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Water Treatment as the regulatory limitations regarding the use of bio-sourced chemicals. Finally, we will discuss the experience gained from transitioning from a polyacrylate-based antiscalant treatment to ODYLIFE in a Cooling Tower( CT).
II. Materials and methods II. 1. Characterization of the extract Characterization of plant extracts is carried out using two methods:( i) quantification of dry residues;( ii) quantification of an active molecule referred to as the“ tracer active”. The measurement of dry residues is performed by evaporating 2 mL of filtered plant extract in an aluminum dish with a diameter of 7 cm placed on a hot plate set at 130 ° C. Quantification of the“ tracer active” is carried out by UV-visible spectrophotometry. The optimized method allows quantification over a range of 0 to 100 mg / L with a precision of +/- 3 mg / L.
II. 2. Extraction of the active material and yield The eco-extraction method of plant dry matter( DM) developed was compared to conventional protocols for plant material extraction in a previous publication [ 5 ]. In the context of a single-step extraction, the yield can be calculated using the formula below.
yield �
�C��
V �extract� m�plant�
With [ C ] being the mass concentration of extracted molecules, V( extract) the total volume of the extract, and m( plant) the dry mass of the added plant material. In the context of this study, extractions in multiple steps( by exhaustion or by enrichment) are performed( see Section III. 2.1 Extraction). The yield at step n can then be calculated as follows.
yield n
�
��C� ��C�
��V
�extract� n n� m�plant�
1 n
With [ C ] n representing the mass concentration of extracted molecules at step n and [ C ] n-1 representing that at step n-1, V( extract) n the total volume of the extract at the end of step n, and m( plant) n the mass of plant material added at step n.
II. 3. Characterization of the efficiency of a scale inhibitor The efficiency measurement is conducted using chronoamperometry [ 1,6 ]. The experiments are conducted in a three-electrode cell. The reference electrode is a saturated calomel electrode( SCE), and the counter electrode is a platinum grid. The working electrode is a rotating disk electrode( RDE) with a carbon steel tip with a specific surface area of 1 cm ². The rotation speed of the RDE is 1,000 rpm, and the temperature is maintained at 35 ° C. The electrolyte is osmosed water containing 0.500 g / L of CaSO4, 2 H2O; 0.60 g / L of MgSO4, 7 H2O; 0.420 g / L of NaHCO3. This
n
Figure 2: Calibration curve for the quantification method of the“ Active tracer” contained in ODYLIFE.
results in a total hardness( TH) of 315 ° f and a total alkalinity( TAC) of 25.0 ° f. The measurement is performed using a Biologic SP-150 potentiostat, and the control and processing software is EC-Lab. The measurement is conducted over 120 minutes. The efficiency is calculated as follows:
�
Efficiency %
�
Time of scaling without inhibitor �Time of scaling with inhibitor
�
120min �Time of scaling without inhibitor
III. Technological barriers: results and discussion III. 1. Quantification Traditional methods for quantifying active principles mainly rely on measuring dry residues( DR) or on chemical oxygen demand( COD) measurement. In the absence of a purification phase, the extraction of plant materials leads to obtaining an extract containing a large number of molecules( proteins, fats, mineral salts, sugars, phenolic compounds, terpene compounds, etc.), not all of which necessarily contribute to scale inhibition [ 7 ]. In this context, ODYSSEE Environnement has developed a protocol to quantify the so-called“ Tracer Active” in each plant extract. Figure 1 depicts the inhibitory efficacy of 3 antiscalant products as a function of dry residue concentration( a) or of a“ Tracer Active” principle( b). Figure 1a shows that the efficacy of sources P and B reaches 100 % at 5 mg DR / L( Dry Residue per Liter), while source N reaches 100 % at most at 50 mg RS / L. Figure 1b indicates that, regardless of the source, efficacy is achieved for at most 4 mg / L of“ Active tracer”( or equivalent concentration in petro-sourced active molecule). The efficacy of a source is therefore correlated with its concentration of“ Active tracers”. Figure 2 represents the calibration curve of the quantification method of the“ Active tracer”, according to the method optimized by ODYSSEE Environnement.
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