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70&nbsp;±&nbsp;0.06&nbsp;mg GAE g-1 DW), TFC (8.19&nbsp;±&nbsp;0.01&nbsp;mg QUE g-1 DW), antioxidant activities (73.88&nbsp;±&nbsp;0.47%) and maximum PAL activity (1.25&nbsp;±&nbsp;0.08&nbsp;mM&nbsp;cm g-1 FW) were detected in plants grown on MS media fortified with 250&nbsp;μg&nbsp;ml-1 MWCNTs. The results reveal that MWCNTs in low doses (250&nbsp;μg&nbsp;ml-1) can encourage the production of biomass, elicit more SM from seedlings and enhance the biosynthesis of antioxidants. TEM images showed that MWCNTs could cross the plant cell wall and enter the cellular cytoplasm. Sulfidized nanoscale zerovalent iron (S-nZVI) is an Fe-based reactant widely studied for its potential use for groundwater remediation. S-nZVI reactivity has been widely investigated testing various contaminants in various water matrices, but studies on S-nZVI corrosion behaviour and reactivity upon exposure to complex groundwater chemistries are limited. Here, we show that anoxic aging of S-nZVI for 7 days in the absence and presence of key groundwater solutes (i.e., Cl-, SO42-, Mg2+, Ca2+, HCO3-, CO32-, NO3-, or HPO42-) impacts Fe0 corrosion extent, corrosion product and reduction rates with trichloroethene (TCE). White rust was the dominant corrosion product in ultrapure water and in SO42-, Cl-, Mg2+ or Ca2+ solutions; green rust and/or chukanovite formed in HCO3- and CO32- solutions; magnetite, formed in NO3- solutions and vivianite in HPO42- solutions. The aged S-nZVI materials expectedly showed lower reactivities with TCE compared to unaged S-nZVI, with reaction rates mainly controlled by ion concentration, Fe0 corrosion extent, type(s) of corrosion product, and solution pH. Comparison of these results to observations in two types of groundwaters, one from a carbonate-rich aquifer and one from a marine intruded aquifer, showed that S-nZVI corrosion products are likely controlled by the dominant GW solutes, while reactivity with TCE is generally lower than expected, due to the multitude of ion effects. Overall, these results highlight that S-nZVI corrosion behaviour in GW can be manifold, with varied impact on its reactivity. Thus, testing of S-nZVI stability and reactivity under expected field conditions is key to understand its longevity in remediation applications. Presence of heavy metals in the wastewater sludge has greatly hindered sludge land application. Bioleaching has been developed for heavy metal removal from sludge. [https://www.selleckchem.com/products/lonafarnib-sch66336.html check details] The pH of the sludge is declined by microorganisms with S or FeS as energy source. Sludge considered to be used in land is mainly due to its fertilizer values as it contains nitrogen, phosphorus, and potassium. Therefore, it is important to understand how the bioleaching would impact on sludge characterization. In addition, pathogens are great threat to human health. The ability of pathogen elimination of bioleaching is highly concerned. In this review, the major heavy metals in the sludge are summarized. The change of nitrogen, phosphorus, and potassium after bioleaching is stated. The pathogen elimination due to bioleaching has been discussed. The work has provided an insight of research need in sludge bioleaching with the aim of residual sludge land application. Lanthanum-modified bentonite (LMB, commercially called Phoslock®) has been widely applied in freshwater systems to manage eutrophication. Little is known, however, about its behaviour and efficiency in binding filterable reactive phosphorus (FRP) in saline environments. We assessed if LMB would adsorb phosphate over a range of salinities (0-32 ppth) comparing the behaviour in seawater salts and equivalent concentrations of NaCl. Lanthanum release from the bentonite matrix was measured and the La species prevailing in saline environments were evaluated through chemical equilibrium modelling. We demonstrated that LMB was able to adsorb FRP in all the salinities tested. Filterable lanthanum (FLa) concentrations were similarly low (2000 times greater in equivalent NaCl salinities. Mineralogical analysis indicates that La present in the clay interlayer was (partially) replaced by Na/Ca/Mg present in the seawater and a possible secondary P-reactive phase was formed, such as kozoite (LaCO3OH) or lanthanite (La2(CO3)3·8H2O) that may be physically dissociated from the LMB. Geochemical modelling also indicates that most FLa dissociated from LMB would be precipitated as a carbonate complex. In light of the identification of reactive intermediate phases, further studies including ecotoxicologial assays are required to assess any deleterious effects from the application of LMB to saline waters. In this study, the effect of ball milling on pyrite (FeS2) promoting arsenic (As) removal by zero-valent iron (Fe0) was investigated. The influences of different mass ratios of ball-milled FeS2/Fe0, the dosage of ball-milled FeS2/Fe0 used and initial pH value were evaluated by batch experiments. The results showed that the ball-milled FeS2/Fe0 system had a higher total As removal efficiency than the mixed FeS2-Fe0 system, ball-milled FeS2 and ball-milled Fe0 systems in equal mass. Higher As removal efficiency in ball-milled FeS2/Fe0 system was primarily related to the accelerated corrosion of Fe0, which was supported by the determination of total Fe2+ release and electrochemical experiments. SEM-EDS and XPS characterizations revealed that there were iron sulfides (Fe(II)-S and Fe(III)-S) produced on the surface of Fe0 in ball-milled FeS2/Fe0, which could facilitate the electron transfer of Fe0 and enhanced the corrosion of it. BET test also indicated that ball-milled FeS2/Fe0 possessed a higher specific surface area than ball-milled Fe0. In addition, the results also showed the optimum mass ratio of FeS2 and Fe0 in ball-milled FeS2/Fe0 to remove As ([As(III)]&nbsp;=&nbsp;2&nbsp;mg/L) was 11, and the optimum dosage was 0.5&nbsp;g/L, thereby indicating the optimal AsFe0 molar ratio was about 1168. And the removal rate of As by ball-milled FeS2/Fe0 was faster in acidic condition than that in alkaline condition. These findings suggest that Fe0-based arsenic removal efficiency can be enhanced by ball-milling with FeS2, making it more feasible for remediation of arsenic-polluted water.