Application of lime and calcium hypochlorite in the dephenolisation and discolouration of olive mill wastewater

The application of hypochlorite for the removal of soluble COD, phenolic and polyphenolic like compounds, and other organic compounds responsible for the olive mill wastewater (OOWW) colour has been experimentally studied. After the OOWW filtration on a sand column, the effluent was subjected to a fast liming under optimal conditions. Lime application reduced polyphenols, COD and SS contents to half of their initial values but an important blackening of the treated OOWW was observed, especially when adding high concentrations of lime (10% (W/V) and 15% (W/V)).A second stage of treatment was applied using calcium hypochlorite. In this stage, removal of the studied compounds reached as much as 95% at higher concentrations, and particularly the colouring of OOWW which is generally difficult to eliminate was greatly reduced. The OOWW hypochloration acted through coagulation–flocculation and a rapid oxidation of the organic matter proceeded from the first 5 min. The kinetic study of the degradation of the waste polluting compounds from liming showed that Ca(ClO)₂ reacts similarly in the elimination of organic compounds, polyphenols, SS and colouration. The analysis of the organochloride compounds generated by the reaction between hypochlorite and the organic compounds showed that DDD, DDT and the heptachlor contents exceeded the values recommended by the International and European drinking water standards.     

Application of polyamide thin-film composite layered on polysulfone-GO/TiO2 mixed matrix membranes for removal of nitrotoluene derivatives from petrochemical wastewaters

Release of harmful organic intermediates or byproducts during the manufacture of petrochemical compounds is a serious problem in petrochemical plants. In this work, polysulfone membranes blended with GO/TiO₂ nanocomposite were synthesized by phase inversion method and coated with a polyamide layer formed by interfacial polymerization to prepare a thin-film composite (TFC) sample. Analysis and characterization of the sample were carried out by XRD, FE-SEM, BET, FTIR/ATR, AFM, TGA, and zeta potential. Results indicated that incorporation of GO/TiO₂ into the membrane structure enhanced porosity, surface roughness, and macrovoid formation along the cross-section of the sublayer and permeability of the membrane. The TFC membranes were applied to remove mononitrotoluene (MNT) and dinitrotoluene (DNT) as the basic intermediates of toluene diisocyanate (TDI). The membranes demonstrated high efficiency (>?90%) for the removal of MNT and DNT according to the charge exclusion mechanism and Donnan effect. Application of the TFC membrane for treatment of wastewater in the TDI plant showed that the removal of pollutants is variable in the range of 45–65% and 53–69% for the membrane with the highest flux and highest rejection in different transmembrane pressure, respectively.

     

Hydrogeochemistry study and groundwater quality assessment in the north of Isfahan,Iran

This study presents the groundwater quality assessment in the north of Isfahan, Iran. In the study area, assessment and measurement of groundwater hydrochemical parameters such as pH, total dissolved solids (TDS), electrical conductivity (EC), sodium absorption ratio (SAR), total hardness, major cations (K⁺, Na⁺, Ca²⁺ and Mg²⁺) and major anions (Cl^?, \({\text{HCO}}_{ 3}^{ - } ,{\text{CO}}_{3}^{2 - }\) and \({\text{SO}}_{4}^{2 - }\)) concentrations were performed. Accordingly, the 66 water samples from different locations were collected during April and May 2015. Water samples collected in the field were analyzed in the laboratory for cations and anions using the standard methods. In this research, the analytical results of physiochemical parameters of groundwater were compared with the standard guideline values as recommended by the world health organization (WHO) for drinking and public health purposes. The pH values of groundwater samples varied from 7.05 to 8.95 with a mean of 7.78, indicating a neutral to slightly alkaline water. TDS values showed that 14% of the samples exceeds the desirable limit given by WHO. EC values varied from 213 to 4320 µS/cm, while 23% of the samples were more than the standard limit. Gibbs diagram had shown that 90% of the samples in the study area fall in the rock weathering zone, and this means that chemical weathering of rock-forming minerals is the main factor controlling the water chemistry in the study area. Irrigation suitability and risk assessment of groundwater are evaluated by measuring EC, %Na, SAR and RSC. According to the dominant cations and anions, five types of water were identified in the water samples: Ca-HCO₃, Ca-SO₄, Na-Cl, Na-HCO₃ and Na-SO₄. The results show that the majority of samples (30 samples, 45%) belongs to the mixed Na-SO₄ water type. Correlation analysis and principal component analysis was used to identify the relationship between ions and physicochemical parameters. Results indicated that 18 stations of the study area had the best quality and can be used for irrigation and drinking purposes in the future.     

ModelOps for enhanced decision-making and governance in emergency control rooms

Environment Systems and Decisions - For mission critical (MC) applications such as bushfire emergency management systems (EMS), understanding the current situation as a disaster unfolds is critical...     

The use of silica gel modified with allyl 6-methyl-4-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate for selective separation and preconcentration of lead in environmental samples

The aim of the present work is the assessment of a new sorbent, prepared using silica gel coated with a pyrimidine derivative (allyl 6-methyl-4-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate), for extraction and preconcentration trace amount of lead from different samples prior to determination by flame atomic absorption spectrometry. Common coexisting ions did not interfere with the separation and determination of lead at pH?6, so that lead ion completely adsorbed on the column. The limit of detection based on three times the standard deviation of the blank was found to be 0.53 ng?mL^?1 in original solution. Obtained sorption capacity for 1 g sorbent was 5.0 mg Pb. The linearity was maintained in the concentration range of 0.1–30.0 ng?mL^?1 for the concentrated solution. Eight replicate determinations of 2.0 μg?mL^?1 of lead in the final solution gave relative standard deviation of ±2.6 %. The proposed method was successfully applied to the determination trace amounts of lead in the environmental samples such as carrot, rice, zardchoobe, and real water samples.     

Use of plastic waste (poly-ethylene terephthalate) in asphalt concrete mixture as aggregate replacement.

One of the environmental issues in most regions of Iran is the large number of bottles made from poly-ethylene terephthalate (PET) deposited in domestic wastes and landfills. Due to the high volume of these bottles, more than 1 million m3 landfill space is needed for disposal every year. The purpose of this experimental study was to investigate the possibility of using PET waste in asphalt concrete mixes as aggregate replacement (Plastiphalt) to reduce the environmental effects of PET disposal. For this purpose the mechanical properties of plastiphalt mixes were compared with control samples. This study focused on the parameters of Marshall stability, flow, Marshall quotient (stability-to-flow ratio) and density. The waste PET used in this study was in the form of granules of about 3 mm diameter which would replace (by volume) a portion of the mineral coarse aggregates of an equal size (2.36-4.75 mm). In all prepared mixes the determined 6.6% optimum bitumen content was used. In this investigation, five different percentages of coarse aggregate replacement were used. The results showed that the aggregate replacement of 20% by volume with PET granules would result in a reduction of 2.8% in bulk compacted mix density. The value of flow in the plastiphalt mix was lower than that of the control samples. The results also showed that when PET was used as partial aggregate replacement, the corresponding Marshall stability and Marshall quotient were almost the same as for the control samples. According to most of specification requirement, these results introduce an asphalt mix that has properties that makes it suitable for practical use and furthermore, the recycling of PET for asphalt concrete roads helps alleviate an environmental problem and saves energy.     

Detection of SARS-CoV-2 in the indoor air of intensive care unit (ICU) for severe COVID-19 patients and its surroundings: considering the role of environmental conditions

Environmental Science and Pollution Research - There is ambiguity about the airborne transmission of the SARS-CoV-2. While a distance of 6 feet is considered a safe physical distance, new findings...     

Temperature-responsive graphene oxide/N-isopropylacrylamide/2-allylphenol nanocomposite for the removal of phenol and 2,4-dichlorophenol from aqueous solution

In this study, a novel thermo-responsive polymer was synthesized with efficient grafting of N-isopropylacrylamide as a thermosensitive polymer onto the graphene oxide surface for the efficient removal of phenol and 2,4-dichlorophenol from aqueous solutions. The synthesized polymer was conjugated with 2-allylphenol. Phenol and 2,4-dichlorophenol were monitored by ultra-performance liquid chromatography system equipped with a photodiode array detector. The nanoadsorbent was characterized by different techniques. The nanoadsorbent revealed high adsorption capacity where the removal percentages of 91 and 99% were found under optimal conditions for phenol and 2,4-dichlorophenol, respectively (for phenol; adsorbent dosage = 0.005 g, pH = 8, temperature= 25 °C, contact time = 60 min; for 2,4-dichlorophenol; adsorbent dosage = 0.005 g, pH = 5, temperature = 25 °C, contact time = 10 min). Adsorption of phenol and 2,4-dichlorophenol onto nanoadsorbent followed pseudo-second-order kinetic and Langmuir isotherm models, respectively. The values of ΔG (average value = ? 11.39 kJ mol^?1 for phenol and 13.42 kJ mol^?1 for 2,4-dichlorophenol), ΔH (? 431.72 J mol^?1 for phenol and ? 15,721.8 J mol^?1 for 2,4-dichlorophenol), and ΔS (35.39 J mol^?1 K^?1 for phenol and ? 7.40 J mol^?1 K^?1 for 2,4-dichlorophenol) confirmed spontaneous and exothermic adsorption. The reusability study indicated that the adsorbent can be reused in the wastewater treatment application. Thermosensitive nanoadsorbent could be used as a low-cost and efficient sorbent for phenol and 2,4-dichlorophenol removal from wastewater samples.

     

Land Use-Based Landscape Planning and Restoration in Mine Closure Areas

Landscape planning and restoration in mine closure areas is not only an inevitable choice to sustain mining areas but also an important path to maximize landscape resources and to improve ecological function in mine closure areas. The analysis of the present mine development shows that many mines are unavoidably facing closures in China. This paper analyzes the periodic impact of mining activities on landscapes and then proposes planning concepts and principles. According to the landscape characteristics in mine closure areas, this paper classifies available landscape resources in mine closure areas into the landscape for restoration, for limited restoration and for protection, and then summarizes directions for their uses. This paper establishes the framework of spatial control planning and design of landscape elements from “macro control, medium allocation and micro optimization” for the purpose of managing and using this kind of special landscape resources. Finally, this paper applies the theories and methods to a case study in Wu’an from two aspects: the construction of a sustainable land-use pattern on a large scale and the optimized allocation of typical mine landscape resources on a small scale.