The removal of Acid Red 114 (AR114) dye by adsorption process, using the magnetic nanoparticle (RHA-MNP) which is produced from rice husk ash burned at 300°C and the magnetic nanoparticle (MNP, Fe₃O₄), was studied. Batch processes were used under different test parameters: pH (2, 4, 6, and 10) and without pH, initial dye concentration (20, 40, 60, 80, and 100 mg/L), and contact time (0, 1, 5, 10, 15, 30, 45, 60, 90, and 150 min). Optimum conditions for AR114 removal were found to be at natural pH (pH without correction) for both adsorbents. Freundlich isotherm was found to be more consistent for MNP and Langmuir isotherm was found to be more consistent for RHA-MNP. The maximum adsorption capacities of MNP and RHA-MNP adsorbents for AR114 dye were equal to 111 mg/g. The kinetic experimental data fitted the pseudo-second-order model for both MNP and RHA-MNP. It can be concluded that RHA-MNP which is a waste could be used as low-cost adsorbent to remove AR114 from aqueous solution.

The objective of this study is to evaluate the performance of H₂SO₄− activated rice husk ash (ARHA) (burned at different temperatures (300–550°C) as compared to granular activated carbon (GAC) in the removal of methylene blue (MB) from aqueous solution. Batch studies were performed to evaluate the influences of various experimental parameters like pH (4, 7, 9, and 11), initial concentration (5, 10, 15, 20, 25, and 50 mg/L), and contact time (0, 1, 5, 15, 30, 45, 60, 90, and 120 min). BET surface areas for ARHA300 (burned at 300°C) and ARHA550 (burned at 550°C) were determined as 143 and 68 m²/g, respectively. It was observed that the dye uptake by GAC and ARHA300 were not changed significantly when the pH of dye solution was increased from 4 to 11. Uptakes of dye were rapid and the adsorption increased with increasing contact time in all experiments. According to the R² values for the adsorption of MB on ARHA300, ARHA500, and GAC, Langmuir model yields fit better than the Freundlich model. The maximum adsorption capacity, q_max of ARHA300 (44.25 mg/g), had the highest value. The pseudo-second-order kinetic model yields the best fit for adsorption on ARHA300 and ARHA550 and the correlation coefficients R² of the model for the linear plots are very close to 1 at various concentrations.

In this study, the situation of waste management and zero waste applications in educational institutions was investigated in Turkey. For this purpose, the wastes collected and separated within the scope of zero waste and the wastes collected without separating them in trash cans were determined at certain periods and the total amount of waste generated per unit time and per person was calculated for an engineering faculty, vocational school, high school and primary school. A questionnaire study was conducted to determine the viewpoints of the students studying at the engineering faculty on zero waste management. According to the obtained data, the amount of waste collected in the faculty was calculated as 184 kg day-1 and only 27 kg day-1 of this amount is being recycled. Considering all types of waste in the whole schools, waste generation rates were found to be 17,6, 32,3, 93,7 and 113 g person-1 day-1 respectively for primary school, high school, vocational school, and engineering faculty. One of the important results obtained in the study is that the necessary training and awareness-raising activities in zero waste implementation are very important, and every stage from the reduction of the number of trash cans to the correct placement of zero waste sets requires detailed planning.