Magnesium Sample Clauses
Magnesium. Magnesium separation from matrix elements (mainly Ca) was performed using the protocol defined by Teng et al. (2007), in which ~15 µg of Mg were evaporated to dryness and re-dissolved in 2 ml 1 N HNO3 solution. Later, samples were loaded onto Bio-Rad poly prop 10 ml columns containing AG50W-X12 resin. Mg isotopes were measured with a Thermo-▇▇▇▇▇▇▇▇ ‘Neptune’ Multi Collector Inductively Coupled Plasma Mass Spectrometer (MC-ICP- MS) at GET (Toulouse, France). All solutions were prepared in 0.32 M HNO3 and were introduced into the Ar Plasma using a standard spray chamber. Instrumental mass fractionation effects were corrected using sample-standard bracketing, and all data are presented in delta notation with respect to DSM3 international reference material (Galy et al., 2001): ( δxMg (‰) = ( xMg / 24Mg)sample ( x Mg / 24Mg)DSM 3 – 1) *1000 The reproducibility of δ26Mg analyses was typically <0.07 ‰ as confirmed by replicate analyses of three international Mg reference standards (DSM-3, CAM-1 and OUMg).
Magnesium. Magnesium values measured in the influent AMD were highly consistent over the 377 day experiment with values averaging near 210±16 mg/L Mg2+. Reactor 1 (LS) magnesium concentration values were similar to those of influent, averaging 238±20mg/L Mg2+ for the duration of the experiment (Figure 24). However, on sporadic occasions noticeable increases in magnesium were documented in the effluent of reactor 1 (LS). Within the effluent of the biologic reactors high magnesium concentrations were determined during the initial two weeks of operation reaching values up to 461mg/L Mg2+. In contrast to trends in calcium concentrations, after the initial two weeks magnesium values in the bioreactor effluents (R2-R6) were observed as being similar to that of the limestone effluent (R1). From 9/26/2012 to 9/5/2013 magnesium concentrations averaged 237±19, 236±27, 233±22, 230±27, 237±27 and 231±27 for R1, R2, R3, R4, R5, and R6, respectively. Therefore, from late September 2012 to early September 2013 on average all reactors (R1-R6) increased magnesium concentrations of the influent AMD by roughly 26mg/L Mg2+. Figure 24 Magnesium concentrations (mg/L Mg2+) measured in the AMD influent and effluent samples of each reactor (R1-R6) during each sampling event.