Industrial Effluents Research Articles

Exploring the potential of anti-bacterial and conductive ZnO–Al2O3/SPES proton exchange membrane applied in MFC for sustainable energy generation and sugar beet industry effluent treatment

This research introduces a novel approach wherein a sulfonated polyethersulfone (SPES) membrane is modified using bio-synthesized ZnO–Al2O3 nanoparticles (ZANPs). This modified membrane serves as a proton exchange membrane (PEM) within a dual-chamber microbial fuel cell (MFC) for energy production and sugar beet industry effluent treatment. We fabricated ZANPs/SPES membranes through a phase inversion process, varying the ZANPs loadings from 0.5 to 4.0 wt%. The ZANPs underwent analysis using a range of methods, including FTIR, EDS, SEM, and XRD, and the PEMs were thoroughly studied through several analyses, such as FTIR, SEM, EDS, AFM, water contact angle, water uptake, zeta potential, oxygen permeability, ion exchange capacity, proton conductivity, COD removal, coulombic efficiency, and anti-bacterial efficiency. According to the findings, ZANPs exhibited significant benefits for modified PEMs, such as improved proton conductivity, ion exchange capacity, and anti-bacterial capability. The MFC utilizing PEM with 4.0 wt% of ZANPs (ZANPs4.0/SPES) demonstrated a peak power output of 142.75 mW/m2 and a maximum current of 413 mA/m2. The values observed were notably elevated compared to the MFC that used commercial Nafion 117. The ZANPs4.0/SPES also had a maximum ion exchange capacity of 2.75 meq/g and 3.91 mS/cm proton conductivity among the fabricated PEMs compared to Nafion117, which only had 1.07 mS/cm proton conductivity and ion exchange capacity of 0.89 meq/g. Modified membranes improved COD removal from sugar beet industry effluent by up to 98.22 % and had a higher coulombic efficiency of up to 39.26 %. The anti-bacterial efficiency of ZANPs4.0/SPES was over 97 % against two types of bacteria. As per the research findings, it is confirmed that the ZANPs/SPES membranes can function efficiently in dual-chamber MFCs.

Development of a surfactant-assisted lanthanum anchored hydroxyapatite@polyaniline hybrid composite for the elimination of chromium ions from aqueous solution

The predominant cause of the global clean water deficit is water contamination caused by heavy metals discharged from various industrial effluents. Innovating low-cost adsorbents that can eliminate heavy metals from polluted water is essential to address this challenge. Human health can be negatively impacted by water contamination caused by the increased levels of carcinogenic heavy metals, such as chromium (Cr), found in wastewater. The main goal of this research is to remove chromium ions from an aqueous environment by utilizing the surfactant-assisted lanthanum anchored hydroxyapatite@polyaniline (CTAB-LaHAp@PANI) hybrid composite. Various analytical techniques including FTIR, XRD, SEM, EDX, TEM, TGA, and XPS analysis were utilized for the characterization of the prepared adsorbents. Different influencing factors such as contact time, solution pH, adsorbent dosage, and initial chromium concentration were systematically optimized through the batch method to achieve maximum removal efficiency of the CTAB-LaHAp@PANI hybrid composite. Remarkably, the CTAB-LaHAp@PANI demonstrated a maximal adsorption capacity of 98.2 mg/g, with an optimal contact time of 120 min at pH 3. The isotherm and kinetic analyses indicated that chromium adsorption onto the CTAB-LaHAp@PANI hybrid composite followed the Langmuir and pseudo-second-order kinetic models, supported by high correlation coefficient values. Moreover, the possible removal mechanism of chromium ions on the prepared hybrid composite was explained based on the results obtained from various analytical techniques. The as-prepared CTAB-LaHAp@PANI hybrid composite demonstrates a superior adsorption capacity, exceptional water stability, cost-effectiveness, and various other characteristics that render it an attractive choice for removing chromium ions from the aqueous phase.

Exploring Ficus religiosa inflorescence powder as an eco-friendly and sustainable solution for the removal of crystal violet with a disposal solution.

This study investigates the potential of using Ficus religiosa inflorescence (peepal tree) as an efficient solution for removing crystal violet from simulated and industrial wastewater. Various analyses were conducted to understand the adsorbent's structure, including particle morphology, BET surface area, FTIR, and pHZPC. The adsorption process was studied under different physicochemical factors such as temperature, concentration, contact time, and pH. Results revealed rapid adsorption, with 94.15% removal efficiency within the first 15min at neutral pH. The highest observed adsorption capacity was 198.03mgg-1, following pseudo-second-order kinetics (R2 = 0.99), indicating chemisorption. The Langmuir model accurately described the adsorption pathway (R2 = 0.99), showing monolayer adsorption. Thermodynamic analysis indicated an exothermic, feasible, and spontaneous process with increased entropy. The adsorbent could be easily regenerated using a 1:1 MeOH/H2O mixture for up to three cycles, yielding up to 73.86%. Real-time application with industrial effluent containing crystal violet showed up to 44.70% adsorption. The experiments demonstrated reliability with evaluated standard deviations (0.017935-0.000577) and relative standard deviations (0.439-0.673%), confirming statistical reliability. In conclusion, it presents a sustainable and eco-friendly approach for removing crystal violet dye from diverse wastewater sources.

A Systematic Literature Review for Addressing Microplastic Fibre Pollution: Urgency and Opportunities

Microplastic fibre (MPF) pollution is a pressing concern that demands urgent attention. These tiny synthetic textile fibres can be found in various ecosystems, including water and air, and pose significant environmental risks. Despite their size (less than 5 mm), they can harm aquatic and terrestrial organisms and human health. Studies have demonstrated that these imperceptible pollutants can contaminate marine environments, thereby putting marine life at risk through ingestion and entanglement. Additionally, microplastic fibres can absorb toxins from the surrounding water, heightening their danger when consumed by aquatic organisms. Traces of MPFs have been identified in human food chains and organs. To effectively combat MPF pollution, it is crucial to understand how these fibres enter ecosystems and their sources. Primary sources include domestic laundry, where synthetic textile fibres are released into wastewater during washing. Other significant sources include industrial effluents, breakdown of plastic materials, and atmospheric deposition. Additionally, MPFs can be directly released into the environment by improperly disposing of consumer products containing these fibres, such as non-woven hygienic products. A comprehensive approach is necessary to address this pressing issue, including understanding the sources, pathways, and potential risks of MPFs. Immediate action is required to manage contamination and mitigate MPF pollution. This review paper provides a systematic literature analysis to help stakeholders prioritise efforts towards reducing MPFs. The key knowledge gaps identified include a lack of information regarding non-standardised test methodology and reporting units, and a lack of information on manufacturing processes and products, to increase understanding of life cycle impacts and real hotspots. Stakeholders urgently need collaborative efforts to address the systematic changes required to tackle this issue and address the proposed opportunities, including targeted government interventions and viable strategies for the industry sector to lead action.

Occurrence and potential ecological risks of PFAS in Pampulha Lake, Brazil, a UNESCO world heritage site

Per- and polyfluoroalkyl substances (PFAS) comprise >4000 synthetic substances used in industrial applications and consumer products. PFAS used daily in households and manufacturing plants end up in domestic sewage, and industrial effluents can be discharged to surface water. Urban watersheds located in low and middle-income countries (LMIC), which lack sanitation infrastructure, are potential recipients of waste containing PFAS. Yet, only a few studies report PFAS occurrence in urban reservoirs and lakes, especially those located in the Global South due to resource limitations. This is the first study aimed to assess PFAS occurrence and ecological risks in Pampulha Lake, Brazil, a site which represents the reality of many other urban watersheds in LMIC as it is surrounded by densely populated areas and manufacturing plants. Surface water samples were collected monthly for 1 year from four sampling points at Pampulha Lake. Sample analysis was based on US Environmental Protection Agency Method 1633, which employs solid phase extraction followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Species sensitivity distribution (SSD) curves were built to identify potentially susceptible species based on detected water concentrations. Bioaccumulation was estimated for fish tissue. Short-chain (perfluorobutanesulfonic acid, PFBS and perfluorohexanoic acid, PFHxA) and long-chain PFAS (perfluorodecanoic acid, PFDA; perfluorooctanoic acid, PFOA; perfluorododecanoic acid, PFDoA; and perfluorooctanesulfonic acid, PFOS) were detected at the μg L−1 range. Total PFAS concentrations in the wet season were generally higher than in the dry season, likely due to limited capacity of the treatment plant processing water from tributaries which receive raw sewage. More than 5 % of aquatic species are potentially susceptible to chronic effects of PFOS at detected concentrations (0.2–2.2 μg L−1). Predicted bioaccumulation of PFOS in fish was above advisory diet intake levels for humans. Results emphasize the need for studies related to PFAS occurrence in watersheds located in LMIC.

Deciphering Indigenous Bacterial Diversity of Co-Polluted Sites to Unravel Its Bioremediation Potential: A Metagenomic Approach.

Polluted drains across the globe are affected due to reckless disposal of untreated industrial effluents resulting in significant water pollution affecting microbial community structure/dynamics. To elucidate this, polluted samples were collected from Budha Nala (BN) drain, Tung Dhab (TD) drain, and wastewater treatment plant (WWTP) receiving an inflow of organic pollutants as well as heavy metals due to anthropogenic activities. The sample of unpolluted pristine soil (PS) was used as control, as there is no history of usage of organic chemicals at this site. The bacterial diversity of these samples was sequenced using the Illumina MiSeq platform by amplifying the V3/V4 region of 16S rRNA. The majority of operational taxonomic unit (OTUs) at polluted sites belonged to phyla Proteobacteria specifically Gammaproteobacteria class, followed by Actinobacteria, Bacteriodetes, Chloroflexi, Firmicutes, Planctomycetes, WS6, and TM7, whereas unpolluted site revealed the prevalence of Proteobacteria followed by Actinobacteria, Planctomycetes, Firmicutes, Acidobacteria, Chloroflexi, Bacteroidetes, Verrucomicrobia, and Nitrospirae. The data sets decode unclassified species of the phyla Proteobacteria, Bacteriodetes, Chloroflexi, Firmicutes, and WS6, along with some unclassified bacterial species. The study provided a comparative study of changed microbial community structure, their possible functions across diverse geographical locations, and identifying specific bacterial genera as pollution bio-indicators of aged polluted drains.

Sustainable removal of methylene blue dye from textile effluents by magnetized Tea waste and Peanut shells

Methylene blue finds numerous applications across various industries but its prolonged exposure to living organisms can result in significant health risks. In this study, the adsorption of magnetized Peanut shells and Tea waste for methylene blue dye removal has been reported. The biosorbents were synthesized by co-precipitation method and their suitability for methylene blue adsorption was confirmed through characterization techniques including Scanning Electron Microscope, Fourier Transfer Infrared Spectroscopy and X-Ray Diffraction analysis. After optimizing for pH (8.0), temperature (312 k), biosorbents dosage 25 mg/L with contact periods (35 min for Tea waste@Fe3O4 and 40 min for Peanut shells@Fe3O4), and initial methylene blue concentrations (5 ppm), the removal percentages of 95.88 % for Tea waste@Fe3O4 and 84.11 % for Peanut shells@Fe3O4 were achieved effectively. The equilibrium data for MB dye adsorption fitted well with the Langmuir model (R2 = 0.99) for Tea waste@Fe3O4 which indicated the formation of monolayer formation of adsorbate at the surface of adsorbent and the Freundlich model (R2 = 0.98) for Peanut shells@Fe3O4 confirmed the multilayers formation of MB dye at the material surface. Kinetic studies specified that both Tea waste@Fe3O4 (R2 = 0.99) and Peanut shells@Fe3O4 (R2 = 0.99) followed the pseudo-second order. Thermodynamic analysis showed that the adsorption process on Tea waste@Fe3O4 and Peanut shells@Fe3O4 was spontaneous (−ΔG) and endothermic. Tea waste@Fe3O4 exhibited ΔH (27.97 kJ/mol) and entropy ΔS (93.69 kJ/mol) while ΔH = 208.9 kJ/mol and ΔS 62 kJ/mol were found for Peanut shells@Fe3O4. The performance of the proposed biosorbent in industrial effluent demonstrated their effectiveness, highlighting their potential as a cost effective and sustainable solution for wastewater treatment.

Removal of brilliant blue and direct black-19 dyes from aqueous solutions using walnut husk-derived Fe–Cu bimetallic nanoparticles embedded in multiwalled carbon nanotubes

In present study aqueous extract of walnut husk was used for the simple, cost-effective synthesis of multiwalled carbon nanotubes (MWCNT) embedded with bimetallic iron-copper (Fe–Cu) nanoparticles, which exhibits adsorption capacity of 769.23 mg/g and 804.50 mg/g for Brilliant Blue (BB) dye and Direct Black (DB-19) dye respectively. The MWCNT@Fe–Cu were characterized by using FTIR, BET, FESEM, EDX, and XRD. The adsorption experiments were conducted by varying concentrations (50 ppm–200 ppm), pH (2.0–11.0), contact time (1 min–5 min), and temperature (30 °C–60 °C) to investigate their effect on adsorption. The adsorption data was best fit with the pseudo-second-order kinetics and Langmuir isotherm model, adsorption process was endothermic and spontaneous. The adsorption of each dye up to the 5th adsorption/desorption cycle was >95 %. From the 6th cycle to the 20th cycle the adsorption decreased from 97 % to 60.98 % and 95 % to56.76 % in the case of BB dye and DB-19 dye respectively. The unique feature of adsorbent is its pH independence as it showed more than 90 % removal efficiency in acidic as well basic medium. All findings underscore the effectiveness of synthesized MWCNT@Fe–Cu to be used as a potential adsorbent for organic dyes removal from industrial effluent.

An investigation of the Excitation Wavelength-Dependent Dynamic Changes in the Mechanism of Detection of Picric Acid using Pyrene-Based Donor-Acceptor Systems.

Picric acid (PA) is an important industrial feedstock and hence the release of industrial effluents without proper remediation results in its buildup in soil and water bodies. The adverse effects of PA accumulation in living beings necessitate the development of efficient methods for its detection and quantification. Herein, we describe pyrene-based fluorescent sensors for PA, where pyrene is appended with electron-withdrawing groups, malononitrile, and 2-(3-cyano-4,5,5-trimethylfuran-2(5H)-ylidene) malononitrile (DCDHF). These molecules displayed the typical emission of pyrene monomers, as well as a broad red-shifted emission resulting from an intramolecular charge transfer (ICT) in the excited state. Both the emissions displayed a turn-off response to PA with high selectivity and sensitivity and the lowest limit of detection was estimated as 27 nM. To prove the feasibility of on-site detection, test paper strips were prepared, which could detect PA up to 4.58 picograms. Using a combination of experimental and theoretical studies the mechanism of the detection was identified as primary/secondary inner filter effect, oxidative photoinduced electron transfer, or a combination of both depending on the excitation wavelength. Interestingly, the contribution of each of these mechanisms to the total quenching process varied with a change in the excitation wavelength.

Monitoring dynamics of biocrust rehabilitation in acid-saturated desert soils

The study explores the aftermath of a wastewater reservoir failure in a phosphate fertilizer industry, resulting in the release of acidic water containing phosphorus and sulfate compounds into the Ashalim stream’s Nature Reserve in the Judean desert, which affected the soil surface biological crusts (biocrusts) layer. The study aims to examine contamination effects on biocrusts over 3 years at two research sites along the stream, compare effects between contaminated sites, assess rehabilitation treatments, and examine their impact on soil characteristics. Hypotheses suggest significant damage to biocrusts due to acidic water flow, requiring human intervention for accelerated restoration. The results indicate adverse effects on biocrust properties, risking its key role in the desert ecosystem. The biocrust layer covering the stream’s ground surface suffered significant physical, chemical, and biological damage due to exposure to industrial process effluents. However, soil enrichment treatments, including biocrust components and organic material, show promising effects on biocrust recovery.

Physicochemical study of opium industry effluent and toxicity prediction using in silico method

Physicochemical study of opium industry effluent and toxicity prediction using in silico method

Synthesis of Responsive Membranes for Water Recovery through Desalination of Saline Industrial Effluents

Polysulfone (PSF) and smart polymers (SRPs)—including polyacrylic acid (AAc), poly N-isopropylacrylamide (NIPA), and sulfonated poly(1,4-phenylene ether-ether-sulfone) (SPEES)—were used in the synthesis of responsive membranes (PSF-SRP) for application in sustainable desalination processes involving food industry effluents for water recovery and recycling. With the inclusion of SRPs, PSF-SRP membranes showed different characteristics when compared to the PSF membrane. AAc caused fibers to occur in the surface structure, increasing the MWCO of the PSF membrane, whereas NIPA and SPEES diminished the MWCO, resulting in ultrafiltration and nanofiltration membranes. Furthermore, NIPA and SPEES provided high mechanical and thermal resistance when incorporated into the PSF membrane. The performance of the membranes also showed important changes. In comparison with only PSF, PSF-SPEES and PSF-NIPA increased the water flux and salt rejection percentage by 20–30%. In addition, the highest membrane fouling resistance was observed with PSF-NIPA, while PSF-AAc and PSF-NIPA-AAc presented the lowest resistances. Therefore, PSF-NIPA and PSF-SPEES resulted in membrane improvement, including stimuli-responsive properties, allowing for effective saline effluent treatment.

Enhanced photodegradation of textile dye wastewater using silane/polymer doped ZnO nanocomposites and antibacterial activity

Accumulation of textile dye wastewater is major global issue that causes negative impact to the ecosystem. This study focuses on industrial textile dye effluent treatment by photodegradation, and degradation of Malachite green dye under sunlight, visible and UV light. ZnO demonstrated hexagonal wurtzite structure with average crystallite size 38 nm for ZnO/PEG, 21 nm for ZnO/PEG/VTES and 17 nm for ZnO/PEG/VTMS. Field Emission Scanning Electron Microscopy and Energy Dispersive Spectroscopy revealed nanometer sized particles and purity. Bandgap energy and particle size of ZnO/PEG/VTMS is 102 nm and 3.134 eV is lesser than ZnO/PEG (147 nm, 3.181 eV) and ZnO/PEG/VTES (109 nm, 3.151 eV). Photoluminescence analysis revealed reduced recombination rate of ZnO/PEG/VTMS. Antibacterial efficacy of ZnO/PEG/VTMS was tested against Staphylococcus aureus (35 mm) and Escherichia coli (29 mm). Photodegradation of textile dye wastewater by ZnO/PEG/VTMS under visible and UV light exposure revealed an effective way for textile dye effluent treatment, which maintained its efficiency even after five photodegradation cycles.

Chemistry of zeolites and zeolite based composite membranes as a cutting-edge candidate for removal of organic dyes & heavy metal ions: Progress and future directions

The quality of water has become a serious concern due to excessive industrial effluent production and poor wastewater treatment. Membrane technology has received immense attention due to its mild operating conditions, and highly efficient process. Polymer-based membranes are generally applied in various separation operations for their highly reproducible fabrication and low-cost approaches. Fouling aspects and the trade-off between selectivity and permeability are the main disadvantages of polymeric membranes. In this regard, zeolites are an attractive and promising candidate with 3D crystalline microporous systems, large and medium-pore molecular sieves, low-cost, and due to their distinct framework, are considered potential ceramic membranes for water treatment. Incorporating inorganic zeolite particles into the polymer matrix improves permeability while maintaining selectivity, and promotes mechanical strength in challenging environments and fouling conditions. Zeolite-based composite membranes can remove heavy metals and dye effluents from the aqueous medium thanks to their high adsorption capability and well-defined pore size. In this review, we focused on the significance of membranes in water treatment, structural/chemical features of zeolite-based membranes, and their design. The various strategies involved in integrating zeolites to obtain composite based membranes, an overview of toxicity issues of dyes, and heavy metals followed by an exploration of zeolite based composite membranes for the treatment of various dyes and heavy metal pollutants. Also, we tried to provide a cost analysis of zeolite-based membranes followed by commercial and industrial outlooks. Lastly, conclusion and future perspectives are drawn for the zeolite-based composite membranes.

Innovative ceramic membrane plate filtration system for sustainable semiconductor industry wastewater treatment: A pilot scale study

Conventional methods of coagulation and flocculation are used to treat semiconductor industry wastewater, but they often fail to recover valuable silica particles and result in resource wastage and environmental risks. Despite the potential of membrane filtration for silica recovery, limited research is available on scaling up the process beyond laboratory scale. Therefore, this study aims to develop and evaluate the feasibility of pilot-scale ceramic membrane plate filtration system for treatment of diluted back grinding wastewater (DBGW) from the semiconductor industry. Specific objectives include assessing permeate quality in terms of rejection and benchmarking it to established standards, identifying fouling mechanisms, characterising sludge constituents and conducting life cycle assessment (LCA) to evaluate the environmental impacts of the ceramic membrane plate filtration system compared with conventional treatment. The pilot membrane plate filtration system demonstrated significant reductions of 85.71 % in chemical oxygen demand, 67.31 % in total suspended solid, 75 % in nitrate–nitrogen (NO3-N), 33.33 % in ammonia nitrogen (NH3-N), 74.07 % in colour and 98.37 % in turbidity. Effective mitigation of irreversible fouling during DBGW filtration was achieved using 0.1 M NaOCl, resulting in a flux recovery ratio of 95.35 %. The retained silica on the membrane exhibited a purity of 64 wt%, as confirmed by EDX analysis. The treated wastewater met various regulatory standards including Malaysia Industrial Effluent Discharge (Standard A and Standard B), restricted USEPA standard, NWQS Class IIA, IIB, III, IV and V, and Singapore’s greywater standards. The fouling mechanism of silica on the ceramic membrane was well represented by the standard blocking model with an R2 value of 0.92. Furthermore, LCA confirmed that the utilisation of the ceramic membrane plate filtration system exhibited fewer environmental impacts than conventional coagulation–flocculation methods. This study represents a significant breakthrough in wastewater treatment in the semiconductor industry in terms of concurrent recovery and reuse of silica to address environmental and resource sustainability concerns.

Distribution and Comprehensive Risk Evaluation of Cr, Cd, Fe, Zn, and Pb from Al Lith Coastal Seawater, Saudi Arabia

Seawater contamination is a global challenge due to its hazardous effects on marine organisms and human health. Twenty-three surface seawater samples were collected from the Al Lith intertidal area along the Saudi Red Sea coast to evaluate the ecological risks and document the potential sources of Cr, Cd, Fe, Zn, and Pb. Contamination factor (CF), contamination degree (Cd), water quality index (WQI), and heavy metal pollution index (HPI), as well as multivariate tools were applied. The average concentrations of HMs (μg/L) had the following order: Zn (6.616) > Pb (0.284) > Cd and Cr (0.268) > Fe (0.197). CF results showed moderate contamination of seawater with Cd and low contamination of Cr, Fe, Zn, and Pb. However, 26.09% of the samples showed considerable contamination with Cd. Average Cd values revealed low contamination with HMs, while 17.39% of the samples showed moderate contamination. HPI average values indicated medium pollution of Al Lith seawater, while 13 samples reported high pollution. The higher HPI values were reported in samples characterized by higher concentrations of HMs, particularly Cd and Zn. Correlation matrix and principal component analysis suggested anthropogenic sources for Pb and Zn, mostly from industrial and agricultural effluents, landfilling, and domestic wastewater, apart from their natural sources.

Heavy metals removal from industrial wastewater of Biskra (Algeria) by Arundo donax and Phragmites australis.

Industrial effluents pose a serious environmental problem, because they contain toxic contaminants mainly heavy metals that are the most dangerous to humans, animals, plants, and the environment in general. Phytoremediation using macrophytes is an adopted technique for the environment decontamination due to its efficiency and cost-effectiveness. The present study aims to highlight the capabilities of macrophytes to remove heavy metals from wastewater of Biskra region (Algeria). The methodology consists of filling out the filters planted with Arundo donax and Phragmites australis with raw industrial wastewater, then recovering decontaminated water after 15 days to assess removal of lead, copper, zinc, and iron. Both plants had shown a good efficiency for the removal of metals loaded in wastewater eliminating about 94 to 98% of initial concentration. In addition, calculated bioaccumulation factor (BAF) had confirmed the accumulation of heavy metals in different parts of experimental plants; recorded values of BAF > 1 allowed the consideration of Arundo donax and Phragmites australis as good hyper-accumulator plants. Obtained results confirm the efficiency of phytoremediation technology using macrophytes for the wastewater treatment in particular and the environment decontamination in general.

Evaluating the Potential of Modified Mango Leaves as a Biosorbent for the Removal of Mercury (II) Ion and Congo Red from Wastewater

The discharge of harmful metallic elements from industrial byproducts has resulted in notable environmental and public health risks. The aim of this study was to investigate the effectiveness of mango leaves as a cost-effective adsorbent in eliminating Hg (II) ions from industrial effluents. Experimental procedures were carried out under controlled conditions at ambient temperature to evaluate the influence of pH, contact duration, initial metal levels, adsorbent quantity, and temperature on the adsorption mechanism. The most favorable pH for optimal Hg (II) ions adsorption was identified at pH 7. The adsorption process displayed swift kinetics in the initial 30 minutes of contact, leading to a removal rate exceeding 90%, with equilibrium achieved after 70 minutes of stirring. Analysis of kinetics revealed a significant correlation coefficient for a pseudo-second-order kinetic equation. The absorption of Hg (II) ions escalated with increased stirring intensity and decreased adsorbent amount. The interaction between Hg (II) ions, Congo red, and mango leaves was analyzed employing Langmuir, Freundlich, and BET isotherm models. The equilibrium data was best fitted by the Langmuir model, presenting a correlation coefficient of 0.98 and a maximum adsorption capacity of 28.40 mg/g. These results underscore the potential of mango leaves as an affordable bio adsorbent for addressing heavy metal pollution in wastewater.

High surface area biochar for the removal of naphthenic acids from environmental water and industrial wastewater.

This study reports the production of biochar adsorbents from two major crop residues (i.e., rice and wheat straw) to remove naphthenic acids from water. The alkali treatment approach was used for biochar activation that resulted in a tremendous increase in their surface area, i.e., up to 2252 and 2314 m2/g, respectively, for rice and wheat straw biochars. Benzoic acid was used as a model compound to optimize critical adsorption parameters. Its maximum monolayer adsorption capacity of 459.55 and 357.64mg/g was achieved for activated rice and wheat straw biochars. The adsorption of benzoic acid was exothermic (∆H° = - 7.06 and - 3.89kJ/mol) and identified possibly as physisorption (Gibbs free energy ranges 3.5-4.0kJ/mol). The kinetic study suggested that adsorption follows pseudo-second-order kinetics with qe2 for rice straw and wheat straw-derived adsorbents at 200 and 194mg/g, respectively. As adsorbent, the recyclability of activated biochars was noticed with no significant loss in their efficiency for up to ten successive regeneration cycles. The adsorption results were validated using a commercial naphthenic acid mixture-spiked river water and paper/pulp industrial effluent. The activated rice and wheat straw biochars exhibited excellent adsorption efficiency of 130.3 and 74.6mg/g, respectively. The naphthenic acid adsorption on biochar surface was due to various interactions, i.e., weak van der Waal's, pore filling, π-π stacking, and ionic interactions. This study offers a cost-effective and eco-friendly approach to valorizing agricultural residues for pollutant removal from industrial wastewater, including petroleum refineries.

Mapping and assessment of groundwater pollution risks in the main aquifer of the Mostaganem plateau (Northwest Algeria): utilizing the novel vulnerability index and decision tree model.

Water plays a pivotal role in socio-economic development in Algeria. However, the overexploitations of groundwater resources, water scarcity, and the proliferation of pollution sources (including industrial and urban effluents, untreated landfills, and chemical fertilizers, etc.) have resulted in substantial groundwater contamination. Preserving water irrigation quality has thus become a primary priority, capturing the attention of both scientists and local authorities. The current study introduces an innovative method to mapping contamination risks, integrating vulnerability assessments, land use patterns (as a sources of pollution), and groundwater overexploitation (represented by the waterhole density) through the implementation of a decision tree model. The resulting risk map illustrates the probability of contamination occurrence in the substantial aquifer on the plateau of Mostaganem. An agricultural region characterized by the intensive nutrients and pesticides use, the significant presence of septic tanks, widespread illegal dumping, and a technical landfill not compliant with environmental standards. The critical situation in the region is exacerbated by excessive groundwater pumping surpassing the aquifer's natural replenishment capacity (with 115 boreholes and 6345 operational wells), especially in a semi-arid climate featuring limited water resources and frequent drought. Vulnerability was evaluated using the DRFTID method, a derivative of the DRASTIC model, considering parameters such as depth to groundwater, recharge, fracture density, slope, nature of the unsaturated zone, and the drainage density. All these parameters are combined with analyses of inter-parameter relationship effects. The results show a spatial distribution into three risk levels (low, medium, and high), with 31.5% designated as high risk, and 56% as medium risk. The validation of this mapping relies on the assessment of physicochemical analyses in samples collected between 2010 and 2020. The results indicate elevated groundwater contamination levels in samples. Chloride exceeded acceptable levels by 100%, nitrate by 71%, calcium by 50%, and sodium by 42%. These elevated concentrations impact electrical conductivity, resulting in highly mineralized water attributed to anthropogenic agricultural pollution and septic tank discharges. High-risk zones align with areas exhibiting elevated nitrate and chloride concentrations. This model, deemed satisfactory, significantly enhances the sustainable management of water resources and irrigated land across various areas. In the long term, it would be beneficial to refine "vulnerability and risk" models by integrating detailed data on land use, groundwater exploitation, and hydrogeological and hydrochemical characteristics. This approach could improve vulnerability accuracy and pollution risk maps, particularly through detailed local data availability. It is also crucial that public authorities support these initiatives by adapting them to local geographical and climatic specificities on a regional and national scale. Finally, these studies have the potential to foster sustainable development at different geographical levels.