Effect of Ni Content Variation on the Synthesis of Nickel-Mobile Crystalline Material-41 (Ni-MCM-41) for Methylene Blue Adsorption L. O. Ahmad, H. Hidayat, A. Zaeni, F. Muhamad International Journal of Acta Material Vol. 1 No. 2 2025 DOI 10.62749/ijactmat.v1i2.13