**2.2. Materials**

All reagents in this work were of analytical grade and used as received without further purification. NaOH (98%) was used as the initiator, which was obtained from Sigma Aldrich (French). The maghnite-Na+ (MMT-Na+ ) used in this work came from a quarry located in Maghnia (North West of Algeria) and was supplied by the company "ENOF" (Algerian manufacture specialized in the production of nonferric products and useful substances). The chemical composition, structure of the MMT-Na+ and comparison with American and French MMT were shown in (**Tables 1** and **2** and **Figure 1**). The cation exchange capacity (CEC) and

**Scheme 1.** Experimental equipment of microwave irradiation for synthesis of anionic polyacrylamide (APAm).

surface area of the clay was found to be 84 mEq (100 g−<sup>1</sup> ) of dried clay and 786 m2 g−<sup>1</sup> respectively, and its X-ray diffraction (XRD) analysis shows that the interlayer spacing of MMT-Na<sup>+</sup> is 1.29 nm [26].
