Siregar, Patimah Mega Syah Bahar Nur, et al. “Mg/Al-CH,/Ni/Al-CH/and/Zn/Al-CH,/As/Adsorbents/for/Congo/Red/Removal/in/Aqueous/Solution”. Communications in Science and Technology, vol. 6, no. 2, Dec. 2021, pp. 74-79, doi:10.21924/cst.6.2.2021.547.