The aim of the study was to examine the spatial and temporal variations in the physicochemical parameters of seagrass meadows of the Gulf of Mannar, South India using multivariate statistical techniques, namely, cluster analysis (CA) and principal component analysis (PCA), to explore the relationship. There were clear spatial and temporal variations in physicochemical variables of the seagrass meadow of the Gulf of Mannar, but such changes were subjected to seasonal variations especially during monsoon and post-monsoon seasons. The multivariate statistical techniques, viz., CA and PCA helped in the discrimination of islands according to the physicochemical parameters of the seagrass meadows. It was inferred that electrical conductivity, nitrate, particulate organic carbon, and phosphate strongly determined the discrimination of 19 islands, respectively, upon physicochemical characteristics of their seagrass meadows. These results highlight the important role of seagrasses in the Gulf of Mannar Marine Biosphere Reserve. 相似文献
Bioleaching is considered an eco-friendly technique for leaching metals from spent hydroprocessing catalysts; however, the low bioleaching yield of some valuable metals (Mo and V) is a severe bottleneck to its successful implementation. The present study reported the potential of an integrated bioleaching-chemical oxidation process in improved leaching of valuable metals (Mo and V) from refinery spent hydroprocessing catalysts. The first stage bioleaching of a spent catalyst (coked/decoked) was conducted using sulfur-oxidizing microbes. The results suggested that after 72 h of bioleaching, 85.7% Ni, 86.9% V, and 72.1% Mo were leached out from the coked spent catalyst. Bioleaching yield in decoked spent catalyst was relatively lower (86.8% Ni, 79.8% V, and 59.8% Mo). The low bioleaching yield in the decoked spent catalyst was attributed to metals’ presence in stable fractions (residual + oxidizable). After first stage bioleaching, the integration of a second stage chemical oxidation process (1 M H2O2) drastically improved the leaching of Ni, Mo, and V (94.2–100%) from the coked spent catalyst. The improvement was attributed to the high redox potential (1.77 V) of the H2O2, which led to the transformation of low-valence metal sulfides into high-valence metallic ions more conducive to acidic bioleaching. In the decoked spent catalyst, the increment in the leaching yield after second stage chemical oxidation was marginal (<5%). The results suggested that the integrated bioleaching-chemical oxidation process is an effective method for the complete leaching of valuable metals from the coked spent catalyst.
Journal of Material Cycles and Waste Management - Recycling of mixed waste, including plastic and rubber, by the blending process is one of the promising sustainable routes. In this paper, the... 相似文献
A number of mitigation techniques exist to reduce the emissions of pollutant gases and greenhouse gases(GHGs) from anaerobic storage of livestock manure. Nanoparticle(NP)application is a promising mitigating treatment option for pollutant gases, but limited research is available on the mode of NP application and their effectiveness in gaseous emission reduction. In this study, zinc silica nanogel(ZnSNL), copper silica nanogel(CuSNL), and N-acetyl cysteine(NACL) coated zinc oxide quantum dot(Qdot) NPs were compared to a control lacking NPs. All three NPs tested significantly reduced gas production and concentrations compared to non-treated manure. Overall, cumulative gas volumes were reduced by 92.73%–95.83%, and concentrations reduced by 48.98%–99.75% for H_2S, and 20.24%–99.82% for GHGs. Thus, application of NPs is a potential treatment option for mitigating pollutant and GHG emissions from anaerobically stored manure. 相似文献
Environmental Science and Pollution Research - Demand for fresh water increases day by day. Solar desalination is one of the promising technologies to meet this demand in an economical fashion... 相似文献