Salted anchovy bones are a non-recyclable waste product containing high salt levels. However, they also contain valuable minerals such as calcium, phosphorus, potassium, magnesium, and nitrogen. This ...study aimed to find a cost-effective method to desalinate anchovy bones while preserving their nutritional value and repurposing them as a raw material for poultry feed. Through various tests, we were able to reduce the salt content of the anchovy bones from 15.4% to 4.7% using a 50/50 percent mixture of tap water and from 15.4% to 3.7% using a mixture of tap water and soybean meal in a 30/70 percent ratio. Combining soybean meal with desalted anchovy bones resulted in a nutritional composition comparable to that found in poultry feed, reducing salt content. The response surface method (RSM) was employed to determine the optimal proportions of desalted anchovy bones (70-90%) and soybean meal (10-30%) and to study the variables affecting the concentrations of NaCl, Ca, P, Ash, and TNM. The study revealed the influence of desalted anchovy bone and soybean meal percentages on these concentrations. This study demonstrates that the method used provides an ideal approach for understanding the interactions between input parameters (% DAR, % SM) and output parameters (NaCl, Ca, P, Ash, and TNM) and shows promising results for the desalination of anchovy bones using a soybean meal cake as well as the feasibility of creating poultry feed.
Reject desalination brine is a rich source of salts and valuable materials. But, its disposal into the external environment generates a major source of pollution. This paper investigated the ...production of reactive CaO from reverse osmosis (RO) reject brine and its use as adsorbent for phosphate removal from contaminated seawater and RO industrial waste. This study was realized via two steps. Firstly, the recovery of Ca-phase from reject brine via oxalic acid at optimized conditions resulting clcium oxalate monohydrate, and its calcination at 900°C for 2 h to produce the reactive CaO. Secondly, the produced reactive CaO was doped by Fe3O4 via co-precipitation method to produce reactive CaO@Fe3O4 composites. The reactive CaO@Fe3O4 was explored as a potential adsorbent with enhanced capacity for phosphate ions (PO43−) removal. The estimated maximum reactive CaO@Fe3O4 uptake capacity for PO43− (106.3 mg/g) is comparatively higher than the identified values for the reactive CaO (72.8 mg/g) and Fe3O4 (41.6 mg/g). The kinetics of the PO43− uptake reaction via reactive CaO@Fe3O4 obey the Pseudo-Second order model (R2 > 0.98) and the equilibrium time was determined after 450 min. The equilibrium study of the demonstrated reaction exhibited excellent agreement with the isotherm assumption of the Freundlich model implying multilayer and heterogeneous adsorption processes. The thermodynamic aspect of PO43− adsorption reaction is favorable and exothermic. The adsorbent selectivity, reusability experiments and realistic study were also discussed . Furthermore, the computational study using DMs was applied to better understand the interaction for {PO43−/CaO(111)&CaO@Fe3O4(111)} systems. The simulation results demonstrate favorable, more stable, spontaneous adsorption and exothermic for PO43−/CaO@Fe3O4(111) than PO43−/CaO(111)complex. Overall, CaO@Fe3O4(111) could serve as a effective and reusable adsorbent for phosphate ions recovery from aqueous solutions.
