[1] Univ Malakand, Ctr Computat Mat Sci, Chakdara, Pakistan
[2] Univ Malakand, Dept Chem, Chakdara, Pakistan
[3] Gomal Univ, Dept Phys, Dera Ismail Khan, Pakistan
[4] South China Univ Technol, Sch Environm & Energy, Guangdong Prov Key Lab Solid Wastes Pollut Contro, Guangzhou 510006, Guangdong, Peoples R China