Methods to prepare biosorbents and magnetic sorbents for water treatment: a review

Access to drinkable water is becoming more and more challenging due to worldwide pollution and the cost of water treatments. Water and wastewater treatment by adsorption on solid materials is usually cheap and effective in removing contaminants, yet classical adsorbents are not sustainable because they are derived from fossil fuels, and they can induce secondary pollution. Therefore, biological sorbents made of modern biomass are increasingly studied as promising alternatives. Indeed, such biosorbents utilize biological waste that would otherwise pollute water systems, and they promote the circular economy. Here we review biosorbents, magnetic sorbents, and other cost-effective sorbents with emphasis on preparation methods, adsorbents types, adsorption mechanisms, and regeneration of spent adsorbents. Biosorbents are prepared from a wide range of materials, including wood, bacteria, algae, herbaceous materials, agricultural waste, and animal waste. Commonly removed contaminants comprise dyes, heavy metals, radionuclides, pharmaceuticals, and personal care products. Preparation methods include coprecipitation, thermal decomposition, microwave irradiation, chemical reduction, micro-emulsion, and arc discharge. Adsorbents can be classified into activated carbon, biochar, lignocellulosic waste, clays, zeolites, peat, and humic soils. We detail adsorption isotherms and kinetics. Regeneration methods comprise thermal and chemical regeneration and supercritical fluid desorption. We also discuss exhausted adsorbent management and disposal. We found that agro-waste biosorbents can remove up to 68–100% of dyes, while wooden, herbaceous, bacterial, and marine-based biosorbents can remove up to 55–99% of heavy metals. Animal waste-based biosorbents can remove 1–99% of heavy metals. The average removal efficiency of modified biosorbents is around 90–95%, but some treatments, such as cross-linked beads, may negatively affect their efficiency.

     

Application of sludge-based carbonaceous materials in a hybrid water treatment process based on adsorption and catalytic wet air oxidation

This paper describes a preliminary evaluation of the performance of carbonaceous materials prepared from sewage sludges (SBCMs) in a hybrid water treatment process based on adsorption and catalytic wet air oxidation; phenol was used as the model pollutant. Three different sewage sludges were treated by either carbonisation or steam activation, and the physico-chemical properties of the resultant carbonaceous materials (e.g. hardness, BET surface area, ash and elemental content, surface chemistry) were evaluated and compared with a commercial reference activated carbon (PICA F22). The adsorption capacity for phenol of the SBCMs was greater than suggested by their BET surface area, but less than F22; a steam activated, dewatered raw sludge (SA_DRAW) had the greatest adsorption capacity of the SBCMs in the investigated range of concentrations (<0.05 mol L^?1). In batch oxidation tests, the SBCMs demonstrated catalytic behaviour arising from their substrate adsorptivity and metal content. Recycling of SA_DRAW in successive oxidations led to significant structural attrition and a hardened SA_DRAW was evaluated, but found to be unsatisfactory during the oxidation step. In a combined adsorption–oxidation sequence, both the PICA carbon and a selected SBCM showed deterioration in phenol adsorption after oxidative regeneration, but a steady state performance was reached after 2 or 3 cycles.     

Steady state of semi-continuous anaerobic digestion of cattle manure under the stress of adding iron and titanium oxide nanoparticles

Journal of Material Cycles and Waste Management - Anaerobic digestion (AD) is a sustainable technology that combines biogas production with proper waste management. However, the operation of an...     

Trace elements exposure influences proximate body composition and antioxidant enzyme activities of the species tilapia and catfish in Burullus Lake—Egypt: human risk assessment for the consumers

The trace elements concentration in the fish estimates the contamination degree in the aquatic environment. These toxic trace elements are transported into the human through the consumption of polluted fish. This study estimated the effect of Cd, Hg, Pb, As, and Al on tilapia species and catfish Clarias gariepinus (six for each species of fish) inhabiting Burullus Lake—Egypt 30° 33′–31° 08′ E and 30° 22′–31° 35′ N. The highest Pb concentrations recorded in the muscle of C. gariepinus 2.29 ± 0.29 μg/g while S. galilaeus was estimated the lowest Hg concentration of 0.54 ± 0.02 μg/g which indicated the presence of contaminants exceeded the limits permitted by FAO/WHO and EC. The maximum mean carbohydrate, lipid, and protein recorded in O. niloticus 18.66, 16.33, and 58.16 mg/g, respectively; moisture in O. aureus 67.33%; and ash 16.41% in O. niloticus. The lowest amount of carbohydrate was recorded in the T. zillii 14.1 mg/g, lipid, and ash in C. gariepinus 11.65 mg/g and 3.375%, respectively. Protein and moisture in the S. galilaeus were 53.75 mg/g and 60.75%, respectively. The results recorded a marked insignificant (P > 0.05) decrease in CAT, GR, and GPx activity in O. niloticus. GSH and SOD activity was an insignificant (P > 0.05) decrease in C. gariepinus. The results concluded that the trace elements concentrations exceed the maximum permissible limits recommended in fish samples set by Egypt, FAO, WHO, and EC. The estimated weekly intake of all elements through consumption of studied fish species inhabiting Burullus Lake by a child (15 kg) in Egypt is well above the PTWI recommended by FAO/WHO, whereas it is well below the PTWI for human consumption by young people (40 kg) and adult person (70 kg), at least in respect of residual levels of studied elements excluding Cd and Hg. Thus, for consumer protection, these fish species are unsafe and have hazardous effects for children, and about youth and adult consumption, caution must be taken to consider individuals eating significant amounts of fish.

     

Post-irradiation physicochemical features of polymer composite for the removal of Co(II) and Nd(III) from aqueous solutions

Environmental Science and Pollution Research - The scientific impact of this work is the protection of the environment from hazardous pollutants. Gamma irradiation was employed for the preparation...     

Biofuel production,hydrogen production and water remediation by photocatalysis,biocatalysis and electrocatalysis

The energy crisis and environmental pollution have recently fostered research on efficient methods such as environmental catalysis to produce biofuel and to clean water. Environmental catalysis refers to green catalysts used to breakdown pollutants or produce chemicals without generating undesirable by-products. For example, catalysts derived from waste or inexpensive materials are promising for the circular economy. Here we review environmental photocatalysis, biocatalysis, and electrocatalysis, with focus on catalyst synthesis, structure, and applications. Common catalysts include biomass-derived materials, metal–organic frameworks, non-noble metals nanoparticles, nanocomposites and enzymes. Structure characterization is done by Brunauer–Emmett–Teller isotherm, thermogravimetry, X-ray diffraction and photoelectron spectroscopy. We found that water pollutants can be degraded with an efficiency ranging from 71.7 to 100%, notably by heterogeneous Fenton catalysis. Photocatalysis produced dihydrogen (H₂) with generation rate higher than 100 μmol h⁻¹. Dihydrogen yields ranged from 27 to 88% by methane cracking. Biodiesel production reached 48.6 to 99%.

     

Contribution of a systemic modeling approach applied to support risk analysis of a storage unit of chemical products in Morocco

This paper proposes a new systemic modeling approach using the unified modeling language (UML) as an operational tool to model a complex industrial system and analyzes its risks. This approach is presented as a modeling process divided into three phases corresponding to functional analysis, structural analysis and risk analysis. This study aims to formalize the interactions within an industrial system and to identify the abnormal situations which could generate risks. The application of this approach is demonstrated with an example of a storage unit of chemical products located in Morocco. This approach provides a comprehensive view that facilitates the understanding of the organization of an industrial system and leads to more effective analysis of its safety.     

Development of key performance measures for the automobile green supply chain

The main purpose of this study was to develop a set of measures for evaluating the performance of the automobile green supply chain. This study reviewed various literatures on green supply chain performance measurement, environmental management, traditional supply chain performance measurement, and automobile supply chain management. In order to comprehensively and effectively establish the relevant measures, a suitable framework which considered the automobile green supply chain as a two-in-one chain was adopted. This two-in-one chain comprised a forward and backward chain for the automobile industry. Consequently, 10 measures with 49 metrics and 6 measures with 23 metrics were identified and developed for the forward and backward chains, respectively. Sequel to the development of these measures, a survey was conducted using a four-page questionnaire distributed to experts (including academics and practitioners) to establish their importance and applicability. The findings of this study suggested that the importance and applicability of all the developed measures have been substantiated. For the forward chain, the most crucial measure was customer perspective while the most applicable one was traditional supply chain cost. The reverse chain measures were topped by management commitment in terms of both importance and applicability. This study contributed to the advancement of knowledge by pioneering the development of a set of holistic measures for evaluating the performance of the automobile green supply chain. The study was wrapped up with the proposition of directions for further studies.     

Extraction of Co,Ni, Cu,Zn and Cd ions using 2-aminophenylaminopropylpolysiloxane

Insoluble porous solid functionalized ligand system bearing 2-aminophenylaminopropyl chelating ligand of the general formula P–(CH₂)₃NH–(C₆H₄)–NH₂ was prepared via the sol–gel process, where P represents [Si–O] _n polysiloxane network. First, the 2-aminophenylaminopropylsilane agent was prepared by substitution reaction between 3-chloropropyltrimethoxysilane and 1,2-phenylenediamine, followed by hydrolytic polycondensation between 2-aminophenylaminopropylsilane agent and tetraethylorthosilicate(TEOS). The immobilized 2-aminophenylaminopropylpolysiloxane P–(CH₂)₃NH–(C₆H₄)–NH₂(P–AphA) was characterized by ¹³C NMR, XPS, and FTIR. The results showed that 1,2-phenylenediamine groups were introduced onto polysiloxane network. The functionalized ligand system exhibits 90–100% metal uptake capacity for all metal ions except Cd²⁺. The elemental analysis data and the metal uptake capacities of the immobilized ligand system suggest that over than 90% ligand sites were involved in coordination with metal ions except that of cadmium forming 1:1 metal to ligand ratio complexes.     

Land use changes and its impacts on water resources in Nile Delta region using remote sensing techniques

Sustainable water resources management plans depend on reliable monitoring of land use –land cover (LULC) changes. The use of the remote sensing techniques in LULC changes detection brings consistency and reliability to the decision maker at regional scale. Three temporal data sets of images were used to obtain the land cover changes in this study: Landsat-5 Thematic Mapper (TM) acquired in 1984, and Landsat-7 enhanced Thematic Mapper acquired in 2000 and 2005 consequently. Each temporal data set consists of four Landsat scenes, which were mosaicked to cover the whole Nile Delta. Two different supervised classification algorithms were implemented to produce classification maps in thematic form. Support vector machine showed higher classification accuracies in comparison with maximum likelihood classification. The results indicated that the rapid imbalance changes occurred among three land cover classes (urban, desert, and agricultural land). These changes powered the land degradation and land fragmentation processes over the agricultural land exclusively due to urban encroachment. Slight land cover changes were detected between fish farms and surface water land cover classes.