Green synthesis of magnetically separable and reusable Fe_(3)O_(4)/Cdots nanocomposites photocatalyst utilizing Moringa oleifera extract and watermelon peel for rapid dye degradation

This study focused on green-synthesized magnetite/carbon dots nanocomposites(GS-Fe_(3)O_(4)/Cdots)utilizing Moringa oleifera leaf extract and watermelon peel waste for rapid degradation of methylene blue(MB)dye.Co-precipitation and hydrothermal method were used to synthesize GS-Fe_(3)O_(4) and Cdots,respectively.In addition,the sonication method was used to link Cdots on Fe_(3)O_(4) surface.X-ray diffraction spectrum of GS-Fe_(3)O_(4)/Cdots inform the cubic inverse spinel and has crystallite size in the range of 10.1-7.2 nm.The crystallite size also decreased with the increase of Cdots concentration.The transmission electron microscope showed the most uniform size of nanocomposites at around 13.4 nm.The functional group of Fe-O was detected on the nanocomposites,proof that Fe_(3)O_(4) still exists after fabrication.The presence of C=C,C-O,and C-O-C also indicates the existence of Cdots on the surface of Fe_(3)O_(4).The addition of Cdots affected the saturation magnetization and coercivity value in the range of 29.2-38.3 emu/g and 59-65 Oe,respectively,which showed a good magnetic properties.As an organic dye,MB was used for a photocatalytic process under UV irradiation.The degradation efficiency was raised to 98% for 30 min photocatalytic process.The magnetically separable capability makes nanocomposites could be recycled and reused three times with high degradation.Furthermore,GS-Fe_(3)O_(4)/Cdots potential as a low-cost and environmentally friendly reusable photocatalyst for rapid wastewater degradation.