting CS and TA on a cotton cloth, and the experimental conditions were optimized; preferential immobilization of S. maltophilia on the composite was achieved. A Mn 2+ standard calibration curve was obtained via atomic absorption spectroscopy ; the removal of manganese ions was determined and compared before and after immobilization on the composite membrane. For glutaraldehyde concentration of 8%, solution pH of 5, TA concentration of 0.05 g/mL, and temperature of 80 °C, the grafting of the TA/CS composite membrane was the best, resulting in better immobilization of S. maltophilia . SEM images showed that a large number of S. maltophilia were immobilized on the composite membrane, substantially improving the manganese removal performance. The removal rate of the manganese ions was the best and reached >70% for solution pH of 5 and Mn 2+ concentration of 0.6–1.2 mg/L.
研究领域:
环境科学
·
水处理
·
微生物学
✓ 已验证
产品关联
DOI
高影响因子
WATER AIR AND SOIL POLLUTION
·
2024
·Vol. 235
·期 11
·1-22
·
IF 3.8
Zhang Liping,Wang Weiwei,Guo Xiangshuai,Wang Lifang,Chen Jiale,Cui Xingjian,Li Huitong
Iron and Manganese pollution were widespread in the water of northern Chinese mines, exacerbating regional water scarcity and potential ecological issues. This study aimed to remove dissolved iron and manganese from acid mine water using serpentine-loaded manganese oxide (Serp-MO) prepared by a simple coprecipitation-loaded metal method. Serp-MO was microscopically characterized, and the adsorption performance and adsorption mechanism of the Serp-MO composite adsorbent for Fe 2+ and Mn 2+ were analyzed. After loading, the specific surface area and pore volume of the particles significantly increased, and the surface pore structure improved, which was conducive to the simultaneous adsorption and removal of iron and manganese. The optimal reaction conditions for Serp-MO treatment of composite water samples with Fe 2+ and Mn 2+ mass concentrations of 20 mg/L and 5 mg/L respectively, were as follows: dosage of Serp-MO 550 mg/L, temperature 35 ℃, oscillation rate 180 r/min, and reaction time 140 min. Under these conditions, the removal rates of Fe 2+ and Mn 2+ were 99.8% and 99.6%, respectively. The presence of coexistence cations Zn 2+ and Cu 2+ can inhibit the removal of Fe 2+ and Mn 2+ by Serp-MO, while SO 4 2- can promote the removal. The pseudo-second-order kinetic model and Langmuir isothermal adsorption model well described the adsorption process of Fe 2+ and Mn 2+ by the Serp-MO. The maximum adsorption capacities of Serp-MO for Fe 2+ and Mn 2+ were 14.31 mg/g and 24.04 mg/g, representing improvements of 470.12% and 626.28%, respectively, compared to Serp-MO. The adsorption thermodynamics showed that ΔG was <0 and ΔH and ΔS were greater than 0 at all test temperatures, which was an entropy-increasing reaction, and that increasing the temperature was favorable for the removal of Fe 2+ and Mn 2+ . Based on the analysis of adsorption products, Serp-MO primarily facilitates the precipitation of iron in water, while the removal of manganese was mainly by adsorption. A regeneration study over five cycles indicated that Serp-MO possessed promising reusability potential. Furthermore, the safety leaching test indicated that the material caused minimal secondary pollution.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Sitong Liu,Kun Feng,Dawei Zhang,Yang Liu,Jing Wang,Baiyun Lu,Defeng Xing
Understanding the stability and assemblage of biofilm microbiomes under oligotrophic conditions is critical for improving groundwater bioremediation. In this study, a novel microbial electrochemical filter (MEF) was developed to explore the impact of weak electrical stimulation on functional adaptability of biofilms under oligotrophic and 1,4-dioxane exposure conditions. Under 20 mg/L 1,4-dioxane stress, the MEF achieved 94.72 % manganese removal and 27.27 % ammonia nitrogen removal, while the conventional biofilter exhibited 88.76 % manganese removal with negligible ammonia nitrogen removal. Metagenomics analyses revealed that dominant populations in the MEF included Nitrospira , Bradyrhizobium , and Nitrosomonas , with relative abundance of 6.23 −10.78 %, 5.81 −6.15 %, and 1.62 −5.58 %, respectively. Weak electrical stimulation enriched the manganese oxidation-associated genes cotA , mnxG , and mcoA , whose total relative abundances being 6.3 times that of the conventional biofilter before dioxane exposure and 2.0 times after exposure. Genes encoding ammonia monooxygenase ( amoABC ), hydroxylamine dehydrogenase ( hao ) increased by 2.4- and 1.9-fold, respectively, compared to the conventional biofilter. Additionally, genes involved in the reductive tricarboxylic acid cycle and nitrogen fixation were twice as abundant in the MEF than in the conventional biofilter, suggesting enhanced nutrients availability for heterotrophic bacteria during start-up. These findings demonstrated that weak electrical stimulation effectively regulated biofilm microbiomes and enhance pollutant removal in MEF under oligotrophic conditions.
研究领域:
环境生物技术
·
微生物生态学
·
水处理技术
·
宏基因组学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）