Influence of Salting Technology on the Diffusion of NaCl in Swordfish (Xiphias gladius) Fillets

Swordfish is the most widespread billfish in the aquatic environment. The industrial processing of swordfish fillets involves salting, drying, and smoking steps. Salting techniques, dry or wet, are the most common method of fish preservation. This work evaluated salt diffusion in swordfish fillets after traditional dry salting and wet industrial injection salting methods. The data obtained from the dry salting studies highlighted that the salt diffusion process in swordfish meat was an unfavorable process depending on the contact time with the salt/meat. Moreover, irregularly shaped fillets negatively affected the salt migration in the different areas, leading to inhomogeneous and possibly unsafe final products. On the contrary, wet injection salting was suitable for processing swordfish fillets. As a result, the final products had a homogeneous salt concentration, maintained the organoleptic characteristics and health benefits for a long period, and achieved a longer shelf-life. Furthermore, the water activity (aw) values detected for the different processed fillets confirmed the physicochemical features of the final products and allow the classification of safe products. Moreover, injection salting is a quick process compatible with industrial production times.

A Comparison between Evaporation Ponds and Evaporation Surfaces as a Source of the Concentrated Salt Brine for Salt Gradient Maintenance at Tajoura’s Solar Pond

One of the main problems that negatively affect the operation of salt gradient solar ponds and influence its thermal stability is the maintenance of salt gradient profile. Evaporation pond (EP) is designed to generate the salt which is lost by upward salt diffusion from the lower convective zone (LCZ) of the solar pond. Another attractive method is the Evaporation Surface facility (ES). Regions with moderate to high precipitation favor Evaporation Surfaces over Evaporation Ponds. Dry climates will generally favor Evaporation Ponds for the brine re-concentration. This paper investigates the differences between (EP) and (ES) both as a source for salt brine generation by evaporation. The effect of (EP) depth on the area ratio and daily variations of salt concentrations for three years of operation is shown. Results show that evaporation can be a reasonable method for salt brine generation. Reducing the depth of (EP) improves the capability of (EP) for brine re-concentration. It also increases the (EP) surface area for the same quantity of saline water used. Therefore, ESs are more powerful than Eps in salt re-concentration.

Ultrafast transformation of PbI2 in two-step fabrication of halide perovskite films for long-term performance and stability via nanosecond laser shock annealing

Nanosecond laser shock annealing is used to induce ultrafast organic salt diffusion into the PbI2 layer to modulate the crystalline structure, residual tensile strain, and electron transport kinetics of perovskite films.

Highly Salt-Resistant and All-Weather Solar-Driven Interfacial Evaporators with Photothermal and Electrothermal Effects Based on Janus Graphene@Silicone Sponges

Solar-driven interfacial evaporators are very promising for obtaining clean water, but suffer from serious performance degradation by salt-fouling, low evaporation rate under weak illumination and low clean water collection rate. Here, we report highly salt-resistant and all-weather evaporators with photothermal and electrothermal effects based on the Janus graphene@silicone sponges with opposing wettability. The evaporators achieve a remarkable high evaporation rate of 6.53 kg m-2 h-1 for 3.5 wt% NaCl solution under 1 sun illumination with a 5 V solar cell as compensation owing to their high solar absorption, low thermal conductivity, unique Janus structure and synergetic photothermal and electrothermal effects. Even in gloomy and dark environments, the evaporators could still generate vapor (1.51 kg m-2 h-1). Moreover, the evaporators feature long-term excellent salt-resistance, e.g., >10 d continuous evaporation in 10 wt% NaCl solution without performance degradation and salt precipitation, because of ultrafast water supply and salt diffusion in the macroporous superhydrophilic shell. Furthermore, the evaporators show high clean water collection rates of 21.92 kg m-2 d-1 (1 sun-9 h/0 sun-15 h + 5 V, indoor) and 9.65 kg m-2 d-1 (natural sun light + 5 V, outdoor). This study offers a new approach for efficiently obtaining clean water via solar desalination.

INFLUENCE OF SALT DIFFUSION ON THE STABILITY OF METHANE GAS HYDRATE IN THE ARCTIC SHELF

Suitable conditions for the formation of methane hydrates exist in the bottom sediments of shallow Arctic shelves in the presence of permafrost. Salt diffusion into hydrated bottom sediments can help accelerate hydrate degradation. An analysis of the influence of salinity of the bottom sediments of the Arctic shelf on the thickness of the methane hydrate stability zone was based on mathematical modeling. Estimates of the thickness of the stability zone were obtained in experiments with various correlations which relate the hydrate dissociation temperature in the presence of aqueous solutions containing salts.

Apparent salt diffusion coefficients for soil–bentonite backfills

Apparent diffusion coefficients, Da, were measured for two soil–bentonite (SB) backfills characteristic of those used in SB vertical cutoff walls for subsurface control of contaminant migration. The base soils for the backfills comprised either a natural lean clay or sand–bentonite mixtures. The base soils were mixed with 5% bentonite–water slurry to obtain a slump of 125 mm, resulting in total bentonite contents ranging from 4.76% to 7.31%. Values of Da for sodium chloride were measured using a recently developed dialysis-leaching test method. The Da values for the clay–bentonite and sand–bentonite backfills ranged from 2.5 × 10−10 to 5.3 × 10−10 m2/s and from 1.4 × 10−10 to 8.1 × 10−10 m2/s, respectively. Values of Da for both backfills increased with increasing average salt concentration in the specimen (Cave). Values of Da decreased by ≤50% with increasing backfill bentonite content. For all Cave values, the clay backfills exhibited lower Da than the sand–bentonite backfills, likely due to additional fines from the lean clay. Results of this study enhance understanding of solute diffusion through SB cutoff walls, as well as support future use of the dialysis-leaching test method to measure diffusion properties of SB backfills.