scholarly journals Effects and Mechanisms of Calcium Ion Addition on Lead Removal from Water by Eichhornia crassipes

2020 ◽  
Vol 17 (3) ◽  
pp. 928 ◽  
Author(s):  
Jin-mei Zhou ◽  
Zhong-cheng Jiang ◽  
Xiao-qun Qin ◽  
Lian-kai Zhang ◽  
Qi-bo Huang ◽  
...  
Keyword(s):  
Calcium Ion ◽  
Eichhornia Crassipes ◽  
Removal Rate ◽  
Metal Availability ◽  
Lead Removal ◽  
Karst Water ◽  
Vascular Bundles ◽  
Karst Areas ◽  
Fibrous Roots ◽  
Floating Plant

Karst water is rich in calcium ions (Ca2+) and exhibits poor metal availability and low biodegradation efficiency. This study sought to analyze the effects and mechanisms of Ca2+ on lead (Pb) removal and absorption by Eichhornia crassipes (a floating plant common in karst areas). Moreover, the morphology and functional groups of E. crassipes in water were characterized via SEM, and FTIR. The results demonstrated that the removal rate of Pb in karst water (85.31%) was higher than that in non-karst water (77.04%); however, the Pb bioconcentration amount (BCA) in E. crassipes roots in karst water (1763 mg/kg) was lower than that in non-karst water (2143 mg/kg). With increased Ca2+ concentrations (60, 80, and 100 mg/L) in karst water, the Pb removal rate increased (85.31%, 88.87%, and 92.44%), the Pb BCA decreased (1763, 1317, and 1095 mg/kg), and the Ca BCA increased (6801, 6955, and 9368 mg/kg), which was attributed to PbCO3 and PbSO4 precipitation and competitive Ca and Pb absorption. High Ca2+ concentrations increased the strength of cation exchange, alleviated the fracture degree of fibrous roots, reduced the atrophy of vascular bundles, protected the cell wall, promoted C–O combined with Pb, enhanced the strength of O‒H, SO42−, C=O, and reduced the oxidization of alkynyl acetylene bonds.

Uptake, Distribution, and Transformation of CuO NPs in a Floating Plant Eichhornia crassipes and Related Stomatal Responses

2017 ◽  
Vol 51 (13) ◽  
pp. 7686-7695 ◽  
Author(s):  
Jian Zhao ◽  
Wenting Ren ◽  
Yanhui Dai ◽  
Lijiao Liu ◽  
Zhenyu Wang ◽  
...  
Keyword(s):  
Eichhornia Crassipes ◽  
Cuo Nps ◽  
Stomatal Responses ◽  
Floating Plant

scholarly journals Assessment of TiO2 photoactivity on the lead removal: kinetic and mechanistic processing

2017 ◽  
Vol 75 (11) ◽  
pp. 2508-2519 ◽  
Author(s):  
Anca Peter ◽  
Anca Mihaly-Cozmuta ◽  
Camelia Nicula ◽  
Leonard Mihaly-Cozmuta
Keyword(s):  
Citric Acid ◽  
Uv Light ◽  
Removal Rate ◽  
Catalyst Particle ◽  
Positive Influence ◽  
Lead Removal ◽  
Starting Solution ◽  
Pseudo Second Order ◽  
High Concentrations ◽  
The Impact

Removal of lead ions from aqueous solutions, in the presence and in absence of commercial TiO2, under UV-light was studied. The influence of catalyst mass, concentration of Pb(II) ions and of citric acid in the starting solution as well as the impact of illumination conditions on the removal rate were also investigated. The results were fitted on the pseudo-first order, pseudo-second order and Elovich kinetic models, Weber-Morris intraparticle and liquid film diffusion models, in order to establish the photoreduction mechanism. The Pb removal rate increased in time by a combined linear-exponential mechanism. The catalyst had a positive influence on the removal rate at the start of the photoreduction. At a low concentration of Pb(II) ions (20 mg/L), the amount of photoreduced Pb(II) ions was proportional to the concentration of the citric acid solution, but at high concentrations (240 mg/L), the correlation was inversely proportional. The rate limiting steps in the removal of lead were both the photoreduction on the TiO2 surface and the diffusion through the film surrounding the catalyst particle. The lead removal was significantly influenced by the mobility and by the concentration of the species in solution.

scholarly journals Process-based karst modelling to relate hydrodynamic and hydrochemical characteristics to system properties

2013 ◽  
Vol 10 (3) ◽  
pp. 2835-2878
Author(s):  
A. Hartmann ◽  
M. Weiler ◽  
T. Wagener ◽  
J. Lange ◽  
M. Kralik ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Large Scale ◽  
Model Parameters ◽  
Karst Water ◽  
Flow Duration ◽  
Karst Areas ◽  
Flow Duration Curves ◽  
System Properties ◽  
Karst Systems ◽  
Sensitive Parameters

Abstract. More than 30% of Europe's land surface is made up of karst exposures. In some countries, water from karst aquifers constitutes almost half of the drinking water supply. Hydrological simulation models can predict the large-scale impact of future environmental change on hydrological variables. However, the information needed to obtain model parameters is not available everywhere and regionalisation methods have to be applied. The responsive behaviour of hydrological systems can be quantified by individual metrics, so-called system signatures. This study explores their value for distinguishing the dominant processes and properties of five different karst systems in Europe and the Middle East with the overall aim of regionalising system signatures and model parameters to ungauged karst areas. By defining ten system signatures derived from hydrodynamic and hydrochemical observations, a process-based karst model is applied to the five karst systems. In a stepwise model evaluation strategy, optimum parameters and their sensitivity are identified using automatic calibration and global variance-based sensitivity analysis. System signatures and sensitive parameters serve as proxies for dominant processes and optimised parameters are used to determine system properties. To test the transferability of the signatures, they are compared with the optimised model parameters and simple climatic and topographic descriptors of the five karst systems. By sensitivity analysis, the set of system signatures was able to distinguish the karst systems from one another by providing separate information about dominant soil, epikarst, and fast and slow groundwater flow processes. Comparing sensitive parameters to the system signatures revealed that annual discharge can serve as a proxy for the recharge area, that the slopes of the high flow parts of the flow duration curves correlate with the fast flow storage constant, and that the dampening of the isotopic signal of the rain as well as the medium flow parts of the flow duration curves have a non-linear relation to the distribution of groundwater dynamics. Even though, only weak correlations between system signatures and climatic and topographic factors could be found, our approach enabled us to identify dominant processes of the different systems and to provide directions for future large-scale simulation of karst areas to predict the impact of future change on karst water resources.

scholarly journals Feasibility of Remediation Lead, Nickel, Zinc, Copper, and Cadmium-Contaminated Groundwater by Calcium Sulfide

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2266
Author(s):  
Chin-Yuan Huang ◽  
Pei-Cheng Cheng ◽  
Jih-Hsing Chang ◽  
Yu-Chih Wan ◽  
Xiang-Min Hong ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Metal Contamination ◽  
Removal Rate ◽  
Contaminated Groundwater ◽  
Lead Removal ◽  
In Situ Stabilization ◽  
Nickel Zinc ◽  
Calcium Polysulfide ◽  
Lead Nickel

Metal contamination in groundwater often occurs in various industrial processes. Studies have confirmed that polysulfide could reduce hexavalent chromium to trivalent chromium, achieving the effect of in situ stabilization. For other metal contamination in groundwater, whether polysulfide also had a stabilizing ability to achieve in situ remediation. This research focused on metals in addition to chromium that often contaminated groundwater, including lead, nickel, zinc, copper, and cadmium, to explore the feasibility of using calcium polysulfide (CaSx) as an in situ stabilization technology for these metals’ contamination of groundwater. Results showed that CaSx had a great removal efficiency for metals lead, nickel, zinc, copper, and cadmium. However, for nickel, zinc, copper, and cadmium, when CaSx was added excessively, complexes would be formed, causing the result of re-dissolution, in turn reducing the removal efficiency. As it is difficult to accurately control the dosage of agents for in situ groundwater remediation, the concentration of re-dissolved nickel, zinc, copper, and cadmium may not be able to meet the groundwater control standards. CaSx had high lead removal efficiency and for a concentration of 100 mg/L, the dose of calcium polysulfide was more than the amount of 1/1200 (volume ratio of CaSx to groundwater). In addition, the removal rate was almost 100% and it would not cause re-dissolution due to excessive CaSx dosing. CaSx can be used as an in situ stabilization technique for lead-contaminated groundwater.

A COMPARISON OF THE GENETIC SHAFT TYPES OF SOME KARST AREAS BASED ON THEIR SPECIFIC SHAFT LENGTHS

2020 ◽  
Vol 1 (3) ◽  
Author(s):  
Márton Veress ◽  
András Hegedűs ◽  
Pavle Cikovac ◽  
Ruban Dmitry A. ◽  
Kálmán Péntek
Keyword(s):  
Vadose Zone ◽  
High Mountain ◽  
Karst Water ◽  
Shaft Length ◽  
Water Influx ◽  
Karst Areas ◽  
Type 3 ◽  
Specific Length

Shaft development can be documented on the basis of comparative studies of specific shaft lengths and shaft patterns. We calculated the specific length of shafts and the average specific shaft length of the shafts in some karst areas and we investigated the relation between the altitude of shaft floors and the specific shaft length. Taking the registered specific shaft lengths and the shaft patterns into consideration, it can be stated that some parts of the shafts developed paragenetically in the studied karst areas. In the Bakony Region, this was caused by surface water influx, rise of karst water level, and their simultaneous effect. As a result, shaft systems, bifurcating shafts and storeyed shafts developed. On glaciokarst areas, shafts may constitute a system with phreatic passages: either because a phreatic environment developed in the vadose zone due to the permanent impoundment of karst water or because a phreatic passage got into the vadose zone since the karst became elevated. On the studied karst areas, the following shaft development types are distinguished: glacial-high mountain surface flood development type (1), glacial-high mountain karst water and surface flood development type (2), glacial karst water and surface flood later phreatic development type (3), shaft with a passage that got into the vadose zone (4).

scholarly journals Living with floating vegetation invasions

AMBIO ◽  
2020 ◽  
Vol 50 (1) ◽  
pp. 125-137 ◽  
Author(s):  
Fritz Kleinschroth ◽  
R. Scott Winton ◽  
Elisa Calamita ◽  
Fabian Niggemann ◽  
Martina Botter ◽  
...  
Keyword(s):  
Eichhornia Crassipes ◽  
Environmental Benefits ◽  
Societal Costs ◽  
Nutrient Sources ◽  
Urban Land Cover ◽  
Plant Coverage ◽  
Floating Vegetation ◽  
Negative Impacts ◽  
Water Hyacinths ◽  
Floating Plant

AbstractInvasions of water bodies by floating vegetation, including water hyacinth (Eichhornia crassipes), are a huge global problem for fisheries, hydropower generation, and transportation. We analyzed floating plant coverage on 20 reservoirs across the world’s tropics and subtropics, using > 30 year time-series of LANDSAT remote-sensing imagery. Despite decades of costly weed control, floating invasion severity is increasing. Floating plant coverage correlates with expanding urban land cover in catchments, implicating urban nutrient sources as plausible drivers. Floating vegetation invasions have undeniable societal costs, but also provide benefits. Water hyacinths efficiently absorb nutrients from eutrophic waters, mitigating nutrient pollution problems. When washed up on shores, plants may become compost, increasing soil fertility. The biomass is increasingly used as a renewable biofuel. We propose a more nuanced perspective on these invasions moving away from futile eradication attempts towards an ecosystem management strategy that minimizes negative impacts while integrating potential social and environmental benefits.

scholarly journals Efficiency of Pb, Zn, Cd, and Mn Removal from Karst Water by Eichhornia crassipes

2020 ◽  
Vol 17 (15) ◽  
pp. 5329
Author(s):  
Jin-Mei Zhou ◽  
Zhong-Cheng Jiang ◽  
Xiao-Qun Qin ◽  
Lian-Kai Zhang ◽  
Qi-Bo Huang ◽  
...  
Keyword(s):  
Eichhornia Crassipes ◽  
Aquatic Plant ◽  
Bioconcentration Factor ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Translocation Factor ◽  
Plant Morphology ◽  
Plant Functional Groups ◽  
Karst Water ◽  
Mn Concentrations

This study experimentally investigated heavy metal removal and accumulation in the aquatic plant Eichhornia crassipes. Pb, Zn, Cd, and Mn concentrations, plant morphology, and plant functional groups were analyzed. Eichhornia crassipes achieved high removal efficiency of Pb and Mn from karst water (over 79.5%), with high proportion of Pb, Zn, and Cd absorption occurring in the first eight days. The highest removal efficiencies were obtained at initial Pb, Zn, Cd, and Mn concentrations of 1 mg/L, 2 mg/L, 0.02 mg/L, and 0.2 mg/L, respectively. Eichhornia crassipes exhibited a high bioconcentration factor (Mn = 199,567 > Pb = 19,605 > Cd = 3403 > Zn = 1913) and a low translocation factor (<1). The roots accumulated more Pb, Zn, Cd, and Mn than the stolons and leaves due to the stronger tolerance of roots. The voids, stomas, air chambers, and airways promoted this accumulation. Pb, Cd, Zn, and Mn likely exchanged with Mg, Na, and K through the cation exchange. C≡C, C=O, SO42−, O-H, C-H, and C-O played different roles during uptake, which led to different removal and accumulation effects.

Study on Energy Consumption Distribution of High Ferric-Based Silicon Coagulant Using Fractal Dimension

2013 ◽  
Vol 295-298 ◽  
pp. 1389-1392
Author(s):  
Lei Cheng ◽  
Yan Zhen Yu ◽  
Juan Tan ◽  
Yong Sun
Keyword(s):  
Fractal Dimension ◽  
Energy Consumption ◽  
Industrial Wastewater ◽  
Removal Rate ◽  
Orthogonal Experiment ◽  
Lead Ion ◽  
Lead Removal ◽  
Optimum Conditions ◽  
Stirring Time ◽  
Rapid Stirring

High ferric-based silicon coagulant is a kind of new self-made coagulant. The high ferric content was introduced in the preparation process of the coagulant, and the effect was good in dealing with simulated industrial wastewater with lead. The beaker test indicated that the lead removal rate reached the highest 96.48% when the rapid stirring speed was 300r/min and stirring time was 1min, low stirring speed was 80r/min and stirring time was 15min, the dosage of the coagulant was 3.5ml/L. And the fractal dimension of flocs was 1.67674 under that optimum conditions. The low stirring stage was divided into three different stages in the orthogonal experiment of energy consumption, and the result showed that the optimum combination of flocculation was: velocity gradient G1=67.7s-1, stirring time T1=4min; G2=57.8 s-1, T2=5min; G3=23.9s-1, T3=6min. The removal rate of lead ion improved and the energy consumption decreased when the flocculation was divided into different stages. The relations between fractal dimension and energy consumption distribution can be obtained by calculated the fractal dimension of different stages. The stirring speed can be controlled and the flocs can be prevented from being broken by observing the flocs.

scholarly journals Water Distribution and Silt Clogging in the Strong-Seepage Zone Infiltration Process of Yufuhe River from Yellow River Water Based on the Two-Dimensional Sand Tank Model

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1200
Author(s):  
Weidong Zhao ◽  
Weiping Wang ◽  
Shuai Liu ◽  
Shisong Qu ◽  
Xiuxiu Sun ◽  
...  
Keyword(s):  
River Water ◽  
Water Distribution ◽  
Yellow River ◽  
Removal Rate ◽  
Suspended Particles ◽  
Suspended Solid ◽  
Karst Water ◽  
Two Dimensional ◽  
Infiltration Process ◽  
Tank Model

A two-dimensional sand tank experiment was designed to explore the mechanism of water distribution and silt clogging of Yellow River water whilst replenishing groundwater in ‘open window’ reach of the piedmont river and strong seepage area consisting of a gravel and karst layer from top to bottom. Water released through the reach was divided into surface, pore and fracture karst water, of which karst water was an effective recharge from the surface water. A reasonable released water plan is necessary in recharging to avoid invalid recharge. The karst water accounted for 60–70% of the amount of water released before clogging, and this value was reduced to approximately 10–20% whilst a thin clay layer formed from suspended particles on the surface layer of the medium after clogging. The removal rate of suspended solids along vertical and lateral directions in the medium can reach over 96%. The retained amount of suspended particles was mainly distributed on the surface and upper layer region of the medium. A rubber dam can improve effective infiltration whilst promoting suspended solid deposition in the medium. The fitting degree of the numerical simulation and measured results was above 0.9, which proves the reliability of the sand tank model results.

scholarly journals AQUATIC PLANT (HYDRILLA VERTICILLATA) ROLES IN BIOACCUMULATION OF HEAVY METALS

2020 ◽  
Vol 51 (2) ◽  
pp. 574-584
Author(s):  
Al-Zurfi & Al-Tabatabai
Keyword(s):  
Heavy Metals ◽  
Aquatic Plant ◽  
Removal Rate ◽  
Hydrilla Verticillata ◽  
Bioaccumulation Factor ◽  
Lead Removal ◽  
Removal Ratio ◽  
Cadmium And Lead

The current study was aimed to test the ability of Hydrilla verticillata plant ability to accumulated of cadmium and lead in its tissues. The plant was treated with different concentrations of cadmium (1,2,4,8) ppm and lead (0.5,5,10,20) ppm for 21 days'. The concentration of metals was measured in plant and water, Bioaccumulation factor and removal ratio were also measured during days (1,7,14,21), as well as measured biomass and length of the plant were measured at the end of the experiment. The results were shown that the highest cadmium and lead removal rate were (77, 88) % at concentration (4, 10) ppm during (21, 7) days, respectively, also the bioaccumulation factor (BCF) of the two metals were (21639 and 45467) at concentrations (4 and 0.5) ppm during the 21st day of the experiment respectively. The biomass of plant in treated aquarium with different concentrations of cadmium showed a decrease during the experimental days, while increased in biomass of plant treated aquarium with different concentrations of lead. The length rate of the plant was significantly reduced in the plant that treated with cadmium but significant increase in plant treated with lead compared to the control.

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