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Effect of contact time on MB and SHW adsorption (C o , MB 10 mg/L, C o,SHW 0.054 AB (absorbance); biochar 0.05 g; pH MB 6.19, pH SHW 6.09; temperature 25 °C).

Effect of contact time on MB and SHW adsorption (C o , MB 10 mg/L, C o,SHW 0.054 AB (absorbance); biochar 0.05 g; pH MB 6.19, pH SHW 6.09; temperature 25 °C).

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A comparative study on the discoloration of methylene blue (MB)and slaughter house waste water (SHW)using maize cob biochar produced by a laboratory constructed burning chamber was undertaken in this study. Contact time, pH, initial MB and SHW concentrations, mass of biochar and temperature were used to evaluate the efficiency of the biochar in dis...

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... discoloration of MB and SHW on biochar was studied from 0-60 min and the results are presented in Fig. 3 . The discoloration of both MB and SHW occurred in three phases; very fast in the first five minutes attaining discoloration of 55% for MB and 94% for SHW. This was followed by slowdown and attaining equilibrium in 15 min for the two pollutants (100% discoloration for SHW and 64% for MB). While SHW discoloration showed a steady ...

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... A global estimate of about 1.5 millionTons/year phosphates is discharged in to freshwater systems from both diffuse and point sources annually with the domestic sector contributing 54%, followed by agriculture (38%) and industry (8%) [2]. Slaughter house activity also significantly pollutes water sources as 29% of the total freshwater used in the agricultural sector worldwide are consumed by the meat processing industry alone [3]. Tanning involves the transformation of animal hides into leather that can be used to make handbags, shoes, belts, etc [4]. ...
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... However, recent studies worldwide show an evolving trend in the use of adsorption because of its ability to be operated at low cost with almost no energy consumption. Adsorption also has the potential to eliminate all types of pollutants at every concentration [6]. Of particular importance is the use of local materials and wastes as adsorbent in adsorption. ...
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... Among the food wastes being generated around the globe, the waste due to orange and banana peels occupies a major portion. Researchers have studied the application of biochars derived from different biomaterials for the removal of methylene blue (MB) dye (Chen et al. 2019;Jawad et al. 2019;Park et al. 2019;Tsamo et al. 2019). Biomass of orange and banana biomass as well as their derived biochars have also been used for the adsorption of MB dye (Dai et al. 2018;Jawad et al. 2018;Kayaalp et al. 2017;Mane and Bhusari 2012) but with some sort of pretreatment and chemical modifications for enhanced performance (Liu et al. 2019;Lu and Li 2019;Wang and Liu 2017). ...
... Insignificant changes in the adsorption capacity or percent removal was observed afterwards due to the filling of the remaining active sites on the surface of both biochars with MB dye. Similar results have been reported by Tsamo et al. for biochar derived from maize cob attaining 64% removal of MB dye in just 15 min (Tsamo et al. 2019). The maximum adsorption capacity of 478 mg g −1 for OP b observed against 300 mg L −1 of initial MB dye concentration was higher than the previously reported values in literature when using activated carbon of orange peels (Foo and Hameed 2012;Köseoğlu and Akmil-Başar 2015). ...
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Biochar pyrolyzed at 800 °C from banana (Bb) and orange peels (OPb) was applied for sorption of methylene blue (MB) dye in a batch system. OPb showed better affinity for MB dye than Bb with rapid increase in sorption capacity and percent removal for both biochars attaining equilibrium at 30 min. Chemisorption was suggested as the rate limiting step based on the best fitting of the pseudo-second-order reaction kinetics to the batch adsorption data. Linear increase in sorption capacity was seen as the initial MB dye concentration increased from 50 to 300 mg g⁻¹ with a 40 % decrease in removal efficiency. An increase of 90 mg g⁻¹ in sorption capacity for both biochars with a 15 and 30 % increase in removal efficiency for OPb and Bb, respectively, was observed after increasing the solution pH from 2 to 6 or 8. An increase in sorption capacity of about 150 mg g⁻¹ was seen by increasing the biochar dose from 0.1 to 0.5 g. Langmuir isotherm model represented the adsorption data well as reflected by the high values of R² (0.99) when using both biochar, while least representation of adsorption data was seen in H-J isotherm as estimated from very low R² (0.6–0.66) for both types of biochar. An endothermic nature of MB dye sorption was suggested based on the linear increase in sorption capacity with an increase in solution temperature from 30 to 60 °C. This was further confirmed by the observed positive changes in standard entropy and standard enthalpy while negative values of Gibbs-free energies proposed the non-spontaneous natures of MB dye sorption on to both biochars. The effective sorption of MB dye demonstrated the potential of plant-based biochar as economically viable adsorbents for MB dye.