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Aims: In this study, biochar and magnetic biochar were obtained from loquat seeds. The obtained biochars were used to remove methyl blue from the aqueous solution. Study Design: The effects of adsorbent substance dosage, pH, initial methyl blue concentration, time and temperature on the adsorption process were investigated. Place and Duration of Study: Department of Chemistry, Graduate School of Applied and Natural Sciences, Süleyman Demirel University, between February 2022 and February 2023. Methodology: In this study, batch adsorption method, which is an easily applicable and common method, was used to remove dye from aqueous media. Modified loquat seeds were characterized by FTIR, BET analysis. The adsorption process was investigated in terms of kinetics, equilibrium and thermodynamics. Results: The maximum adsorption capacity was 31.746 mg/g for biochar and 67.568 mg/g for magnetic biochar. According to the kinetic data, the adsorption rate is pseudo-second-order. According to the thermodynamic data, negative ΔG values indicated that adsorption of methyl blue occurred spontaneously. According to negative ΔH values, the adsorption process was exothermic. When the adsorption isotherms were examined, it was seen that loquat biochar and modified loquat biochar were suitable for the Langmuir adsorption isotherm. Conclusion: Modified loquat seeds can be used to remove methyl blue dye from aqueous solutions. The adsorbents used can be modified with different chemicals to increase the adsorption capacity and contribute to the literature.

Aims: The aim of the study was to use Response Surface Methodology (RSM) to find optimal experimental design for wastewater treatments from office paper recycling. In this way, interactive effects of treatment factors were evaluated, including microwave power (MW) and durations with centrifuge time while turbidity of wastewater was chosen as the dependent output variable or an optimal response. Methodology: The RSM approach was utilized for optimization of the process parameters and identifying the optimal conditions for the removal of turbidity in paper recycling wastewater. In this regard, a three-factor RSM were selected, using MW irradiation power (Watts), durations (seconds) and centrifuge time (min). Statistical analysis of variance (ANOVA) was carried out to identify the adequacy of the developed model. In this case, specially prepared office papers (one-side laser printed) were subjected to standard paper recycling procedure for obtaining wastewater at laboratory conditions. The experimentally derived RSM model was validated using range of statistical parameters. Conclusions: The study revealed that under the RSM optimized conditions, a marked reduction in the turbidity of wastewater was observed for both groups studied. The R2, R2(adj) and R2(pred) values were indicates, the developed model was significant which revealed a well agreement between the experimental data and proposed model. In this approach, the R2=99.710% and lack-of-fit value were found to be 0.111 (p>0.05), which shows the model and the data consisted to each other. The lowest turbidity value was found with 150.000 Watts and 60.000 seconds in MW conditions with 15.000 minutes of centrifugation time, experimentally. With employing these variables, the turbidity value of 6.65 NTU was determined. However, the highest turbidity value of 18.013 NTU was found with MW power of 200.00 Watts with 40.000 seconds of durations and 1.591 minute of centrifugation time. It is important to note that with using optimized parameters, the turbidity value of 1.43 NTU was calculated while 1.47 NTU was found with experimentally.