Sustainable waste and water management are key components of the newest EU policy regarding the circular economy. Simple, performant and inexpensive water treatment methods based on reusing waste are prerequisites for human health, sustainable development and environmental remediation. The design of performant, cost-effective absorbents represents a topical issue in wastewater treatment. This study aimed to investigate the development of a newly engineered adsorbent by functionalizing two different types of waste (industrial and food) with magnetic nanoparticles as environmentally friendly, highly efficient, cheap material for cadmium removal from aqueous solutions. This nano-engineered adsorbent (EFM) derived from waste eggshell and fly ash was used to remove the cadmium from the aqueous solution. SEM analysis has demonstrated that magnetite nanoparticles were successfully loaded with each waste. In addition, was obtained a double functionalization of the eggshell particles with ash and magnetite particles. As a result of this, the EFM surface area substantially increased, as confirmed by BET. A comprehensive characterization (BET, FT-IR, SEM, XRD and TGA) was performed to study the properties of this newly engineered adsorbent. Batch experiments were conducted to investigate the influence of different reaction parameters: temperature, pH, contact time, dosage adsorbent, initial concentration. Results showed that cadmium adsorption reached equilibrium in 120 min., at pH 6.5, for 0.25 g of adsorbent. The maximum efficiency was 99.9%. The adsorption isotherms research displayed that the Cd2+ adsorption fitted on the Freundlich model indicated a multi-molecular layer adsorption process. In addition, the thermodynamic study (ΔG < 0, ΔH > 0; ΔS > 0) shows that cadmium adsorption is a spontaneous and endothermic process. The adsorbent kinetic study was described with the pseudo-second-order model indicating a chemisorption mechanism. Desorption results showed that the nano-engineered adsorbent (EFM) can be reused. These data confirmed the possibility to enrich relevant theoretical knowledge in the field of waste recovery for obtaining newly designed adsorbents, performant and inexpensive for wastewater remediation.

Reducing the costs associated with water management, improving water quality and the environment are fundamental requirements of sustainable development. Maintaining the optimal level of phosphorus has a direct impact on water quality and the biological system. Current methods used in tertiary wastewater treatment for phosphorus removal present several disadvantages that influence the final water processing cost. Therefore, it is essential for water quality and food safety to develop ecological, cheap and highly efficient materials. This study reported the first comparative assessment of three different types of materials (magnetic, semiconductors and composite) as environmentally friendly, cheap adsorbents for phosphorus removal from wastewater. Several experiments were done to investigate the influence of adsorbent type, dosage and contact time on the efficiency of the processes. The adsorption process was fast and equilibrium was reached within 150 min. We found that the phosphorus adsorption efficiency on of these materials was higher than the chemical method. The obtained results indicated that specific surface area directly influences the performance of the adsorption process. EDS analysis was used to analyze adsorbents composition and analyze the type and content of elements in the substrate before and after reaction with wastewater.

In the current circular economy, innovation is requisite for waste reuse into new efficient materials designed to minimize pollution and conserve non-renewable natural reserves. Water pollution is a global problem with health, quality of life and food security reverberations.In this study were prepared two newly low-cost engineered adsorbents from eggshells for nickel retention from aqueous solutions. SEM results showed that, in the first adsorbent (EZ), the zeolite nanoparticles were loaded in the eggshell pores. The preparation route for the second adsorbent led to the double functionalization of the eggshell with the nano-sized particles of zeolite and simultaneously eggshell pores and zeolite surface loading with FeOOH particles. The eggshell structural modification was confirmed by the BET analysis. These features enabled the proposed adsorbents to remove nickel with high performance and adsorption capacities of 321.11 mg/g and 287.9 mg/g. The adsorption kinetics and isotherm data follow the Freundlich model (ΔG<0, ΔH<0; ΔS>0) and pseudo-second-order kinetics model. These results indicate that nickel adsorption on adsorbents is a multi-molecular layer, spontaneous and endothermic process. Subsequently, the desorption results exhibit the higher reusability of both adsorbents. This study's outcomes conclude the use of waste to design new, low-cost, and highly efficient engineered adsorbents.

In contemporary sustainable economy, innovation is prerequisite to waste recycling into new efficient materials, designed to minimize pollution and conserve non-renewable natural resources. Water pollution is a global problem with health, quality of life, and food safety concerns. Thus, waste conversion into cheap, efficient adsorbent materials with high reusability is a challenge in wastewater recycling. In that context, starting from eggshell waste in this study, two new low-cost engineered adsorbents were prepared for the retrieval of nickel from aqueous solutions. Scanning electron microscopy (SEM) results show that, in the first eggshell-zeolite (EZ) adsorbent, the zeolite nanoparticles were loaded in the eggshell pores. The preparation for the second (iron(III) oxide-hydroxide)-eggshell-zeolite (FEZ) adsorbent led to double functionalization of the eggshell base with the zeolite nanoparticles, upon simultaneous loading of the pores of the eggshell and zeolite surface with FeOOH particles. Structural modification of the eggshell led to a significant increase of the specific surface, as confirmed by BET analysis. These features enabled the proposed adsorbents (EZ and FEZ) to remove nickel from aqueous solutions with high performance and adsorption capacities 321.1 mg/g and 287.9 mg/g, respectively. The results indicate that nickel adsorption on EZ and FEZ is a multi-molecular layer, spontaneous, and endothermic process. Concomitantly, desorption results reflect high reusability of these two adsorbents, collectively suggesting the use of waste in the design of new, low-cost, and highly efficient engineered adsorbents for environmental bioremediation

In contemporary sustainable economy, innovation is prerequisite to waste recycling into new efficient materials, designed to minimize pollution and conserve non-renewable natural resources. Water pollution is a global problem with health, quality of life, and food safety concerns. Thus, waste conversion into cheap, efficient adsorbent materials with high reusability is a challenge in wastewater recycling. In that context, starting from eggshell waste in this study, two new low-cost engineered adsorbents were prepared for the retrieval of nickel from aqueous solutions. Scanning electron microscopy (SEM) results show that, in the first eggshell-zeolite (EZ) adsorbent, the zeolite nanoparticles were loaded in the eggshell pores. The preparation for the second (iron(III) oxide-hydroxide)-eggshell-zeolite (FEZ) adsorbent led to double functionalization of the eggshell base with the zeolite nanoparticles, upon simultaneous loading of the pores of the eggshell and zeolite surface with FeOOH particles. Structural modification of the eggshell led to a significant increase of the specific surface, as confirmed by BET analysis. These features enabled the proposed adsorbents (EZ and FEZ) to remove nickel from aqueous solutions with high performance and adsorption capacities 321.1 mg/g and 287.9 mg/g, respectively. The results indicate that nickel adsorption on EZ and FEZ is a multi-molecular layer, spontaneous, and endothermic process. Concomitantly, desorption results reflect high reusability of these two adsorbents, collectively suggesting the use of waste in the design of new, low-cost, and highly efficient engineered adsorbents for environmental bioremediation