scholarly journals Remediation of Anthracene-Contaminated Soil with Sophorolipids-SDBS-Na2SiO3 and Treatment of Eluting Wastewater

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2188
Author(s):  
Wei Li ◽  
Xiaofeng Wang ◽  
Lixiang Shi ◽  
Xianyuan Du ◽  
Zhansheng Wang

The soil pollution of polycyclic aromatic hydrocarbons (PAHs) is serious in China, which not only affects the living and growing environment of plants and animals but also has a great impact on people’s health. The use of hydrophobic organic compounds to make use of surfactant ectopic elution processing is more convenient and cheaper as a repair scheme and can effectively wash out the polycyclic aromatic hydrocarbons in the soil. Therefore, we mixed sophorolipids:sodium dodecylbenzene sulfonate (SDBS):Na2SiO3 according to the mass ratio of 1:15:150. We explored the influencing factors of high and low concentrations of PAH-contaminated soil using a single factor test and four factors at a two-level factorial design. Then, the elution wastewater was treated by ultrasonic oxidation technology and the alkali-activated sodium persulfate technology. The results showed that: (1) In the single factor test, when the elution time is 8 h, the concentration of the compounded surfactant is 1200 mg/L, the particle size is 60 mesh, the concentration of NaCl is 100 mmol/L, and the concentration of KCl is 50 mmol/L, and the effect of the PAH-contaminated soil eluted by the composite surfactant is the best. Externally added NaCl and KCl salt ions have a more obvious promotion effect on the polycyclic aromatic hydrocarbon-contaminated soil; (2) in the interaction experiment, single factor B (elution time) and D (NaCl concentration) have a significant main effect. There is also a certain interaction between factor A (concentration agent concentration) and factor D, factor B, and factor C (KCl concentration); (3) the treatment of anthracene in the eluate by ultrasonic completely mineralizes the organic pollutants by the thermal and chemical effects produced by the ultrasonic cavitation phenomenon, so that the organic pollutants in the eluate are oxidized and degraded into simple environmentally friendly small molecular substances. When the optimal ultrasonic time is 60 min and the ratio of oxidant to activator is 1:2, the removal rate of contaminants in the eluent can reach 63.7%. At the same time, the turbidity of the eluent is significantly lower than that of the liquid after centrifugal separation, indicating that oxidants can not only remove the pollutants in elution water but also remove the residual soil particulate matter; and (4) by comparing the infrared spectrum of the eluted waste liquid before and after oxidation, it can be seen that during the oxidation process, the inner part of eluent waste liquid underwent a ring-opening reaction, and the ring-opening reaction also occurred in the part of the cyclic ester group of the surfactant, which changed from a ring to non-ring.

Author(s):  
C. Fawole ◽  
S. J. Salami ◽  
D. A. Dashak ◽  
H. A. Chimezie-Nwosu

The ex situ study of vermiextraction of Acenaphthylene (AcPY), Benzo(e)pyrene (BeP) and Benzo(ghi)perylene (BP) form constructed vermiculture containing petroleum contaminated soil (8.00±0.01, 9.80±0.00 and 5.02±0.00 mg/kg respectively) and vermiaccumulation (AcPY, 1.05±0.00, BeP, 2.01±0.00 and BP, 1.73±0.00 mg/kg) by Esenia fetida squirms with mean vermiremoval efficiency of 100% while vermiconversions were AcPY, 86.88, BeP, 79.49 and BP, 65.54%. The identification and quantification of the 3 polycyclic aromatic hydrocarbons (3PAHs) were performed by GS/MD in accordance with analytical procedure of US. EPA 8270; 625. The bioengineered approach by E. fetida squirms in the vermiculture proved effective to detoxify and remove the persistent organic pollutants of the 3PAHs. The ex situ study of vermiextraction of Acenaphthylene (AcPY), Benzo(e)pyrene (BeP) and Benzo(ghi)perylene (BP) form constructed vermiculture containing petroleum contaminated soil (8.00±0.01, 9.80±0.00 and 5.02±0.00 mg/kg respectively) and vermiaccumulation (AcPY, 1.05±0.00, BeP, 2.01±0.00 and BP, 1.73±0.00 mg/kg) by Esenia fetida squirms with mean vermiremoval efficiency of 100% while vermiconversions were AcPY, 86.88, BeP, 79.49 and BP, 65.54%. The identification and quantification of the 3 polycyclic aromatic hydrocarbons (3PAHs) were performed by GS/MD in accordance with analytical procedure of US. EPA 8270; 625. The bioengineered approach by E. fetida squirms in the vermiculture proved effective to detoxify and remove the persistent organic pollutants of the 3PAHs.


2021 ◽  
Vol 12 ◽  
Author(s):  
Xinwei Ren ◽  
Jingchun Tang ◽  
Lan Wang ◽  
Hongwen Sun

Microplastics (MPs) have been attracting wide attention. Biochar (BC) application could improve the soil quality in the contaminated soil. Currently, most studies focused on the effect of MPs or BC on the soil properties and microbial community, while they neglected the combined effects. This study investigated the combined effects of BC or ball-milled BC (BM) and polyethylene plastic fragments (PEPFs) and degradable plastic fragments (DPFs) on the removal of polycyclic aromatic hydrocarbons (PAHs) and phthalate esters (PAEs) from the PAH-contaminated soil and the potential microbial ecological mechanisms. The results showed that BC or BM combined with PEPF could accelerate the removal of PAHs and PAEs. PEPF combined with BM had the most significant effect on the removal of PAHs. Our results indicating two potential possible reasons contribute to increasing the removal of organic pollutants: (1) the high sorption rate on the PEPF and BC and (2) the increased PAH-degrader or PAE-degrader abundance for the removal of organic pollutants.


2014 ◽  
Vol 665 ◽  
pp. 534-537
Author(s):  
Hong Wang ◽  
Hai Bo Li ◽  
Xin Wang ◽  
Ji Fu Ma

Degradation of polycyclic aromatic hydrocarbons (PAHs) and microbial quantity were investigated in aged PAHs-contaminated soil in a pot experiment with regrass and alfalfa. After 60 days germination the concentration of total PAHs in soil decreased by 37.57% and 38.41% with the treatment of ryegrass-microbe agent and alfalfa-microbe agent. The processes of ryegrass and alfalfa were 18.72% and 19.34%. The root system promoted the quantity of microbe and the microbial agent was benefit for the PAHs degrading microbe. And there was significant positive correlation between the number of PAHs degrading microorganisms and the removal rate of PAHs in the soil.


2019 ◽  
Author(s):  
Temidayo O Elufisan ◽  
Isabel C Rodríguez-Luna ◽  
Omotayo O Oyedara ◽  
Alejandro Sánchez-Varela ◽  
Armando Hernandez Mendoza ◽  
...  

Background: Stenotrophomonas are ubiquitous gram-negative bacteria which survive in a wide range of environments. They can use many substances for their growth and are known to be intrinsically resistant to many antimicrobial agents. They have been tested for biotechnological applications, bioremediation and antimicrobial agents because of their recalcitrant nature to many toxic compounds. Method. Stenotrophomonas sp. Pemsol was isolated from a crude oil contaminated soil. The capability of this isolate to tolerate and degrade polycyclic aromatic hydrocarbons (PAHs) (anthracene, anthraquinone, biphenyl, naphthalene, phenanthrene, phenanthridine and xylene) was evaluated on Bush Nell Hass medium containing PAHs as the unique carbon sources. The metabolites formed after 30-day degradation of naphthalene by Pemsol were analyzed using Fourier Transform Infra-red Spectroscopic (FTIR), Ultra-Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS) and Gas Chromatography-Mass Spectrometry (GC-MS). Results. Complete degradation of naphthalene at a concentration of 1 mg/mL was obtained and a newly formed catechol peak obtained from the UPLC-MS and GC-MS confirmed the degradation. The strain Pemsol lacked the ability to produce biosurfactant so that it cannot bio-emulsify PAHs. The whole genome analysis of Stenotrophomonas sp. Pemsol revealed a wealth of genes for hydrocarbon utilization and interaction with the environment and the presence of 147 genes associated with the degradation of PAHs, some of which are strain-specific on the genomic islands. Few genes are associated with bio-emulsification indicated that Pemsol without biosurfactant production has a genetic basis. This is the first report of the complete genome analysis sequence of a PAH-degrading Stenotrophomonas. Stenotrophomonas sp. Pemsol possesses features that makes it a good bacterium for genetic engineering and will therefore be a good tool for the remediation of crude oil or PAH-contaminated soil.


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