Preliminary Studies of Methylene Blue Remotion from Aqueous Solutions by Ocimum basilicum

The continuous expansion in the textile industry results in high loads of coloured wastewaters that heavily pollute the limited freshwater sources. Therefore, a wide array of treatment methods has been used to remediate water/wastewater from dyes. One common practice is the use of plants to degrade, absorb, metabolise, and detoxify different types of pollutants, including dyes. This study employs sweet basil (Ocimum basilicum) as a phytoremediation model herb to remove different concentrations (5–25 mg/L) of methylene blue (MB) dye from synthetic water, taking into account the effects of the MB dye concentration (5–25 mg/L) and contact time (up to 10 days). The results showed that the ability of Ocimum basilicum to absorb MB dye decreased with the increase of the MB dye concentration and increased with the increase of the contact time. The best removal of the MB dye was 93% when the concentration of the MB dye was 25 mg/L and the contact time was 10 days. Additionally, it was noticed that the relative growth rate (RGR) of the herbs was adversely influenced by increasing MB dye concentrations and that the best RGR value was 2.2 g/day when the MB dye concentration was 5 mg/L.

Self-assembly of soybean peroxidase nanohybrid for activity enhancement and dye decolorization: experimental and computational studies

The soybean peroxidase (SBP) mediated nanohybrid [SBP-Cu3(PO4)2·3H2O] synthesis was carried out in the present study. The scanning electron microscopy (SEM) analysis showed a characteristic flower-like hierarchical structure of the SBP-nanohybrid. The mechanism of SBP-nanohybrid formation was elucidated using computational approaches. The predicted Cu2+ binding sites followed by molecular docking studies showed the two lowest energy (-4.4 kcal/mol and -3.56 kcal/mol) Cu2+ binding sites. These two binding sites are located at the opposite position and might be involved in the formation of SBP-nanohybrid assemblies. Further, these sites are different than the catalytic active site pocket of SBP, and may facilitate more substrate catalysis. Obtained computational results were confirmed by in-vitro guaiacol oxidations studies using SBP-nanohybrid. The effect of various parameters on SBP-nanohybrid activity was studied. The pH 7.2 was found optimum for SBP-nanohybrid activity. The enzyme activity increased with an increase in temperature up to 50 °C temperature and then decreased with an increase in temperature. Around ∼138% enhanced activity was recorded using SBP-nanohybrid compared to crude SBP. Also, the SBP-nanohybrid showed around 95% decolorization of methylene blue (MB) in 1 h and the MB degradation was confirmed by high-pressure liquid chromatography analysis (HPLC).Communicated by Ramaswamy H. Sarma.

Study of the Characteristics of Two Immobilized Microbial Materials in Degradation and Evolution of Petroleum Hydrocarbon

To enhance the degradation efficiency of oily wastewater, polyacrylamide (PAM)-sodium alginate (SA) and poly(vinyl alcohol) (PVA)-sodium alginate (SA) were mixed and used as spherical supporting materials for the immobilization of microbials, which were employed as a platform to study the degradation of total petroleum hydrocarbons (TPHs) in the oily wastewater. The degradation and evolution of normal paraffin (n-paraffin) series have been studied by determining the crude oil group composition of the residual oils by the gas chromatography-mass spectrometry (GC-MS) analysis. The results show that the half-lives of the PAM-SA-immobilized microorganisms are 6.21 days, which is 2.11 days less than that of PVA-SA, indicating that more nutrients are provided by PAM-SA for microbial growth, which can accelerate the degradation of TPHs. As can be seen from the GC-MS analysis, the main peak carbons of the n-paraffin series are moved backward after 14 days of degradation, implying the degrading advantage of n-paraffin with low carbon numbers. The ∑C21^-/∑C22⁺ value of PAM-SA was measured to be 0.749, which is greater than that of PVA-SA (0.051), indicating that PAM-SA has a superior ability to degrade normal paraffins with high carbon numbers. After 14 days of degradation, an odd-even predominance (OEP) (the mass ratio of normal alkanes of odd carbon/even carbon) value of 1.075 for PAM-SA was obtained, which is slightly larger than that of PVA-SA (0.967), indicating a better degradation performance of PAM-SA, especially for the degradation of the even-carbon normal paraffins with high carbon numbers. The Pr/Ph of PAM-SA is 0.938, which is also greater than that of PVA-SA (0.844), indicating that the ability of PAM-SA for the degradation of isoprenoids is superior to that of PVA-SA under the immobilized conditions. Based on these results, in terms of immobilization of microorganisms, PAM-SA, instead of PVA-SA, is more advantageous for the degradation of TPH in the oily wastewater.

Scale-up of removal process using a remediating-bacterium isolated from marine coastal sediment

Nowadays, a wide variety of pollutants are discharged to different water sources and become water contaminants.

Enhanced decolorization of aqueous dye solutions by a high quality copolymer flocculant

A high quality copolymer flocculant (CATCS) with a high positive charge and unique strong bridging function is reported for the enhanced decolorization of dye solutions.