Abstract:Brine discharge of reverse osmosis (RO) desalination plants represents a challenge for both inland and coastal desalination plants. Zero-liquid discharge (ZLD) can be accomplished by using additional stages of RO, which can recycle that brine water, but the key challenge is the high concentration of divalent salts. These divalent salts (especially calcium and magnesium salts) forms a scaling layer on the RO membrane surfaces and hence shorten the life-time of the membranes. In this study, the nanofiltration (N… Show more
“…Therefore, the bigger size of ions (i.e., multivalent ions) difficulty penetrate on the membrane. Thus, the SR of NaCl < MgCl 2 < MgSO 4 could be explained by all these justifications 40 , 41 . Figure 8 The SR in PC 1.5 PP samples.…”
The membrane modules of the water treatment system are faced costly damages; thereby executing pre-desalination units based on Nanofiltration (NF) could prevent these suffers, and improve the permeated water flux (PWF) and salt rejection (SR). Hence, we focused on the construction of a novel ternary-layer NF membrane through “electrospinning Polyvinylidene Fluoride (PVDF) (as bottom layer)”, “generating middle layer by electrospinning PVDF along with, the implementation cross-linking after electrospraying Sodium Alginate”, and “synthesizing Polyamide (as top layer) through interfacial polymerization”. More importantly, it anticipated that the Taguchi statistical method can expeditiously optimize the effects of Graphene Oxide nano-sheets (GOns) on water-dependent properties, such as PWF and SR. Astonishingly, the desalination capabilities significantly improved, when the top, middle, and bottom layers simultaneously had 1, 0.1, and 0.1 wt.% of GOns, respectively. Overall, comparing the performances between the optimized sample containing low-dosage and without GOns demonstrated the PWF ameliorated from 6.68 to 20.36 L/m2 h; also, the SR ability remained on an incremental basis as NaCl < MgCl2 < MgSO4 under 6 bar pressure. Manifestly, these authentic results denoted promising, innovative, and large-scaling insights when effectual PWF and SR be necessary.
“…Therefore, the bigger size of ions (i.e., multivalent ions) difficulty penetrate on the membrane. Thus, the SR of NaCl < MgCl 2 < MgSO 4 could be explained by all these justifications 40 , 41 . Figure 8 The SR in PC 1.5 PP samples.…”
The membrane modules of the water treatment system are faced costly damages; thereby executing pre-desalination units based on Nanofiltration (NF) could prevent these suffers, and improve the permeated water flux (PWF) and salt rejection (SR). Hence, we focused on the construction of a novel ternary-layer NF membrane through “electrospinning Polyvinylidene Fluoride (PVDF) (as bottom layer)”, “generating middle layer by electrospinning PVDF along with, the implementation cross-linking after electrospraying Sodium Alginate”, and “synthesizing Polyamide (as top layer) through interfacial polymerization”. More importantly, it anticipated that the Taguchi statistical method can expeditiously optimize the effects of Graphene Oxide nano-sheets (GOns) on water-dependent properties, such as PWF and SR. Astonishingly, the desalination capabilities significantly improved, when the top, middle, and bottom layers simultaneously had 1, 0.1, and 0.1 wt.% of GOns, respectively. Overall, comparing the performances between the optimized sample containing low-dosage and without GOns demonstrated the PWF ameliorated from 6.68 to 20.36 L/m2 h; also, the SR ability remained on an incremental basis as NaCl < MgCl2 < MgSO4 under 6 bar pressure. Manifestly, these authentic results denoted promising, innovative, and large-scaling insights when effectual PWF and SR be necessary.
“…Therefore, the studies suggested that the evaporation ponds serve as the viable means for saline wastewater management if complied with mitigation standards of environmental risks such as reduced footprints and contamination of underlying potable water aquifers by infiltration. In such cases, the impermeable liners of clay or plastic membranes are a major prerequisite for designing the evaporation ponds (Ali, 2021).…”
Section: Methods Available For Disposal Of Wastewatermentioning
Different industrial activities such as agro‐food processing and manufacturing, leather manufacturing, and paper and pulp production generate highly saline wastewater. Direct discharge of saline wastewater has resulted in pollution of waterbodies by very high magnitudes. Consequently, an enormous number of pollutants such as heavy metals, salts, and organic matter are also released into the environment threatening the survival of human and biota. Saline wastewater also has significant effects on survival of plants, agricultural activities, and groundwater systems. Several treatments and disposal technologies are available for saline wastewater, but the selection of the most appropriate treatment and disposal technology still remains a major challenge with respect to the economic or technical constraints. Considering the sustainable management of saline wastewater, the present review is an attempt to compile the existing and emerging technologies for the treatment of saline wastewater. Among all the individual and hybrid technologies, land‐based treatment systems are proven to be the most efficient technologies considering the energy demands, economic, and treatment efficiencies. Likewise, new and sustainable technologies are the need of hour integrating both the treatment and management and the resource recovery factors along with the ultimate goal of the protection in terms of human health and environmental aspect.
Practitioner points
Physico‐chemical treatment technologies for saline wastewater.
Combined/Hybrid technologies for the treatment of saline wastewater.
Land‐based treatments as the environment friendly and sustainable method for saline wastewater treatment and disposal.
Role of phytoremediation in land‐based treatment.
“…Furthermore, the properties of NF membrane have high removal efficiency for divalent ions (e.g., calcium and tin) but poor rejection of monovalent ions [ 20 ]. NF membrane has other advantages, such as simplicity, durability, energy efficiency, and impurity removal [ 21 ]. NF membrane is also known for its high permeability, which is crucial for reducing energy consumption in water and wastewater treatment.…”
The toxicity of heavy metals can cause water pollution and has harmful effects on human health and the environment. Various methods are used to overcome this pressing issue and each method has its own advantages and disadvantages. Membrane filtration technology such as nanofiltration (NF) produces high quality water and has a very small footprint, which results in lower energy usage. Nanofiltration is a membrane-based separation technique based on the reverse osmosis separation process developed in the 1980s. NF membranes have a pore size of 1 nm and molecular weight cut off (MWCO) of 300 to 500 Da. The properties of NF membranes are unique since the surface charge of the membranes is dependent on the functional groups of the membrane. The rejection mechanism of NF membrane is unique as it is a combination of various rejection mechanisms such as steric hindrance, electric exclusion, dielectric effect, and hydration mechanism. However, these mechanisms have not been studied in-depth due to their complexity. There are also many factors contributing to the rejection of NF membrane. Many junior researchers would face difficulty in studying NF membrane. Therefore, this paper is designed for researchers new to the field, and will briefly review the rejection mechanisms of NF membrane by both sieving and non-sieving separation processes. This mini-review aims to provide new researchers with a general understanding of the concept of the separation process of charged membranes.
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