Inorganic Solutes Research Articles

Aerosol Optical Tweezers Constrain the Morphology Evolution of Liquid-Liquid Phase-Separated Atmospheric Particles

Summary Chemical models of atmospheric particles are vital in understanding the role of aerosol particles in atmospheric chemistry, air pollution, human health, and climate change. Advancing these models requires new frameworks that can realistically predict how critical particle properties evolve. We present such a framework for predicting particle phase separation and which morphology will prevail; this controls how each particle interacts with and affects the atmosphere. We studied the mixing behavior of α-pinene secondary organic aerosol (SOA) with different organic phases, as relative humidity was varied to determine the interplay between polarity, miscibility, interfacial tension, and the resulting morphology. Using measurements from aerosol optical tweezers experiments and literature data, a general trend in morphology with increasing atmospheric oxidation was observed, from biphasic partially engulfed (where both phases are immediately accessible to the gas phase) to biphasic core shell (where the organic shell conceals the core) and finally to a single-phase, homogeneous morphology.

Salt-induced changes in solutes, pigments and essential oil of two basil (Ocimum basilicum L.) genotypes under hydroponic cultivation

The aim of this study was to evaluate the effect of salt stress on the contents of inorganic and organic solutes, pigments and essential oil in two basil genotypes cultivated in hydroponic system. The experiment was carried out in a greenhouse. Treatments were distributed in randomized blocks, in a 2 × 2 factorial arrangement, corresponding to two contrasting genotypes (‘Toscano folha de alface’ (TFA) and ‘Gennaro de menta’ (GM)) and two salt levels (0 - control and 80 mM NaCl), with six replicates. The Na+, Cl- and K+ accumulation in the leaves, stem and roots did not differ between genotypes. Salt stress increased free amino acids accumulation in the leaves of the TFA genotype. The proline content increased in the roots of both genotypes. However, in GM genotype, the proline content (3.12 mmol g-1 dry mass (DM)) was around 2-fold greater when compared to TFA genotype (1.48 mmol g-1 DM). The salt stress increased the photosynthetic pigments content only in the GM genotype. Inorganic solutes and photosynthetic pigments content are not good indicators of salt-tolerance in the studied genotypes. Under salt stress, there was increase in oil content in GM genotype, while the TFA genotype showed a decrease compared to control treatment. In spite of showing lower oil content, the TFA genotype showed higher yield and productivity of essential oil compared to GM under salt stress conditions.

Interactions between feed solutes and inorganic electrolytic draw solutes in forward osmosis

A comprehensive transport model for Forward Osmosis (FO) is presented, based on Maxwell-Stefan theory. In FO, the oppositely directed fluxes give rise to frictional interactions, while the salinity gradient also causes to thermodynamic non-ideal behaviour of organic feed solutes, in the form of salting out. When using electrolytic draw solutes, unequal ion permeance of the draw solute creates an electrostatic potential difference across the membrane, which is an additional driving force for transport of ionic feed solutes. A sensitivity analysis is presented, assessing the effect of frictional interactions, partitioning of feed and draw solutes and salting out on feed solute rejection. It is shown that feed solute rejection is determined primarily by friction with the membrane polymer and partitioning, and secondary by salting out. Frictional interaction between feed and draw solutes is not significant for active layer transport, for a wide range of parameter variation. It can however be significant for transport in the support layer, once feed solutes have permeated through the active layer. Electromigration can be as important as diffusively-driven transport, provided that the length over which the electrostatic potential is established is limited to about the thickness of the active layer. Finally, additional interactions between membranes, organic and inorganic solutes are discussed.

Growth response of Monochasma savatieri to nitrogen, phosphorus, and potassium in the absence of a host plant: essential demand for nutrients of root hemiparasitic plants

Monochasma savatieri Franch. ex Maxim is a perennial, parasitic herb used in traditional Chinese medicine and its wild resources have declined sharply in recent years. For a long time, the research on fertilization of parasitic plants mostly focused on parasitic weeds. Despite its urgent need, there are few studies discussing the nutrient requirements of medicinal threatened parasitic plants. In this study, we investigated the growth response of M. savatieri to inorganic solutes. By using an orthogonal design in pot cultivation, the effects of nitrogen, phosphorus, and potassium on growth traits, haustoria formation, and biomass of M. savatieri were determined under greenhouse conditions. The results showed that M. savatieri had a rather significant growth response to different nutrients supplied. Nitrogen, phosphorus, and potassium significantly influenced growth traits, haustoria formation, and biomass of M. savatieri, but differ in the degree. M. savatieri experienced a more significant increase in nitrogen sufficient than phosphorus or potassium sufficient in terms of seedling height (SH), maximum root length, and biomass. There were significant positive correlations between tested parameters. The regression equation for SH, total leaf length, and number of haustoria both showed relatively high R2 values and could be sensitive available indicators. In the absence of hosts and haustoria-inducing factors, M. savatieri was capable of haustoria formation and autotrophic growth for a period of time. We concluded that M. savatieri had a certain demand for inorganic nutrients. The appropriate supply of inorganic nutrients promoted growth and development of M. savatieri.

Ultrasound-assisted forward osmosis desalination using inorganic draw solutes.

Internal concentration polarization (ICP) represents a serious challenge in forward osmosis (FO) desalination since it causes a significant decline in the water flux across the membrane. Mitigation of ICP is cumbersome since the phenomenon occurs within the membrane porous support layer and mitigation procedures such as inducing turbulence or changing the hydrodynamic conditions tend to be ineffective. In this study, the effect of 40 kHz ultrasound on FO desalination of synthesized brackish and seawater was investigated. The studied process utilizes two different inorganic draw solutes (magnesium and copper sulfate) that are available commercially, can generate high osmotic pressures, and can be easily separated from the product water. Different concentrations of the draw solutions were considered. Results show that the applied ultrasound was effective in partially mitigating the ICP effects and enhancing the water flux. Depending on the feed and the draw solution concentration, flux enhancements of up to 34.6% and 43.9% were observed with magnesium sulfate and copper sulfate draw solution, respectively. In addition, it was observed that the effect of ultrasound on flux enhancement was more evident at lower draw solution concentrations. Although water flux was enhanced, ultrasound resulted in an increased reverse draw solute flux across the membrane.

Population structure and developmental stage‐associated ecophysiological responses of Salicornia brachiata

Abstract Salicornia brachiata (Roxb.) is an important euhalophyte for ecological rehabilitation of salt‐affected soil. The aim of this study was to investigate the population structure of S. brachiata and evaluate its ecophysiological responses throughout its lifespan. Six different salt marshes along the Gujarat Coast, India, were visited regularly to monitor and quantify the ecophysiological responses of S. brachiata. Vegetation index analyses confirmed the dominance of halophytic vegetation at these sites. The low solute potential in shoots of S. brachiata helped plants to conserve water and use water economically under physiologically dry conditions. The accumulation of Na+ increased as the plants matured, while K+, Mg+2 and Cl− contents decreased. There was a higher proportion of inorganic solutes than organic solutes throughout the lifespan of S. brachiata. The estimated contributions of different solutes to osmotic adjustment were consistent with their accumulation levels. The estimated contribution of inorganic solutes to solute potential was significantly higher than that of organic solutes. The results indicated that the uptake of inorganic solutes generated a more negative solute potential, which helped plants to conserve water and save the energy required to synthesize the organic solutes to maintain osmotic homeostasis. The results of this study provide physiological insights into the role of inorganic solutes in the salt acclimation process and reveal aspects of the salt acclimation strategies of this euhalophyte. This information will be useful for predicting the impact of S. brachiata populations on halophytic vegetation and for designing saline‐agriculture strategies for optimum yields in degraded salt‐affected soil ecosystems.

Sensitivity and biochemical mechanisms of sunflower genotypes exposed to saline and water stress

Crops tolerant to salt and drought stress are an excellent alternative for producers in semi-arid regions. However, it is necessary to select the crops more tolerant and understand their involved mechanisms. We evaluated the effects of salinity and drought on growth, water status, membrane integrity, as well the behavior of organic and inorganic solutes in sunflower genotypes. Greenhouse experiments were performed to evaluate the tolerance of sunflower genotypes (Catissol 01 and Helio 253) to the salt and drought stress. The salt and drought stress were simulated by sodium chloride (NaCl) and polyethylene glycol (PEG 6000), respectively. The treatments with NaCl and PEG 6000 induced adverse changes on the growth, water status and cell membranes of the sunflower plants. Sunflower genotypes are more sensitive to water deficit due to the higher osmotic imbalance. The presence of saline ions minimized damages in sunflowers genotypes caused by lower water potential. The Catissol 01 genotype accumulated Na+ in the stem and roots avoiding translocation to the leaves. Helio 253 showed higher tolerance to the salt and drought stress than Catissol 01. Salinity and drought caused alterations on the carbohydrates and nitrogen compounds of the two sunflower genotypes. Soluble sugars, soluble proteins, free amino acids, and proline participate differently in the osmotic adjustment of the genotypes. The accumulation of soluble sugars, soluble proteins, and proline in the leaves is a mechanism that increases the tolerance to the salt and drought stress in the Helio 253 genotype.

Energy costs of salinity tolerance in crop plants: night-time transpiration and growth.

Plants grow and transpire during the night. The aim of the present work was to assess the relative flows of carbon, water and solutes, and the energy involved, in sustaining night-time transpiration and leaf expansive growth under control and salt-stress conditions. Published and unpublished data were used, for barley plants grown in presence of 0.5-1mM NaCl (control) and 100mM NaCl. Night-time leaf growth presents a more efficient use of taken-up water compared with day-time growth. This efficiency increases several-fold with salt stress. Night-time transpiration cannot be supported entirely through osmotically driven uptake of water through roots under salt stress. Using a simple three- (root medium/cytosol/vacuole) compartment approach, the energy required to support cell expansion during the night is in the lower percentage region (0.03-5.5%) of the energy available through respiration, under both, control and salt-stress conditions. Use of organic (e.g. hexose equivalents) rather than inorganic (e.g. Na+ , Cl- , K+ ) solutes for generation of osmotic pressure in growing cells, increases the energy demand by orders of magnitude, yet requires only a small portion of carbon assimilated during the day. Night-time transpiration and leaf expansive growth should be considered as a potential acclimation mechanism to salinity.

Interactive effects of salinity and nitrogen forms on plant growth, photosynthesis and osmotic adjustment in maize

To enhance crop productivity and minimize the harmful effects of various environmental stresses, such as salinity and drought, farmers often use mineral fertilizers. However, inadequate or excessive fertilization can reduce plant growth and nutritive quality and contribute to soil degradation and environmental pollution. This study investigated the effects of salinity (0, 100 or 150 mM NaCl) and nitrogen form (sole NO3− or NH4+, or combined NO3−:NH4+ at 25:75 or 50:50) on growth, photosynthesis, and water and ion status of a commercial variety of maize (Zea mays SY Sincero). In the absence of NaCl, the media containing ammonium only or both nitrogen forms had higher aboveground growth rates than that containing nitrate only. Indeed, the maize growth, expressed as leaf dry matter, seen on NH4+ in the absence of salinity, was nearly double the biomass compared to that with NO3−treatment. Irrespective of N form, the presence of NaCl severely reduced leaf and roots growth; the presence of ammonium in the nutrient solution diminished these negative effects. Compared to the NH4+ only and combined treatments, the leaves of plants in the NO3−-only medium showed signs of nitrogen deficiency (general chlorosis), which was more pronounced in the lower than upper leaves, indicating that nitrate is partly replaced by chloride during root uptake. NH4+ favored maize growth more than NO3−, especially when exposed to saline conditions, and may improve the plant's capacity to osmotically adjust to salinity by accumulating inorganic solutes.

Differential Incorporation of Bacteria, Organic Matter, and Inorganic Ions Into Lake Ice During Ice Formation

AbstractThe segregation of bacteria, inorganic solutes, and total organic carbon between liquid water and ice during winter ice formation on lakes can significantly influence the concentration and survival of microorganisms in icy systems and their roles in biogeochemical processes. Our study quantifies the distributions of bacteria and solutes between liquid and solid water phases during progressive freezing. We simulated lake ice formation in mesocosm experiments using water from perennially (Antarctica) and seasonally (Alaska and Montana, United States) ice‐covered lakes. We then computed concentration factors and effective segregation coefficients, which are parameters describing the incorporation of bacteria and solutes into ice. Experimental results revealed that, contrary to major ions, bacteria were readily incorporated into ice and did not concentrate in the liquid phase. The organic matter incorporated into the ice was labile, amino acid‐like material, differing from the humic‐like compounds that remained in the liquid phase. Results from a control mesocosm experiment (dead bacterial cells) indicated that viability of bacterial cells did not influence the incorporation of free bacterial cells into ice, but did have a role in the formation and incorporation of bacterial aggregates. Together, these findings demonstrate that bacteria, unlike other solutes, were preferentially incorporated into lake ice during our freezing experiments, a process controlled mainly by the initial solute concentration of the liquid water source, regardless of cell viability.

The Dependence of Radius on Relative Humidity and Solute Mass at High Relative Humidities Up to and Including 100%

AbstractThis manuscript presents a rigorous examination of the equilibrium radius ratio of hygroscopic aerosol particles that are solution drops of ideal and actual inorganic solutes for a range of solute masses in the relative humidity range 99–100%. Analysis is presented first for ideal solutes over a range of solute masses for different hygroscopicities, providing a theoretical framework for the subsequent analysis of actual solutes. Dimensionless quantities are used to reduce the Köhler equation to one with no free parameters and an approximate solution is presented. Next analysis is presented for three common inorganic solutes of atmospheric importance: sodium chloride, ammonium sulfate, and sulfuric acid, with a range of solute masses considered for each substance. The extent to which nonideality is important for these solutes over the ranges of relative humidities and solute masses considered is examined. A simple but accurate single‐parameter expression is presented for the equilibrium radius ratio as a function of relative humidity that contains the dependences on solute mass and composition for these solutes. The accuracy of this expression is quantified and factors that limit this accuracy are discussed. The expression is accurate to within 5% over most of the range of mass‐equivalent dry radii from 10 to 250 nm and relative humidities from below 99 up to 100%, over which the equilibrium radius ratio varies by more than a factor of 5, and it remains finite at 100% relative humidity. Finally, measurements of hygroscopic growth of aerosol particles in this relative humidity range are discussed.

Lateral Transport of Organic and Inorganic Solutes.

Organic (e.g., sugars and amino acids) and inorganic (e.g., K+, Na+, PO42−, and SO42−) solutes are transported long-distance throughout plants. Lateral movement of these compounds between the xylem and the phloem, and vice versa, has also been reported in several plant species since the 1930s, and is believed to be important in the overall resource allocation. Studies of Arabidopsis thaliana have provided us with a better knowledge of the anatomical framework in which the lateral transport takes place, and have highlighted the role of specialized vascular and perivascular cells as an interface for solute exchanges. Important breakthroughs have also been made, mainly in Arabidopsis, in identifying some of the proteins involved in the cell-to-cell translocation of solutes, most notably a range of plasma membrane transporters that act in different cell types. Finally, in the future, state-of-art imaging techniques should help to better characterize the lateral transport of these compounds on a cellular level. This review brings the lateral transport of sugars and inorganic solutes back into focus and highlights its importance in terms of our overall understanding of plant resource allocation.

Heat Tolerance Screening Studies and Evaluating Salicylic Acid Efficacy against High Temperature in Rice (Oryza sativa L.) Genotypes

High temperature retards plant growth and development. Major objective of this study was to assess heat tolerant potencies of forty rice cultivars at seedling stage and check the effectiveness of salicylic acid (SA) in improving thermo-tolerance. Rice seeds were sown in plastic bowls containing sand and heat stress (45°C) was applied on 15- days old seedlings for 12 and 24 h in growth incubators. Growth related stress tolerance indices were used as screening tools. Among all, two heat sensitive (Rambir and DM 15-1) and heat tolerant (RP2 and DM1-30-15-04) cultivars were selected for SA studies. SA spray (100 mg L-1) was used on 15-days old seedlings and heat stress (45°C) was imposed on 19-days old seedlings for 12 h and 24 h. Growth (root and shoot lengths and fresh and dry biomasses) and biochemical attributes (nitrate and nitrite reductase, total soluble sugars, proteins, nitrogen, potassium, phosphorous and magnesium) were measured. Heat shock reduced seedling growth, enzymatic activities and mineral contents. However, SA enhanced fresh and dry biomass, concentration of organic and inorganic solutes in all genotypes under heat stress. SA improved thermo-tolerance in RP2 and DM1-30-15-04 genotypes. These heat tolerant genotypes have capability to give better seedling growth and stand establishment.

Characterization and implications of solids associated with hydraulic fracturing flowback and produced water from the Duvernay Formation, Alberta, Canada.

Public concern is heightened around flowback and produced water (FPW) generated by the hydraulic fracturing process. FPW is a complex mix of organic and inorganic solutes derived from both the injected hydraulic fracturing fluid and interactions with the subsurface lithology. Few studies to date have systematically investigated the composition of FPW or its individual components. Here, we provide the first systematic characterization of the composition of the solids associated with FPW by analyzing samples from three wells drilled into the Duvernay Formation in Alberta, Canada. The FPW initially returned to the surface with high total dissolved solids (greater than 170 000 mg L-1) and enriched with Fe(ii), silica, sulfate, barium, and strontium. The solids form two distinct phases once the FPW reached the surface: (1) silica-enriched Fe(iii) oxyhydroxides, and (2) a barite-celestine solid solution. We hypothesize that the precipitation of the amorphous silica-enriched Fe(iii) oxyhydroxide is a two-step process, where first the silica precipitates as a function of the cooling of the FPW from elevated subsurface temperatures to ambient surface temperatures. Next, the silica acts as a template for the precipitation of Fe(iii) oxyhydroxide as the diffusion of oxygen into the subsurface causes oxidation of aqueous Fe(ii). The barite-celestine solid solution precipitates solely as a function of cooling. Elevated dissolved Fe concentrations in FPW and modeled saturation indices from five North American shale plays (Marcellus, Fayetteville, Barnett, Bakken, and Denver-Julesburg) indicate that solids similar to those found in Duvernay FPW, specifically Fe(iii) oxyhydroxides, barite and quartz, are likely to occur. With the solids known to carry a significant portion of FPW's toxicity and organic contaminant load, the development of new treatment technologies, such as the oxidation of the Fe(ii) in FPW, may increase FPW reuse and reduce the environmental risk posed by FPW.

Evaluation of Different Extracting Methods of Inorganic Solutes (Na, K & Ca) Determination in Wheat for Salinity Screening Programs

A detailed study was conducted to compare different extraction/ digestion methods (Solute extraction by water (cold and hot), Solute extraction by weak acid (Acetic acid,CH3COOH), Solute extraction by organic solvent (toluene), direct total analysis by wet oxidation (H2SO4, H2O2) and direct total analysis by wet oxidation (HClO4 : HNO3) in 1:5 ratio), for determination of inorganic solutes especially (Na, K and Ca), to select most suitable, accurate efficient, and economical analytical methods for ionic analysis for smooth running of salt screening programs. Wheat crop was selected as test crop under saline and non-saline environments to observe the effect of genotypic and environmental variability on extracting methods. It was observed that there is wide variation in ionic contents among the extraction/ digestion methods. It was also observed that the determination of inorganic solutes especially (Na, K and Ca), by extracting method with 0.5% toluene water is highly correlated with wet digestion either by Nitric per chloric acid (HClO4: HNO3) in 1:5 ratio or sulphuric acid and hydrogen per oxide (H2SO4, H2O2). The extraction with 0.5% toluene water is safe, economical and efficient, therefore it is highly recommended to adopt the Solute extraction by organic solvent (toluene) method for salinity screening programs.

Effect of salinity on osmotic adjustment, proline accumulation and possible role of ornithine-δ-aminotransferase in proline biosynthesis in Cakile maritima.

The short time response to salt stress was studied in Cakile maritima. Plants were exposed to different salt concentrations (0, 100, 200 and 400mM NaCl) and harvested after 4, 24, 72 and 168h of treatment. Before harvesting plants, tissue hydration, osmotic potential, inorganic and organic solute contents, and ornithine-δ-aminotransferase activity were measured. Plants of C. maritima maintained turgor and tissue hydration at low osmotic potential mainly at 400mM NaCl. The results showed that, in leaves and stems, Na+ content increased significantly after the first 4h of treatment. However, in roots, the increase of Na+ content remained relatively unchanged with increasing salt. The K+ content decreased sharply at 200 and 400mM NaCl with treatment duration. This decrease was more pronounced in roots. The content of proline and amino acids increased with increasing salinity and treatment duration. These results indicated that the accumulation of inorganic and organic compounds was a central adaptive mechanism by which C. maritima maintained intracellular ionic balance under saline conditions. However, their percentage contribution to total osmotic adjustment varies from organ to organ; for example, Na+ accumulation mainly contributes in osmotic adjustment of stem tissue (60%). Proline contribution to osmotic adjustment reached 36% in roots. In all organs, proline as well as δ-OAT activity increased with salt concentration and treatment duration. Under normal growth conditions, δ-OAT is mainly involved in the mobilization of nitrogen required for plant growth. However, the highly significant positive correlation between proline and δ-OAT activity under salt-stress conditions suggests that ornithine pathway contributed to proline synthesis.

Differential physiological responses of Tunisian wild grapevines (Vitis vinifera L. subsp. sylvestris) to NaCl salt stress

The effects of salt stress on growth, organic and inorganic solute accumulation and chlorophyll florescence were studied on 3-month-old plants of six Tunisian wild grapevine accessions in order to identify salt tolerance mechanisms and select tolerant genotypes. Potted plants were grown under controlled conditions and irrigated for 14 days with 0, 100 and 150 mM NaCl Long Ashton nutrient solution. Salt begins to adversely affect plant growth and plant nutrition at 100 mM NaCl. Compared to control, shoot growth rates were 21.5% less for Khedhayria, Tebaba and Ouchteta, 33% for Djebba and Zouarâa and 49% for Houamdia. They were assigned to stomatal and non-stomatal factors. Stomatal conductance decreased after 1 day at 150 mM NaCl in all accessions in response to reduced leaf water potential. Leaves in tolerant accessions were well hydrated through efficient osmotic adjustment, sufficient potassium flux and selectivity of K+ versus Na+. In addition, salt tolerance of wild grapes was related to limiting Na+ transport to lamina and to compartmentalization of Cl− on root and leaf vacuoles, improved in Tebaba and Khedhayria by the uptake of K+. At the same time, disturbances of the PSII have been noted as non-stomatal factors, and the most important photoprotective mechanism against photosynthetic damages was non-photochemical energy dissipation. However, chlorophyll fluorescence parameters were more stable in Tebaba compared to Khedhayria, thus showing better salt tolerance. Based on our results, wild grapevine accessions could be classified from most tolerant to most sensitive as follows: Tebaba > Khedhayria > Ouchteta > Zouarâa > Djebba > Houamdia.

Unusual drying behaviour of droplets containing organic and inorganic solutes in superheated steam

There are currently limited studies on the effect of superheated steam (SHS) on the solidification behaviour of droplets with dissolved solids which is a core phenomenon in spray drying. In this work, the single droplet drying technique was used to investigate how SHS affects the particle formation process of organic sugar droplets (lactose and mannitol), protein droplets (whey protein isolate) and droplets containing inorganic solute (sodium chloride). Unexpected droplet drying phenomenon was observed differing from drying behaviour typically assumed in the literature. While SHS is well known to result in slower drying rates below the inversion temperature, it also exhibits a lower potential to remove moisture at the end point ‘pseudo-equilibrium’ stage of drying. This led to lactose and mannitol droplets encountering incomplete moisture removal challenges in its drying process. The higher constant rate drying temperature experienced by droplet in SHS led to the precipitation of ultrafine protein particles. This higher constant rate drying temperature also led to the production of inverted pyramidal shaped salt crystals highlighting the potential of SHS as a useful medium for spray drying crystallization control.

Growth, relative chlorophyll content and concentration of inorganic solutes in sunflowers plants supplemented with marine macroalgae organic residue

ABSTRACT One effect of the tidal dynamics is the accumulation during the low tide of large volumes of macroalgae, named “arribadas algae”. The objective of this work was to analyze the effects of using arribada alga e organic residues (AAOR) on the initial growth of sunflower plants, where the following were evaluated: plant growth, relative chlorophyll content and inorganic solids content (Na, K, Cl and NO3). The algae were collected on Praia do Pacheco in Caucaia, state of Ceará, Brazil, washed in running water and placed to dry in the sun for seven days, then dried in a forced circulation oven at 80 ºC and crushed. The sunflower seeds were sown in 5L plastic buckets, containing: 1) 100% (in volume) of sand; 2) sand + 100% of nitrogen recommendation - NR in commercial fertilizer (80kg of N.ha-1); 3) sand + 50% of the NR in macroalgae; 4) sand + 100% of NR in macroalgae; and 5) sand + 150% of the NR in macroalgae. The use of AAORimproved the growth of the analyzed variables in relation to the plants grown in substrate with sand or sand + fertilizer. The best results were observed at 50% of the NR in AAOR. The addition of increasing concentrations of AAOR allowed a greater accumulation of beneficial ions such as K and NO3 while no significant differences were observed for toxic ions such as Na and Cl in relation to plants supplemented with fertilizer or sand. The use of AAOR in substrates can be an alternative to fertilizers in plant cultivation since it reduces production costs besides being a sustainable destination.

Performance evaluation of hybrid OMBR-MD using organic and inorganic draw solutions.

The performance of two inorganic divalent salts (CaCl2, and MgCl2) and two organic salts (CH3COONa and Mg(CH3COO)2) was compared with commonly used NaCl in an osmotic membrane bioreactor (OMBR) integrated with a membrane distillation (MD) system. The system was investigated in terms of salinity buildup, flux stability, draw solution (DS) recovery and contaminants removal efficiency. Results indicated that organic DSs not only lessen the salt accumulation within the bioreactor but also increase the pollutant removal efficiency by improving biological treatment. Of all the draw solutions, NaCl and CaCl2 produced rapid declines in water flux because of the high salt accumulation in the bio-tank as compared to other salts. The DCMD system successfully recovered all organic and inorganic draw solute concentrations as per OMBR requirements. Membrane flushing frequency for the MD system followed the order Mg(CH3COO)2 > CH3COONa > CaCl2 > MgCl2 > NaCl. More than 90% removal of chemical oxygen demand (COD), NH4 +-N, and PO4 3--P was achieved in the permeate for each salt because of the dual barriers of high-retention membranes i.e., forward osmosis and MD.