Adsorptive removal of dye from textile wastewater employing Moringa oleifera leaves biochar as a natural biosorbent

Moringa oleifera biochar (MOB) was used to extract dyes from textile wastewater and methylene blue (MB)-infused synthetic aqueous solution. Different process parameters, such as pH, agitation speed, the dosage of adsorption, and time of interaction, have been investigated by batch experiments. Up to 99% of dye removal was achieved for textile wastewater and 98% for MB-infused aqueous solution under optimum operating conditions. The optimum dosage, contact period, and agitation speed were 6 g/L, 15 min, and 200 rpm, respectively. An improvement in adsorption rates at higher pH was observed. The dye removal rate for pH less than 6 was insignificant, and the maximum removal was observed at a pH range of 10 to 12. Batch experiments showed that the Freundlich isotherm model better described the adsorption process for textile wastewater and MB dye solution. Lagergren's pseudo-second-order kinetic model fitted relatively well (R-2 =0.99) over the observed contact period (5-60 min) compared to the pseudo-first-order kinetic model. Besides dye removal, MOB showed a significant reduction capacity of BOD5, COD, and EC values for textile wastewater treatment. The results indicate that MOB adsorbent has a high potential for being used as a low-cost adsorbent to treat textile wastewater in south-Asian countries since it is abundantly available in the subcontinent.

Automated summary

The study found that Moringa oleifera biochar (MOB) can effectively remove dyes from textile wastewater and methylene blue-infused aqueous solutions. The dye removal rates reached 99% for textile wastewater and 98% for the MB-infused solution under optimal conditions. Additionally, MOB also showed a significant reduction capacity for BOD5, COD, and EC values in textile wastewater treatment.