Muhammed Ghassan Aljvanieh’s research while affiliated with Mersin University and other places

Corncob (CC) is an industrial biological waste that is generated in significant quantities, and converting such biological wastes into value-added hydrochars through a viable process such as hydrothermal carbonization can provide significant benefits. It is of great importance to ensure eco-friendly and appropriate methods that are suitable for the area where the hydrochar will be used. This study aimed to synthesize hydrochars from a solid food waste, CC, using two different hydrothermal carbonization methods based on microwave-assisted (MHC) and subcritical water (SHC)using them as a biosorbent for NH4+ adsorption from water and characterizing their specific features. Hydrochars were synthesized in 1 h at 180 °C and 240 °C by MHC and SHC methods, respectively. Hydrochars synthesized by MHC and SHC methods were characterized by SEM-EDX, N2 adsorption-desorption isotherms, and FT-IR analyses. According to the EDX results, the C/O ratio (atomic %) in MHC and SHC was determined to be 0.55 and 0.35, respectively. Nitrogen adsorption-desorption isotherms revealed that hydrochars obtained by both methods have three distinct pore types, namely, micro, meso, and macro. In the energy consumption per unit adsorbent, a lower value was obtained for MHC than SHC. NH4+ adsorption using MHC and SHC was found to be compatible with the Langmuir isotherm model and the NH4+ adsorption capacities were 13.09 and 10.54 mg/g, respectively. pH was the most effective variable on hydrochars in the NH4+ adsorption based on the response surface method (RSM), and the highest adsorption occurred at pH 6.5 and 40 mg/L of initial NH4+ concentration, using 1.5 g/L of adsorbent at 35 °C. The results revealed that MHC is a unique method that can be used for hydrochars derived from CC in NH4+ adsorption, and MHC is more cost-effective than SHC in hydrochar production.

Corncob (CC) is one of the important wastes in Turkey due to its large-scale production and consumption. Efficient disposal of this large-scale waste and even converting it into industrial materials such as hydrochar can provide significant added value. Ammonium, one of the important pollutants in water, should also be reduced below acceptable limits before being discharged into receiving environments. Therefore, this study aimes to synthesize and characterize microwave-assisted (MHC) and subcritical water (SHC) based hydrochars from CCs for ammonium removal from water. For this purpose, it was a goal to determine the effective hydrochar synthesis method for ammonium adsorption. The synthesized hydrochars were characterized by Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX), N2 adsorption-desorption isotherms, and Fourier Transform Infrared (FT-IR) analysis. According to the EDX results, the C/O ratio (atomic %) was determined as 0.55 and 0.35, in MHC and SHC, respectively. Nitrogen adsorption-desorption isotherms revealed that hydrochars obtained by both methods have two different pore types micro and meso. According to the BET theory, the surface areas were calculated as 6.40 m 2 g-1 and 5.20 m 2 g-1 for MHC and SHC, respectively. The maximum pore volume calculated with the Howarth-Kawazoe model was determined as 0.021 cm 3 g-1 for MHC, and 0.016 cm 3 g-1 for SHC. In the energy consumption per unit adsorbent, MHC was lower than SHC. In the ammonium removal studies, the maximum adsorption capacity of MHC and SHC was measured as 13.1 mg g-1 and 10.5 mg g-1 , respectively. As a result, MHC came to the forefront in terms of surface area, maximum pore volume, and energy consumption compared to SHC. It was also seen that MHC was more advantageous than SHC in ammonium removal. The use of synthesized hydrochars from CC in ammonium removal, which creates a serious pollution problem in waters, can make significant contributions to water pollution and control. In addition, the use of hydrochars enriched with ammonium as fertilizer in soil improvement is worth investigating.