Efficient Iodine Removal by Porous Biochar-Confined Nano-Cu2O/Cu0: Rapid and Selective Adsorption of Iodide and Iodate Ions.

Iodine is a nuclide of crucial concern in radioactive waste management. Nanomaterials selectively adsorb iodine from water; however, the efficient application of nanomaterials in engineering still needs to be developed for radioactive wastewater deiodination. Artemia egg shells possess large surface groups and connecting pores, providing a new biomaterial to remove contaminants. Based on the Artemia egg shell-derived biochar (AES biochar) and in situ precipitation and reduction of cuprous, we synthesized a novel nanocomposite, namely porous biochar-confined nano-Cu2O/Cu0 (C-Cu). The characterization of C-Cu confirmed that the nano-Cu2O/Cu0 was dispersed in the pores of AES biochar, serving in the efficient and selective adsorption of iodide and iodate ions from water. The iodide ion removal by C-Cu when equilibrated for 40 min exhibited high removal efficiency over the wide pH range of 4 to 10. Remarkable selectivity towards both iodide and iodate ions of C-Cu was permitted against competing anions (Cl-/NO3-/SO42-) at high concentrations. The applicability of C-Cu was demonstrated by a packed column test with treated effluents of 1279 BV. The rapid and selective removal of iodide and iodate ions from water is attributed to nanoparticles confined on the AES biochar and pore-facilitated mass transfer. Combining the advantages of the porous biochar and nano-Cu2O/Cu0, the use of C-Cu offers a promising method of iodine removal from water in engineering applications.

Risk assessment of Artemia egg shell-Mg-P composites as a slow-release phosphorus fertilizer during its formation and application in typical heavy metals contaminated environment.

Artemia egg shell loaded with nano-magnesium (shell-Mg) can be used to recover phosphorus from wastewater. The exhausted Artemia egg shell-Mg (denoted as shell-Mg-P) can be used as a slow-release fertilizer for phosphorus reuse. However, due to the coexistence of heavy metal ions in the environment, the application of slow-release fertilizer for phosphorus removal and reuse may have potential risks. In this paper, the potential risks of Pb2+, Cd2+, Zn2+ and Cu2+ in phosphorus wastewater and soil were studied from the formation and application process of shell-Mg-P. The result showed that shell-Mg adsorbed Pb2+, Cd2+, Zn2+ and Cu2+ in phosphate wastewater during the formation of shell-Mg-P and became shell-Mg-P-metal hybrid biomaterial. Although the experiment proved that the existence of heavy metal ions did not affect the phosphorus slow-release behavior of slow-release fertilizer, but the heavy metal ions in the shell-Mg-P-metal were also slow released. The pot experiment results confirmed that the slow-release phosphorus fertilizers (shell-Mg-P and shell-Mg-P-metal) in the soil polluted in low concentration of heavy metals can reduce the amount of heavy metals in whole wheat seedlings and promote wheat seedling growth. However, the application of slow-release fertilizers increased the translocation efficiency (TFR to SL) of metal from root (R) to aboveground part (stem and leaves, SL), promoted the transportation of heavy metals from roots to the stems and leaves, and increased the safety risk of the wheat seedling edible. Therefore, besides the positive role of slow-release fertilizers in retaining heavy metals and reducing the amount of heavy metals in whole seedlings, the risk that it may aggravate the translocation of heavy metals to stems and leaves should be paid more attention, so as to ensure the safe and reliable application of slow-release fertilizers.

Efficient and sustainable phosphate removal from water by small-sized Al(OH)3 nanocrystals confined in discarded Artemia Cyst-shell: Ultrahigh sorption capacity and rapid sequestration.

We reported a new strategy for efficient phosphate removal from wastewaters, it relies on the discarded Artemia Cyst-shell in-situ growth of Al(OH)3 nanocluster, the charged amino-acids components of skeleton make available for the small size of Al(OH)3 formation (< 10 nm) with high activity, and the three-dimensional porous structure of discarded matrix provides fast kinetics and efficient Al(OH)3 nanoparticles utilization. These hybrid adsorbents exhibit ultrahigh capacity (850.5 mg/g) and fast kinetics (~2 min) by recent ten-years (2011-2020) survey, the superior selectivity against various foreign ions, with a distribution coefficient (Kd) as high as 4820 mL/g, the porous structure and fast kinetics also accelerate the phosphate accessibility, yielding a satisfactory capacity of ~3000 L/kg sorbent (Artemia CS-Al) for the application, even varying at high feeding-speeds. The saturated adsorbent can be readily regenerated and reused without decrease in performance, this technology is promising for mitigating the contamination problem of excess phosphate worldwide.

New insight into the bioinspired sub-10 nm Sn(HPO4)2 confinement for efficient heavy metal remediation in wastewater.

Heavy metal pollution poses a severe threat to the water environment. Engineering sub-10 nm active functional materials is an important approach to address the problems, and nanocomposites, developed in recent years by pore confinement always present weaken diffusion and low utilization of nanoparticles. In this study, we successfully prepared the polydopamine confined high-density sub-10 nm Sn(HPO4)2 coating for toxic lead(II) removal and its unique external coating structure and superior active sub-10 nm size achieved remarkable performances for heavy metal remediation. The hybrid sub-10 nm coating exhibits an extended acidic environment application (pH = 2.0-7.0) as well as significant selectivity with a superior Kd values (9.4 × 104 mL/g, which is 450 times greater than that of commercial sulfonated polystyrene. Ultrafast filtrations by vacuum further validate its superior sequestration (near to 100%) to Pb and Cd ions at different concentrations (10-100 mg/L) for 2 mins. The real column application further demonstrates the remarkable capacity of 11800 kg/kg sorbents, the trace effluents with three orders (∼103) reduction to below 1 ppb (> 99.9% Pb removal) and efficient stability for several cycles. The effective performances are mainly driven by the PDA motivated external nanoparticles arrangement and strong inner-sphere complexation by small size of Sn(HPO4)2. These results set a new benchmark for removing toxic metals and the proposed approach (engineering sub-10 nm coating design) is unique for heavy metal removal.

Accelerated Sorption Diffusion for Cu(II) Retention by Anchorage of Nano-zirconium Dioxide onto Highly charged Polystyrene Material.

The development of nanocomposite with strong adsorption ability exhibits great potential applications for environmental remediation. However, the pore blocking in preparation frequently constrains sorption diffusion, resulting in low utilization efficiency. Here we synthesized a new nano-ZrO2/Polystyrene (NZO-PS) material tailored with a specific fixed SO3-Na group to enhance Cu(II) removal. The NZO-PS exhibits efficient Cu(II) sequestration in a wide pH range (3.0-6.5) and preferential sorption performances. The efficient kinetic behavior and column applicability suggest the blocked pore channel is not a matter when presence of negatively charged moiety, which accelerates Cu(II) sorption diffusion and enrichment toward target active site. Moreover, the exhausted NZO-PS can be readily regenerated through HCl-NaCl binary solution. The preparation route can be extended to synthesize other functional composited materials. Simultaneously, the characteristics of simplicity, high-yield and regeneration provide some promising industrial merits.

Rationally designed porous polystyrene encapsulated zirconium phosphate nanocomposite for highly efficient fluoride uptake in waters.

Fluoride pollution in waters has engulfed worldwide regions and an excess of fluoride intake always causes skeletal fluorosis. Herein, a novel hybrid nanomaterial ZrP-MPN was fabricated for fluoride retention by encapsulating nano-ZrP onto macroporous polystyrene materials modified with quaternary ammonium groups. The as-obtained materials exhibited favorable removal of fluoride ions from aqueous solution in presence of common anions (SO4(2-)/NO3(-)/Cl(-)) at high contents. Moreover outstanding sorption properties were also detected by involving series of commercial adsorbents (AA/magnetite/GFH/manganese sands) as references. Such satisfactory performances might be ascribed to the structural design of nanocomposite. (1) the CH2N(+)(CH3)3Cl groups enhances sorption diffusion and preconcentration in sorbent phase theoretically based on Donnan membrane principle; (2) the embedded ZrP nanoparticles also devotes to the efficient adsorption capacities due to its size-dependent specific properties. Additionally, the exhausted ZrP-MPN could be regenerated readily by alkaline solution. Thus, ZrP-MPN was a promising material for fluoride retention in waters.