scholarly journals Nutrient and Tetracycline Removal From Simulated Biogas Slurry and Biogas Upgrading by Microalgae Cultivation Under Different Carbon Nanotubes Concentration

Author(s):  
Li Sun ◽  
Chunzhi Zhao ◽  
Shiqing Sun ◽  
Changwei Hu ◽  
Yongjun Zhao ◽  
...  

Abstract The present study aimed to determine the effects of multi-walled carbon nanotubes (MWCNTs) concentrations (0, 0.1, 1, 5, 10 mg·L− 1) on tetracycline (TC) and biogas slurry nutrients removal by microalgae Chlorella vulgaris cultivation. Treatments with 1 mg·L− 1 MWCNTs yielded maximum dry weight and cells quantity of 0.81 ± 0.008 g·L− 1 and 5.83×107 cell·L− 1, respectively. The results of chlorophyll a were consistent with rapid fluorescence induction kinetics (OJIP-test), indicating that moderate MWCNTs concentration could enhance microalgal photosynthesis. Maximum chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), tetracycline (TC), and CO2 removal efficiencies were 90.43 ± 5.15%, 78.12 ± 4.33%, 77.07 ± 4.12%, 89.64 ± 3.08%, and 64.26 ± 0.71%, respectively when treated with 1 mg·L− 1 MWCNTs. Of the five MWCNTs concentrations set in this study, the optimal concentration was 1 mg·L− 1 for nutrient and CO2 removal efficiencies. These results indicated that moderate MWCNTs concentrations would promote tetracycline and nutrients removal by enhancing Chlorella vulgaris photosynthesis activity.

Author(s):  
Katrin Weise ◽  
Thomas Kurth ◽  
Irina Politowski ◽  
Carola Winkelmann ◽  
Andreas Schäffer ◽  
...  

Abstract Although the development and application of nanomaterials is a growing industry, little data is available on the ecotoxicological effects on aquatic organisms. Therefore, we set up a workflow to address the potential uptake of weathered multi-walled carbon nanotubes (wMWCNTs) by a model organism, the pulmonary mud snail Lymnaea stagnalis (L. stagnalis), which plays an important role in the food web. It represents a suitable organism for this approach because as a grazer it potentially ingests large amounts of sedimented wMWCNTs. As food source for L. stagnalis, benthic biofilm was investigated by the use of a transmission electron microscope (TEM) and a scanning electron microscope (SEM) after exposure with wMWCNTs. In addition, isotopic labeling was applied with 14C-wMWCNTs (0.1 mg/L) to quantify fate, behavior, and enrichment of 14C-wMWCNTs in benthic biofilm and in L. stagnalis. Enrichment in benthic biofilm amounted to 529.0 µg wMWCNTs/g dry weight and in L. stagnalis to 79.6 µg wMWCNTs/g dry weight. A bioconcentration factor (BCF) for L. stagnalis was calculated (3500 L/kg). We demonstrate the accumulation of wMWCNTs (10 mg/L) in the digestive tract of L. stagnalis in an effect study. Moreover, the physiological markers glycogen and triglycerides as indicators for the physiological state, as well as the RNA/DNA ratio as growth indicator, were examined. No significant differences between exposed and control animals were analyzed for glycogen and triglycerides after 24 days of exposure, but a decreasing trend is recognizable for triglycerides. In contrast, the significant reduction in the RNA/DNA ratio of L. stagnalis indicated an inhibition of growth with a following recovery after depuration. The described workflow enables a comprehensive determination of the fate and the behavior of wMWCNTs specifically and in general all kinds of CNTs in the aquatic environment and therefore contributes to a holistic risk assessment of wMWCNTs.


2013 ◽  
Vol 666 ◽  
pp. 33-42 ◽  
Author(s):  
Meng Zi Wang ◽  
Zhi Wei Zhu ◽  
Wei Cao ◽  
Hong De Zhou ◽  
Yu Wu ◽  
...  

Electrochemical processing combined with the system of microalgaeChlorella vulgariswas used to treat the synthetic organic wastewater in this paper. The effect of wastewater concentration on the biomass growth and nutrients removal was investigated. Three levels of the wastewater concentrations were ranked as Low, Mid and High, respectively. After 2 h of electrolysis pretreatment and 10 d of microalgae cultivation, TOC, NH4-N, and TP concentrations in the group Low were reduced by 83.7%, 99.3% and 95.0%, respectively. TheChlorella vulgarisin the groups Mid and High without electrolysis pretreatment did not survive longer than 24 h, whereas it grown well in the wastewater pretreated by electrolysis. The dry weight (DW) ofChlorella vulgarisin the group Low with electrolysis pretreatment was increased from 0.048 g/l to 1.087 g/l by 10 d cultivation. Results indicate that electrolysis pretreatment for wastewater can provide appropriate conditions for the subsequent biological treatment and efficiently promote the biomass growth ofChlorella vulgaris.


2015 ◽  
Vol 1113 ◽  
pp. 364-369 ◽  
Author(s):  
Tamilarasi B. Tamil Selvam ◽  
Rajkumar Renganathan ◽  
Mohd Sobri Takriff

The study examines the efficiency of nutrients removal by a locally isolatedmicroalgae strain from Palm Oil Mill Effluent (POME) treatment pond, Characium sp. Theexperiment was conducted in laboratory conditions at room temperature for 20 days. Sampleswere taken at a two-day interval for dry weight, Chemical Oxygen Demand (COD), andnutrient removal analysis as well as carotenoid, protein and lipid content. The study showedthat the COD level of POME was reduced by 45.41%. Characium sp successfully removed90.35% of ammoniacal nitrogen, 86.9% of ammonia, 87% of ammonium and 88.6% of totalnitrogen content. This species was also found to remove up to 99.1% of phosphate contentand 99.5% of phosphorus. Characium sp produced 0.78 mg/L of carotenoid, 15.24 mg/L ofprotein and 18.43 mg/L of lipid by the end of the 20-day study period.


Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2660
Author(s):  
Marco Antonio Segovia Bifarini ◽  
Miha Žitnik ◽  
Tjaša Griessler Bulc ◽  
Aleksandra Krivograd Klemenčič

In this study, we examined a Chlorella vulgaris-based system as a potential solution to change liquid waste, such as blackwater, into valuable products for agriculture while protecting waters from pollution without technical demanding pre-treatment. To evaluate the possibility of nutrient removal and biomass production from raw blackwater, four blackwater dilutions were tested at lab-scale: 50%, 30%, 20%, and 10%. The results showed that even the less diluted raw blackwater was a suitable growth medium for microalgae C. vulgaris. As expected, the optimum conditions were observed in 10% blackwater with the highest growth rate (0.265 d−1) and a nutrient removal efficiency of 99.6% for ammonium and 33.7% for phosphate. However, the highest biomass productivity (5.581 mg chlorophyll-a L−1 d−1) and total biomass (332.82 mg dry weight L−1) were achieved in 50% blackwater together with the highest chemical oxygen demand removal (81%) as a result of the highest nutrient content and thus prolonged growth phase. The results suggested that the dilution factor of 0.5 followed by microalgae cultivation with a hydraulic retention time of 14 days could offer the highest biomass production for the potential use in agriculture and, in parallel, a way to treat raw blackwater from source-separation sanitation systems.


2017 ◽  
Vol 57 (3) ◽  
pp. 228-236 ◽  
Author(s):  
Zahra Fathi ◽  
Ramazan-Ali Khavari Nejad ◽  
Homa Mahmoodzadeh ◽  
Taher Nejad Satari

Abstract Carbon nanotubes act as regulators of plant germination and growth and are able to change the morphology and physiology of plant cells. The castor plant (Ricinus communis L.) belongs to the Euphorbiaceae family and is a very important medicinal plant. The aim of this study was to investigate the effect of 10 different concentrations of multi-walled carbon nanotubes (MWCNTs) (2, 5, 10, 20, 50, 75, 100, 125, 250 and 500 μg · ml−1) alongside the control under laboratory conditions on the germination and growth of castor seedlings. The results demonstrated that the maximum percentage of germination (96.7%) and relative germination percentage (100%) were found in the concentrations of 50 and 100 μg · ml−1, respectively, and the highest germination rate (53.3%) and the mean germination time (4.6 days) was seen in the concentration of 75 μg · ml−1. However, no statistically significant differences were found between the different concentrations in any of the germination factors. In the concentration of 100 μg · ml−1, there was a significant increase in the seedling vigor index I (400) when compared with the concentrations of 5 and 10 μg · ml−1. The maximum seedling vigor index II (11.3) was found in the concentration of 100 μg · ml−1 and was significantly different from the control and all applied concentrations. The length of radicle in the 100 and 125 μg · ml−1 had a significant increase when compared with the control and the concentrations of 10 and 50 μg · ml−1. The maximum seedling length (4.6 cm) was seen in the concentration of 100 μg · ml−1 where there was a significant increase with 10 μg · ml−1. Moreover, in the 100 μg · ml−1 concentration, the largest number of rootlets (8.6) was seen and when compared with the control and concentrations of 5, 10 and 50 μg · ml−1, there was a statistically significant increase. The maximum wet weight (0.3 g) and dry weight (0.1 g) of seedlings were obtained in the concentration of 100 μg · ml−1 and when compared with the control, there was a significant increase. It was found that in all factors related to the growth of seedlings, the concentrations of 10 and 50 MWCNTs had an inhibitory effect on the response index. The MWCNTs concentration of 100 μg · ml−1 was considered as the optimum concentration in the growth stage of castor seedlings.


2021 ◽  
Author(s):  
Katrin Weise ◽  
Thomas Kurth ◽  
Irina Politowski ◽  
Carola Winkelmann ◽  
Andreas Schäffer ◽  
...  

Abstract Although the development and application of nanomaterials is a growing industry, little data is available on the ecotoxicological effects on aquatic organisms. Therefore, we set up a workflow to address the potential uptake of weathered multi-walled carbon nanotubes (wMWCNTs) by a model organism, the pulmonary mudsnail Lymnaea stagnalis (L. stagnalis), which plays an important role in the food web. It represents a suitable organism for this approach because as a grazer it potentially ingests large amounts of sedimented wMWCNTs. As food source for L. stagnalis, benthic biofilm was investigated by the use of a transmission electron microscope (TEM), and a scanning electron microscope (SEM) after exposure with wMWCNTs. In addition, isotopic labeling was applied with 14C-wMWCNTs (0.1 mg/L) to quantify fate, behavior and enrichment of 14C-wMWCNTs in benthic biofilm and in L. stagnalis. Enrichment in benthic biofilm amounted to 529.0 µg wMWCNTs/g dry weight and in L. stagnalis to 79.6 µg wMWCNTs/g dry weight. A bioconcentration factor (BCF) for L. stagnalis was calculated (3,500 L/kg). We demonstrate the accumulation of wMWCNTs (10 mg/L) in the digestive tract of L. stagnalis in an effect study. Moreover, the physiological markers glycogen and triglycerides as indicators for the physiological state, as well as the RNA/DNA ratio as growth indicator were examined. No significant differences between exposed and control animals were analyzed for glycogen and triglycerides after 24 d of exposure, but a decreasing trend is recognizable for triglycerides. In contrast, the significant reduction in the RNA/DNA ratio of L. stagnalis indicated an inhibition of growth with a following recovery after depuration. The described workflow enables a comprehensive determination of the fate and the behavior of wMWCNTs in specifically and in general all kinds of CNT in the aquatic environment and therefore contributes to a holistic risk assessment of wMWCNTs.


Acta Naturae ◽  
2011 ◽  
Vol 3 (1) ◽  
pp. 99-106 ◽  
Author(s):  
E A Smirnova ◽  
A A Gusev ◽  
O N Zaitseva ◽  
E M Lazareva ◽  
G E Onishchenko ◽  
...  

2003 ◽  
Vol 772 ◽  
Author(s):  
T. Seeger ◽  
G. de la Fuente ◽  
W.K. Maser ◽  
A.M. Benito ◽  
A. Righi ◽  
...  

AbstractCarbon nanotubes (CNT) are interesting candidates for the reinforcement in robust composites and for conducting fillers in polymers due to their fascinating electronic and mechanical properties. For the first time, we report the incorporation of multi walled carbon nanotubes (MWNTs) into silica-glass surfaces by means of partial surface-melting caused by a continuous wave Nd:YAG laser. MWNTs were detected being well incorporated in the silica-surface. The composites are characterized using scanning electron microscopy (SEM) and Raman-spectroscopy. A model for the composite-formation is proposed based on heatabsorption by MWNTs and a partial melting of the silica-surface.


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