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The influence of biochar on the soil structure and aggregate stability has been debated in previous studies. To probe the action of biochar on soil aggregates, a 5-year field experiment was implemented in the brown earth soil of northeastern China. We determined the aggregate distribution (> 2000 μm, 250–2000 μm, 53–250 μm, and < 53 μm) and organic carbon (OC) and organo-mineral complex contents both in the topsoil (0–20 cm) and within the soil aggregates. Three treatments were studied as follows: control (basal application of mineral NPK fertilizer), biochar (biochar applied at a rate of 2.625 t ha−1), and stover (maize stover applied at a rate of 7.5 t ha−1), and all treatments received the same fertilization. The biochar and stover applications decreased the soil bulk and particle densities significantly (p < 0.05) and enhanced the soil total porosity. Both amendments significantly (p < 0.05) enhanced the total OC, heavy OC fractions, and organo-mineral complex quantities in the bulk soil as well as in all the studied aggregate fractions. Biochar and stover applications promoted the formation of small macroaggregates. A greater amount of organic matter was contained in the macroaggregates, which led to the formation of more organo-mineral complexes, thereby improving soil aggregate stability. However, the different mechanisms underlying the effect of biochar and stover on organo-mineral complexes need further research. Biochar and stover applications are both effective methods of improving the soil structure in Northeast China. Refereed/Peer-reviewed

This chapter provides an attempt to centralize and unify information on a plethora of techniques used for the analysis of particulate plastics in soil and water. Plastic production required to meet unabating demands was reported to increase from 0.5 million tons per year in 1960 to as high as 300 million tons in 2013. Microplastics can directly enter the environment from large plastic items that are continuously fragmenting until they attain micrometric dimensions. Microplastics tend to sediment after reaching soil and aquatic systems via effluents from wastewater treatment plants. Pressurized fluid extraction is another method used for extraction of microplastics (MP), which involves a sample preparation technique that employs elevated temperatures and pressure with liquid solvents to achieve rapid and efficient extraction of the analytes from the solid matrix. A new and improved, cost-effective oil extraction protocol was demonstrated as an alternative to density-based approaches by taking advantage of the oleophilic properties of MPs.

Enhanced silicate rock weathering (ERW), deployable with croplands, has potential use for atmospheric carbon dioxide (CO2) removal (CDR), which is now necessary to mitigate anthropogenic climate change1. ERW also has possible co-benefits for improved food and soil security, and reduced ocean acidification2–4. Here we use an integrated performance modelling approach to make an initial techno-economic assessment for 2050, quantifying how CDR potential and costs vary among nations in relation to business-as-usual energy policies and policies consistent with limiting future warming to 2 degrees Celsius5. China, India, the USA and Brazil have great potential to help achieve average global CDR goals of 0.5 to 2 gigatonnes of carbon dioxide (CO2) per year with extraction costs of approximately US$80–180 per tonne of CO2. These goals and costs are robust, regardless of future energy policies. Deployment within existing croplands offers opportunities to align agriculture and climate policy. However, success will depend upon overcoming political and social inertia to develop regulatory and incentive frameworks. We discuss the challenges and opportunities of ERW deployment, including the potential for excess industrial silicate materials (basalt mine overburden, concrete, and iron and steel slag) to obviate the need for new mining, as well as uncertainties in soil weathering rates and land–ocean transfer of weathered products. A detailed assessment of the techno-economic potential of enhanced rock weathering on croplands identifies national CO2 removal potentials, costs and engineering challenges if it were to be scaled up to help meet ambitious global CO2 removal targets.

Rapid and far-reaching transitions are required to combat climate change and its impacts. Carbon capture and storage within mineral deposits is a promising solution to remove CO2 from the atmosphere. In-situ geological storage and ex-situ mineral sequestration are practically sufficient for sequestering all the anthropogenic CO2. Recent research reports that more than 95% of injected CO2 was mineralized into carbonates in two years by using in-situ geological approach, and mining wastes and secondary minerals were recycled as resources for ex-situ CO2 sequestration. However, geological activity is the major risk of in-situ storage, while high energy consumption and associated cost may limit the application of ex-situ carbonation. Significant technical breakthroughs of mineral and geological CO2 sequestration are therefore of vital importance to realize a “net-zero CO2 emissions” and even “carbon-negative” society.

The knowledge about lead (Pb) sorption on soil-derived black carbons (SBCs) under different cultivation intensities of soils is limited. In this study, chemical and spectroscopic methods were applied to investigate the Pb sorption mechanisms on SBCs in soils from a forest land, a rubber plantation area, and a vegetable farm with none, less and highly intensive cultivation, respectively, that are located in the Hainan Island of China. Results showed that the specific surface area and cation exchange capacity of the SBCs from the less and highly intensive cultivation soils were 4.5- and 2.7-fold, and 1.3- and 1.8-fold higher compared to that of SBC from the no-cultivation soil, which subsequently enhanced the Pb sorption capacities of SBCs in iron exchange fraction. Ion exchange and hydrogen bonded Pb fractions together accounted for about 80% of total Pb sorbed on all SBCs at an externally added 1000 mg L−1 Pb solution concentration. The O[dbnd]C–O groups also played key roles in Pb sorption by forming complexes of O[dbnd]C–O–Pb–O and/or O[dbnd]C–O–Pb. Overall, SBCs in soils under all studied cultivation intensities showed high potential to sorb Pb (with the maximum absorbed Pb amount of 46.0–91.3 mg g−1), and increased Pb sorption capacities of the studied soils by 18.7–21.1 mg kg−1 in the stable fraction (complexation). Therefore, SBC might be a potential environment-friendly material to enhance the Pb immobilization capacity of soil Refereed/Peer-reviewed

Refereed/Peer-reviewed Ethidium bromide (EtBr)-containing wastewater can be hazardous to biodiversity when released into the soil and water bodies without treatment. EtBr can mutate living microbial cells and pose toxicity to even higher organisms. This work investigated the removal of EtBr from aqueous solutions by a naturally occurring palygorskite (PFl-1) clay mineral via systematic batch adsorption experiments under different physicochemical conditions. EtBr existed in an undissociated form at pH ~7, and was adsorbed on PFl-1 obeying the Freundlich isotherm model. The maximum EtBr adsorption capacity was 285 mmol/kg. The best fitted kinetic model for EtBr adsorption was the pseudo-second order model. The amounts of exchangeable cations desorbed from PFl-1 during EtBr adsorption was linearly correlated to the amounts of EtBr adsorbed, with a slope of 0.97, implying that a cation exchange-based adsorption mechanism was dominating. Additionally, dimerization of EtBr molecules via bromide release assisted an increased EtBr removal by PFl-1 at high adsorbate concentrations. Detailed x-ray diffraction, Fourier transform infrared, scanning electron imaging and energy dispersive x-ray analyses confirmed that EtBr adsorption occurred dominantly on the surface of palygorskite which mineralogically constituted 80% of the bulk PFl-1 adsorbent. A small portion of EtBr was also adsorbed by PFl-1 through intercalation onto the smectite impurity (10%) in PFl-1. This study suggested that PFl-1 could be an excellent natural material for removing EtBr from pharmaceutical and laboratory wastewater.

Refereed/Peer-reviewed Poly- and perfluoroalkyl substances (PFASs) are synthetic chemicals, which are introduced to the environment through anthropogenic activities. Aqueous film forming foam used in firefighting, wastewater effluent, landfill leachate, and biosolids are major sources of PFAS input to soil and groundwater. Remediation of PFAS contaminated solid and aqueous media is challenging, which is attributed to the chemical and thermal stability of PFAS and the complexity of PFAS mixtures. In this review, remediation of PFAS contaminated soils through manipulation of their bioavailability and destruction is presented. While the mobilizing amendments (e.g., surfactants) enhance the mobility and bioavailability of PFAS, the immobilizing amendments (e.g., activated carbon) decrease their bioavailability and mobility. Mobilizing amendments can be applied to facilitate the removal of PFAS though soil washing, phytoremediation, and complete destruction through thermal and chemical redox reactions. Immobilizing amendments are likely to reduce the transfer of PFAS to food chain through plant and biota (e.g., earthworm) uptake, and leaching to potable water sources. Future studies should focus on quantifying the potential leaching of the mobilized PFAS in the absence of removal by plant and biota uptake or soil washing, and regular monitoring of the long-term stability of the immobilized PFAS

Land‐based enhanced rock weathering (ERW) is a biogeochemical carbon dioxide removal (CDR) strategy aiming to accelerate natural geological processes of carbon sequestration through application of crushed silicate rocks, such as basalt, to croplands and forested landscapes. However, the efficacy of the approach when undertaken with basalt, and its potential co‐benefits for agriculture, require experimental and field evaluation. Here we report that amending a UK clay‐loam agricultural soil with a high loading (10 kg/m2) of relatively coarse‐grained crushed basalt significantly increased the yield (21 ± 9.4%, SE ) of the important C4 cereal Sorghum bicolor under controlled environmental conditions, without accumulation of potentially toxic trace elements in the seeds. Yield increases resulted from the basalt treatment after 120 days without P‐ and K‐fertilizer addition. Shoot silicon concentrations also increased significantly (26 ± 5.4%, SE ), with potential benefits for crop resistance to biotic and abiotic stress. Elemental budgets indicate substantial release of base cations important for inorganic carbon removal and their accumulation mainly in the soil exchangeable pools. Geochemical reactive transport modelling, constrained by elemental budgets, indicated CO2 sequestration rates of 2–4 t CO2/ha, 1–5 years after a single application of basaltic rock dust, including via newly formed soil carbonate minerals whose long‐term fate requires assessment through field trials. This represents an approximately fourfold increase in carbon capture compared to control plant–soil systems without basalt. Our results build support for ERW deployment as a CDR technique compatible with spreading basalt powder on acidic loamy soils common across millions of hectares of western European and North American agriculture.

Nanoscale zero-valent iron (NZVI) and NZVI supported onto montmorillonite (NZVI-Mt) were synthetized and used in this study to remove Se

In China, more than 10,000 tons of bean-worm, which is rich in protein (68.5%) and essential amino acids (52.8%), is consumed annually. Thus, a large amount of bean-worm skin waste is generated, and is often indiscriminately disposed of, potentially causing environment problems. In this study, bean-worm skin (BWS) waste was pyrolyzed at 500 °C to produce biochar (BWS-BC), and the surface properties of BWS and BWS-BC were characterized using various spectroscopic techniques. Pb(II) adsorption properties of BWS and the corresponding biochar as a function of solution pH, contact time, and equilibrium concentration of Pb(II) were examined using adsorption isotherm, kinetics and thermodynamics studies. The maximum Pb(II) adsorption capacities based on the Langmuir isotherm model were calculated as 45 and 62 mg g−1 for BWS and BWS-BC, respectively, which were comparable to the values obtained for biochars derived from other agro-wastes. The adsorption feasibility, favorability and spontaneity of Pb(II), as derived from the thermodynamic parameters, indicated that chemisorption and precipitation (e.g., hydroxypyromorphite) were the main adsorption mechanism in case of BWS and BWS-BC, respectively. Thus, conversion of BWS to biochar for Pb(II) adsorption can be considered as a feasible, promising and high value-added approach for BWS recycling. Refereed/Peer-reviewed

The staggering production of rock dusts and quarry by-products of mining activities poses an immense environmental burden that warrants research for value-added recycling of these rock mineral powders (RMP). In this study, an incubation experiment was conducted to determine potassium (K) and micronutrients (Zn, Cu, Fe and Mn) release from a quarry RMP to support plant nutrition. Four different size fractions of the RMP were incubated with organic amendments (cow dung and legume straw) under controlled conditions for 90 days. Samples were collected at different intervals (7, 15, 30, 45, 60 and 90 days) for the analysis of available K and micronutrients in the mineral-OM mixtures and leachates. There was a significant (p

The present study shows the potential of an extracellular polymeric substance (EPS) produced by Bacillus licheniformis strain KX657843 isolated from earthworm (Metaphire posthuma) gut in the sorption of Cu(II) and Zn(II) and in flocculation. After harvesting bacterial cells from sucrose supplemented denitrifying culture medium, the EPS was extracted following ethanolic extraction method. The Fourier Transform Infrared Spectroscopy (FTIR) and 1H and 13C Nuclear Magnetic Resonance (NMR) of EPS revealed its functional groups, electronegative constituents, unsaturated carbon, and carbonyl groups. The negatively charged functional groups of carbohydrates and protein moiety of the EPS endowed it with heavy metal binding capacity through electrostatic interactions. The highest flocculation activity (83%) of EPS was observed at 4 mg L&minus, 1 and pH 11. The metal sorption by EPS increased with increasing pH. At pH 8, the EPS was able to remove 86 and 81% Cu(II) and Zn(II), respectively, from a 25 mg L&minus, 1 metal solution. 94.8% of both the metals at 25 mg L&minus, 1 metal solutions were removed by EPS at EPS concentration of 100 mg L&minus, 1. From Langmuir isotherm model, the maximum sorption capacities of EPS were calculated to be 58.82 mg g&minus, 1 for Cu(II) and 52.45 mg g&minus, 1 for Zn(II). The bacterial EPS showed encouraging flocculating and metal sorption properties. The potential to remove Cu(II) and Zn(II) implies that the EPS obtained from the earthworm gut bacteria can be used as an effective agent for environmental remediation of heavy metals and in bioflocculation.

In recent years, the cultivation of genetically modified (GM) crops has become a topic of great interest, due in part to the considerable public controversy, which exists concerning their potential benefits or adverse effects. Since the development of the first GM crop about 25 years ago, a diverse range of new cultivars have been released into the environment which were developed by employing advanced molecular techniques to introduce new beneficial genes from a wide variety of sources. While GM crops have great potential for enhancing agricultural production, their potential impacts on soil biota are only partially understood and information on their long-term impact on soil biota is scant. Several recent studies have indicated that GM crops may cause changes in both the invertebrate and microorganism soil biota associated with these crops, with some laboratory-based experiments even revealing transfer of genes from GM plants to native soil bacteria. However, processes such as gene transfer and stable inheritance to subsequent generations remain unproven in natural soil systems. In addition, although significant research efforts have recently been directed towards understanding the effects of GM crops on soil biota, the wide variation in the scientific observations has often hindered an accurate understanding of the issues. Thus, this review collated and synthesized all available information on the microbiological and biochemical effects of GM crops on soil biota with a special focus on GM Bt-cotton. The review also addressed the key issues associated with the use of GM crops including herbicide resistance, transgene flow and explored the plausibility of horizontal gene transfer in soil. Refereed/Peer-reviewed

Terrestrial and aquatic pollution by particulate plastics originates from urban and industrial waste sites, sewage outlets, stormwater, litter transported by systems, and litter discarded by the general public. Nanoplastics and microplastics are tiny plastic particles in different forms like foams, fragments, and fibers. Microplastic by-products include dust from cutting and polishing plastic items and by-products from maintenance of painted metal constructions, such as bridges and buildings, and high pressure washing of painted items. Biodegradable and chemically degradable particulate plastic products are frequently offered as better alternatives to traditional plastic items. Components of the infrastructure, such as stormwater drainage systems and garbage cans, are both contributors to the problem of plastic pollution in the marine environment and important source reduction measures. Particulate plastic solid wastes represent a major environmental problem, but innovations in the treatment and sustainable management of these waste resources can provide economic and social benefits.

In this work, the occurrence of contaminants in drinking water sources was described in relation to their treatment options based on both conventional (e.g., coagulation-flocculation, sedimentation filtration, and chlorination) and advanced treatment techniques (e.g., membrane filtration, ozonation, and biofiltration). However, due to apparent drawbacks of these methods (e.g., formation of disinfection by-products (DBPs)), it is desirable to develop an alternative option for safe drinking water. In this respect, biochar is recognized as an effective candidate to resolve the limitations in treating common pollutants typically occurring in drinking water such as microbial contaminants, inorganic contaminants, heavy metals, volatile organic compounds (VOCs), pharmaceuticals and personal care products (PPCPs), and endocrine disrupting chemicals (EDCs). As biochar can exhibit different types of interactions with adsorbates, its sorption processes can be explained by diverse mechanisms, e.g., π-π electron donor-acceptor interactions, complexation, precipitation, H-bonding, and electrostatic attraction. In light of the attractive features of biochar (e.g., enhanced sorption properties, cost-effectiveness, and environmentally friendly nature), we offer in-depth discussion on biochar-based water treatment technologies for large-scale water purification operation.HighlightsOccurrence of various contaminants in drinking water sources are discussed.Human health impacts of exposure to drinking water contaminants are highlighted.Performances and limitations of conventional and advanced water treatment technologies are discussed.Potentials of pristine and modified biochars for drinking water purification are emphasized.Feasibility and importance of biochar-based large-scale water treatment technologies are highlighted. Occurrence of various contaminants in drinking water sources are discussed. Human health impacts of exposure to drinking water contaminants are highlighted. Performances and limitations of conventional and advanced water treatment technologies are discussed. Potentials of pristine and modified biochars for drinking water purification are emphasized. Feasibility and importance of biochar-based large-scale water treatment technologies are highlighted.

Modern agriculture fundamentally relies on an extensive use of agrochemicals to enhance crop productivity by controlling harmful pests, pathogens, and undesirable weeds. However, currently, we have reached a stage where several threats are emerging on food security, human and environmental health, maintenance of ecological balance, and conservation of the soil biodiversity. Long-term unbalanced use of agrochemicals may lead to community shift of beneficial microorganisms with dangerous consequences such as the development of antimicrobial resistance. Agrochemicals usage in farming systems may adversely influence soil microorganisms that are mainly involved in nutrient cycling processes, such as nitrogen fixation, phosphorus solubilization, and other essential nutrient biotransformation. The recent report established that some agrochemicals reduce biochemical reaction and activities of soil enzymes that are key indicators of soil microbiological health. This chapter focuses on the effects of applied agropesticides on soil microbiological and biochemical health attributes under different cropping systems.

Consumption of rice and rice products can be a significant exposure pathway to inorganic arsenic (iAs), which is a group 1 carcinogen to humans. The UK follows the current European Commission regulations so that iAs concentrations must be < 0.20 mg kg−1 in white (polished) rice and 0.1 mg kg−1 were selected for As speciation using HPLC-ICP-MS. Based on the average concentration of iAs of our samples, we calculated values for the Lifetime Cancer Risk (LCR), Target Hazard Quotient (THQ) and Margin of Exposure (MoE). We found a statistically significant difference between organically and non-organically grown rice. We also found that brown rice contained a significantly higher concentration of iAs compared to white or wild rice. Notably, 28 rice samples exceeded the iAs maximum limit stipulated by the EU (0.1 mg kg−1) with an average iAs concentration of 0.13 mg kg−1; therefore consumption of these rice types could be riskier for infants than adults. Based on the MoE, it was found that infants up to 1 year must be restricted to a maximum of 20 g per day for the 28 rice types to avoid carcinogenic risks. We believe that consumers could be better informed whether the marketed product is fit for infants and young children, via appropriate product labelling containing information about iAs concentration. Nearly half of the 55 rice samples marketed in the UK are unfit for infant food purposes, whereas iAs levels pose a minimal health risk to adults Refereed/Peer-reviewed

Halloysite nanoclay was utilized to retain aqueous oxytetracycline (OTC) which is extensively used in the veterinary industry. The micro-structure and functionality of the nanoclay were characterized through spectroscopic techniques before and after adsorption. The OTC removal experiments were performed at different pH conditions (pH 3.0-9.0), ionic strengths (0.001, 0.01, 0.1 M NaNO3) and contact time (up to 32 h) at an initial 25 mg/L OTC concentration with 1.0 g/L halloysite. Oxytetracycline adsorption was pH dependent, and the best pH was observed in the range of pH 3.5-5.5 at a 0.001 M ionic strength. At pH 3.5, the maximum OTC adsorption amount was 21 mg/g which translated to 68% removal of the initial OTC loading. Positively charged inner lumen and negatively charged outer lumen of the tubular halloysite structure led to form inner-sphere complexes with the anionic and cationic forms of OTC, respectively. A rapid adsorption of OTC was observed in the kinetic study where 62% OTC was adsorbed in 90 min.. Pseudo-second order equation obeyed by the kinetic data indicated that the adsorption was governed by chemisorption, whereas Hill isotherm equation was the most fitted with a maximum adsorption capacity of 52.4 mg/g indicating a cooperative adsorption phenomenon. usc Refereed/Peer-reviewed

Capsule: Sulfide-modified α-FeOOH remediates both low and high arsenic/antimony levels under varying pH and competitive anions – conditions common in wastewater. © 2020 Elsevier LtdEfficient elimination of As(V) and Sb(V) from wastewater streams has long been a major challenge. Herein, sulfide-modified α-FeOOH adsorbent was fabricated via a simple sulfidation reaction for removing As(V) and Sb(V) from aqueous media. Compared with the pristine α-FeOOH, sulfide-modified α-FeOOH increased the adsorption of As(V) from 153.8 to 384.6 mg/g, and Sb(V) adsorption from 277.8 to 1111.1 mg/g. The enhanced adsorption of both As(V) and Sb(V) was maintained at the pH range from 2 to 11, and was not interfered by various coexisting anions such as Cl−, SO42−, NO3−, SiO32− and PO43−. The adsorption affinity increased from 0.0047 to 0.0915 and 0.0053 to 0.4091 for As(V) and Sb(V), respectively. X-ray photoelectron spectroscopic investigation demonstrated a reductive conversion of As(V) to As(III) during the adsorption process with sulfide-modified α-FeOOH, but with no obvious variation of Sb(V) speciation. While the removal mechanism for As(V) was reduction followed by adsorption via hydroxyl groups, mainly surface complexation was involved in the removal of Sb(V). This study presented a simple strategy to enhance the adsorption capacity and adsorption affinity of α-FeOOH toward As(V)/Sb(V) via sulfide-modification. Refereed/Peer-reviewed

This chapter provides an overview of particulate plastics as a source and sink for heavy metal(loid)s in the environment. Particulate plastics in the terrestrial and aquatic environments are a group of synthetic polymer fragments or beads ranging in diameter from roughly 5 mm down to the nano-meter scale. The accumulated particulate plastics in soil can be transported to the aquatic environment through soil erosion, which is one of the main processes that allows the transport of particulate plastics from the terrestrial to the aquatic ecosystem. Heavy metal(loid)s are elements that have properties in between metals and non-metals. Particulate plastics impact the dynamics of metal(loid)s in terrestrial and aquatic environments through both acting as a source and sink for metal(loid)s. In environmental toxicology, the “source” can be defined where pollution is emitted to the environment, or where the pollution originates. Particulate plastics act as a “source” when they release a pollutant into the environment.

Modern agricultural practices use a huge amount of agro-pesticides to control insect pests, pathogens, and unwanted weeds. Many of such agrochemicals persist in the soil and plant systems for long time and pose a risk of migration into the drinking water sources and food chain. Often these agrochemicals occur as a mixture of multiple compounds in the soil due to their simultaneous and/or subsequent seasonal applications. The mobility, fate, and transformation of agrochemicals depend largely on soil types, especially the type and content of soil clays, organic matter content, pH, and microbial activity. The sorption–desorption behaviors of agrochemicals on soil clays, which are the most reactive particle components of soils, may alter significantly when these compounds appear as a mixture. This chapter aims to discuss various soil attributes that control the sorption–desorption of agrochemical contaminants in soils under different soil–plant systems.

Lead (Pb(II)) pollution in water poses a serious threat to human health in many parts of the world. In the past decades, research has been aimed at developing efficient and cost-effective methods to address the problem. In this study, dimethyl sulfoxide (DMSO) and potassium acetate (K-Ac) intercalated kaolinite complexes were synthesized and subsequently utilized for Pb(II) removal from water. The intercalation of kaolinite with DMSO was found to be useful for expanding the interlayer space of the clay mineral from 0.72 to 1.12 nm. Kaolinite intercalation with K-Ac (KDK) increased the interlayer space from 1.12 to 1.43 nm. The surface area of KDK was found to be more than threefold higher as compared to natural kaolinite (NK). Batch experimental results revealed that the maximum Pb(II) uptake capacity of KDK was 46.45 mg g−1 which was higher than the capacity of NK (15.52 mg g−1). Reusability studies showed that KDK could be reused for 5 cycles without substantially losing its adsorption capacity. Furthermore, fixed-bed column tests confirmed the suitability of KDK in continuous mode for Pb(II) removal. Successful application of intercalated kaolinite for Pb(II) adsorption in batch and column modes suggests its application in water treatment (especially removal of divalent metals). Electronic supplementary material The online version of this article (10.1007/s11356-019-06845-w) contains supplementary material, which is available to authorized users.

Efficient decontamination of Sb(V) from water has long been an urgent task owing to its grave threat to human health. Herein, Y-based MOFs (MOF-Y and NH2-MOF-Y) were synthesized for effective adsorption of Sb(V) from aqueous solution, and the stability of the Y based MOFs were estimated. Kinetic and isotherms results indicated that the pseudo-second order kinetic (R2 > 0.90) and Langmuir isotherm models (R2 > 0.97) quite well described the adsorption of Sb(V) on Y-based MOFs, revealed that the uptake of Sb(V) on Y-based MOFs were followed by a monolayer chemical adsorption process. The maximum adsorption capacities of Sb(V) calculated from the Langmuir model were 161.3 and 151.5 mg/g for MOF-Y and NH2-MOF-Y, respectively. The Y-based MOFs exhibited strong water and chemical stability, it could be utilized for removal Sb(V) under wide pH range and various concentration of Sb(V). The spent adsorbents could be successfully regenerated by NaCl (5 mol/L) solution for further utilization without damaging the crystal structure of Y-based MOFs. X-ray photoelectron spectroscopy (XPS) and energy dispersive spectroscopy (EDS) results revealed that the formation of inner-sphere Y-O-Sb complex between Y-oxo-clusters and Sb(V) was the dominant adsorption mechanism, while the co-precipitation of Y^(+3) and Sb(V) was also partially contributed the Sb(V) adsorption. High stability together with high Sb(V) adsorption capacity and excellent recyclability endow the Y-based MOFs as promising adsorbents for Sb(V) removal from wastewater. Refereed/Peer-reviewed

The effect of humic substances (HS) and their different fractions (humic acids (HA) and hymatomelanic acids(HMA)) on the toxicity of zinc and lead to different strains of bacteria was studied. All tested bacteria demonstrated a lower resistance to zinc than lead showing minimum inhibitory concentrations of 0.1 − 0.3 mM and 0.3–0.5 mM, respectively. The highest resistance to lead was characteristic of Pseudomonas chlororaphisPCL1391 and Rhodococcus RS67, while Pseudomonas chlororaphis PCL1391 showed the greatest resistance to zinc. The combined fractions of HS and HA alone reduced zinc toxicity at all added concentrations of the organic substances (50 – 200 mg L⁻¹) to all microorganisms, while hymatomelanic acids reduced zinc toxicity to Pseudomonas chlororaphis PCL1391 at 200 mg L⁻¹ organic concentration only. The HS fractions imparted similar effects on lead toxicity also. This study demonstrated that heavy metal toxicity to bacteria could be reduced through complexation with HS and their fractions. This was particularly true when the metal-organic complexes held a high stability, and low solubility and bioavailability. Refereed/Peer-reviewed

Nickel (Ni) is a potentially toxic element that contaminates soil and water, threatens food and water security, and hinders sustainable development globally. Biochar has emerged as a promising novel material for remediating Ni-contaminated environments. However, the potential for pristine and functionalized biochars to immobilize/ adsorb Ni in soil and water, and the mechanisms involved have not been systematically reviewed. Here, we critically review the different dimensions of Ni contamination and remediation in soil and water, including its occurrence and biogeochemical behavior under different environmental conditions and ecotoxicological hazards, and its remediation using biochar. Biochar is effective in immobilizing Ni in soil and water via ion exchange, electrostatic attraction, surface complexation, (co)precipitation, physical adsorption, and reduction due to the biogeochemistry of Ni and the interaction of Ni with surface functional groups and organic/inorganic compounds contained in biochar. The efficiency for Ni removal is consistently greater with functionalized than pristine biochars. Physical (e.g., ball milling) and chemical (e.g., alkali/acidic treatment) activation achieve higher surface area, porosity, and active surface groups on biochar that enhance Ni immobilization. This review highlights possible risks and challenges of biochar application in Ni remediation, suggests future research directions, and discusses implications for environmental agencies and decision-makers. usc Refereed/Peer-reviewed

Aqueous film-forming foam, used in firefighting, and biowastes, including biosolids, animal and poultry manures, and composts, provide a major source of poly- and perfluoroalkyl substances (PFAS) input to soil. Large amounts of biowastes are added to soil as a source of nutrients and carbon. They also are added as soil amendments to improve soil health and crop productivity. Plant uptake of PFAS through soil application of biowastes is a pathway for animal and human exposure to PFAS. The complexity of PFAS mixtures, and their chemical and thermal stability, make remediation of PFAS in both solid and aqueous matrices challenging. Remediation of PFAS in biowastes, as well as soils treated with these biowastes, can be achieved through preventing and decreasing the concentration of PFAS in biowaste sources (i.e., prevention through source control), mobilization of PFAS in contaminated soil and subsequent removal through leaching (i.e., soil washing) and plant uptake (i.e., phytoremediation), sorption of PFAS, thereby decreasing their mobility and bioavailability (i. e., immobilization), and complete removal through thermal and chemical oxidation (i.e., destruction). In this review, the distribution, bioavailability, and remediation of PFAS in soil receiving solid biowastes, which include biosolids, composts, and manure, are presented. usc Refereed/Peer-reviewed

Mafic igneous rocks, such as basalt, are composed of abundant calcium- and magnesium-rich silicate minerals widely proposed to be suitable for scalable carbon dioxide removal (CDR) by enhanced rock weathering (ERW). Here, we report a detailed characterization of the mineralogy, chemistry, particle size and surface area of six mined basalts being used in large-scale ERW field trials. We use 1-D reactive transport modelling (RTM) of soil profile processes to simulate inorganic CDR potential via cation flux (Mg2+, Ca2+, K+ and Na+) and assess the release of the essential plant nutrients phosphorus (P) and potassium (K) for a typical clay-loam agricultural soil. The basalts are primarily composed of pyroxene and plagioclase feldspar (up to 71 wt%), with accessory olivine, quartz, glass and alkali feldspar. Mean crushed particle size varies by a factor of 10, owing to differences in the mining operations and grinding processes. RTM simulations, based on measured mineral composition and N-2-gas BET specific surface area (SSA), yielded potential CDR values of between c. 1.3 and 8.5 t CO2 ha(-1) after 15 years following a baseline application of 50 t ha(-1) basalt. The RTM results are comparative for the range of inputs that are described and should be considered illustrative for an agricultural soil. Nevertheless, they indicate that increasing the surface area for slow-weathering basalts through energy intensive grinding prior to field application in an ERW context may not be warranted in terms of additional CDR gains. We developed a function to convert CDR based on widely available and easily measured rock chemistry measures to more realistic determinations based on mineralogy. When applied to a chemistry dataset for >1300 basalt analyses from 25 large igneous provinces, we simulated cumulative CDR potentials of up to c. 8.5 t CO2 ha(-1) after 30 years of weathering, assuming a single application of basalt with a SSA of 1 m(2) g(-1). Our RTM simulations suggest that ERW with basalt releases sufficient phosphorus (P) to substitute for typical arable crop P-fertiliser usage in Europe and the USA offering potential to reduce demand for expensive rock-derived P. Refereed/Peer-reviewed

Hierarchical porous carbon (HPC) has attracted increasing research interest for energy and environmental applications. HPC is conventionally fabricated by activated carbon, which potentially causes hidden environmental burdens. To overcome this issue, biochar, a promising renewable precursor, offers an attractive raw material substitute and has already been explored for the preparation of low-cost HPC. Recent studies have demonstrated that HPC exhibited great applications in capacitive energy storage, owning to its easily tuned physicochemical and electrochemical properties. Besides, biochar-based HPC with a three-dimensional (3D) interconnected controllable pore structure, high specific surface area (SSA), and pore volume (PV) can provide smaller resistance and shorter diffusion pathways for the transport of ions. Importantly, most recent research efforts have been made on the synthesis of biochar-based engineered hierarchical porous carbons (EHPCs) from biomass/biochar or developed from the HPC. A templating technique, heteroatom, and metal oxides doping have been applied to develop the biochar-based EHPC to improve 3D pore structure or/and expose abundant active sites and subsequently enhance the capacitive charge storage performance. In this review, recent advances in the applications of biochar-based HPC or EHPC for capacitive charge storage, e.g., capacitive deionization (CDI) and a supercapacitor (SC) are summarized and discussed. This review concludes with several perspectives to provide possible future research directions for the preparation and applications of biochar-based EHPC for capacitive charge storage. usc Refereed/Peer-reviewed

The use of modified clay minerals for adsorbing arsenic (As) in contaminated soils is an underexplored area of research. The adsorption behavior of As onto inorganically modified smectite and kaolinite both in aqueous and soil media was studied. X-ray diffraction, infra-red spectroscopy, scanning and transmission electron microscopy studies confirmed successful modification of smectite through Fe-exchange and Ti-pillaring, and kaolinite through phosphate binding. The modified smectites were more efficient than phosphate-bound kaolinite in adsorbing As both in water and soil systems. Kinetic study revealed that the clay products reached adsorption equilibrium within 3 h, and the data well fitted to the power function and simple Elovich equation (R 2 > 0.90). The Freundlich isotherm model best described the As adsorption data (R 2 > 0.86) of the modified clay products in both the systems. The Ti-pillared smectite exhibited the highest As adsorption capacity (156.54 μg g − 1 ) in the aqueous medium, while the Fe-exchanged smectite was the best material in the soil system (115.63 μg g − 1 ). The partition coefficient (K d ) and adsorption efficiency (%) data also maintained the similar trend. Precipitation of As and binuclear complex formation also took place in the soil system which made the metalloid non-labile as the time passed. The inorganically modified clay products reported here hold a great potential to adsorb As in contaminated groundwater, drinking water as well as soil. Refereed/Peer-reviewed

One of the key challenges in water treatment industry is the removal of organic compounds by cost-effective methods. This study evaluated the adsorptive removal of dissolved organic carbon (DOC) from reservoir water using fuller’s earth (FE) in comparison with natural (SQ) and modified quartz (MSQ) sands. The removal capacities of FE at different contact times, pH levels, adsorbent dosages and initial DOC concentrations were compared with both the quartz sands. The optimum DOC removals by FE and SQs were achieved at contact time of 60 and 30 min, pH level of 6 and 4, and at adsorbent dose of 1.5 g/150 mL and 10 g/100 mL, respectively. The adsorption capacity of FE (1.05 mg/g) was much higher compared to the MSQ (0.04 mg/g) and SQ (0.01 mg/g). Adsorption equilibrium data better fitted to the Freundlich model than to the Langmuir model, suggesting that adsorption occurred primarily through multilayer formation onto the surfaces of FE and SQ. The pseudo-second-order model described the uptake kinetics more effectively than the pseudo-first-order and intra-particle diffusion models, indicating that the mechanism was primarily governed by chemisorption. These observations were well supported by the physiochemical characteristics and charge behaviour of the adsorbents. In mass-transfer study, the results of liquid film diffusion model showed that the adsorption of DOC on FE was not controlled by film diffusion, but other mechanisms also played an essential role. This study demonstrates that FE is an effective adsorbent for the removal of DOC in surface water treatment. Refereed/Peer-reviewed

Rapid surge of interest for carbon nanotube (CNT) in the last decade has made it an imperative member of nanomaterial family. Because of the distinctive physicochemical properties, CNTs are widely used in a number of scientific applications including plant sciences. This review mainly describes the role of CNT in plant sciences. Contradictory effects of CNT on plants physiology are reported. CNT can act as plant growth inducer causing enhanced plant dry biomass and root/shoot lengths. At the same time, CNT can cause negative effects on plants by forming reactive oxygen species in plant tissues, consequently leading to cell death. Enhanced seed germination with CNT is related to the water uptake process. CNT can be positioned as micro-tubes inside the plant body to enhance the water uptake efficiency. Due to its ability to act as a slow-release fertilizer and plant growth promoter, CNT is transpiring as a novel nano-carbon fertilizer in the field of agricultural sciences. On the other hand, accumulation of CNT in soil can cause deleterious effects on soil microbial diversity, composition and population. It can further modify the balance between plant-toxic metals in soil, thereby enhancing the translocation of heavy metal(loids) into the plant system. The research gaps that need careful attention have been identified in this review. Refereed/Peer-reviewed

Clay-bacterial interaction can significantly influence the biodegradation of organic contaminants in the environment. A moderate heat treatment of palygorskite could alter the physicochemical properties of the clay mineral and thus support the growth and function of polycyclic aromatic hydrocarbon (PAH)-degrading bacteria. By using 14C-labelled phenanthrene and a model bacterium Burkholderia sartisoli, we studied the mineralization of phenanthrene on the surface of a moderately heat-treated (up to 400 °C) palygorskite. The heat treatment at 400 °C induced a reduction of binding sites (e.g., by the elimination of organic matter and/or channel shrinkage) in the palygorskite and thus imparted a weaker sequestration of phenanthrene on its surface and within the pores. As a result, a supplement with the thermally modified palygorskite (400 °C) significantly increased (20–30%; p < 0.05) the biomineralization of total phenanthrene in a simulated soil slurry system. These results are highly promising to develop a clay mineral based technology for the bioremediation of PAH contaminants in water and soil environments. Refereed/Peer-reviewed

Clays including bentonite hold a great potential in improving the efficacy of organic contaminants degradation by bacteria. However, the mechanisms of interactions involving both biotic (microorganisms) and abiotic (clays) components during bioremediation are largely unknown. Here, we report the interaction of a biosurfactant producing bacterium, Pseudoxanthomonas kaohsiungensis, with bentonite clay. Using instrumental analyses including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, inductively coupled plasma mass spectroscopy (ICP-MS), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) techniques we investigate the microstructural changes of smectite following introduction of the bacterium. The interaction resulted in a spherical clay-bacterial micro-agglomerate formation which deciphered an enhanced growth of the bacterium in a minimal medium supplemented with traces of olive oil. The bacterium brought about a significant dissolution of silicon (Si) preferentially from the tetrahedral silica edges of smectites. The deposition of bacterial biosurfactants and exopolysaccharides (EPS) slightly expanded the smectite interlayers and modified the clay's interaction with water molecules. This study has direct implication in the clay-mediated bioremediation of hydrophobic organic contaminants in the environment. Refereed/Peer-reviewed

Chromium (Cr) is one of the common metals present in the soils and may have an extremely deleterious environmental impact depending on its redox state. Among two common forms, trivalent Cr(III) is less toxic than hexavalent Cr(VI) in soils. Carbon (C) based materials including biochar could be used to alleviate Cr toxicity through converting Cr(VI) to Cr(III). Incubation experiments were conducted to examine Cr(VI) reduction in different soils (Soil 1: pH 7.5 and Soil 2: pH 5.5) with three manures from poultry (PM), cow (CM) and sheep (SM), three respective manure-derived biochars (PM biochar (PM-BC), CM biochar (CM-BC) and SM biochar (SM-BC)) and two modified biochars (modified PM-BC (PM-BC-M) and modified SM-BC (SM-BC-M)). Modified biochar was synthesized by incorporating chitosan and zerovalent iron (ZVI) during pyrolysis. Among biochars, highest Cr(VI) reduction was observed with PM-BC application (5%; w/w) (up to 88.12 mg kg−1; 45% reduction) in Soil 2 (pH 5.5). The modified biochars enhanced Cr(VI) reduction by 55% (SM-BC-M) compared to manure (29%, SM) and manure-derived biochars (40% reduction, SM-BC). Among the modified biochars, SM-BC-M showed a higher Cr(VI) reduction rate (55%) than PM-BC-M (48%) in Soil 2. Various oxygen-containing surface functional groups such as phenolic, carboxyl, carbonyl, etc. on biochar surface might act as a proton donor for Cr(VI) reduction and subsequent Cr(III) adsorption. This study underpins the immense potential of modified biochar in remediation of Cr(VI) contaminated soils. Refereed/Peer-reviewed

Low-temperature oxidative degradation of formaldehyde (HCHO) using non-noble metal catalysts is challenging. Herein, novel manganese dioxide (MnO

Humic substances with or without chemical modification can serve as environmentally benign and inexpensive adsorbents of potentially toxic trace elements (PTTEs) in the environment. The present study investigated the absorption of Pb, Zn, Cu and Ni by natural and potassium persulfate (K

Land-based enhanced rock weathering (ERW) is a biogeochemical carbon dioxide removal (CDR) strategy aiming to accelerate natural geological processes of carbon sequestration through application of crushed silicate rocks, such as basalt, to croplands and forested landscapes. However, the efficacy of the approach when undertaken with basalt, and its potential co-benefits for agriculture, require experimental and field evaluation. Here we report that amending a UK clay-loam agricultural soil with a high loading (10 kg/m

Ammonia (NH3) volatilization is considered as one of the major mechanisms responsible for the loss of nitrogen (N) from soil-plant systems worldwide. This study investigated the effect of biochar amendment to a calcareous soil (pH 7.8) on NH3 volatilization and plant N uptake. In particular, the effect of biochar's feedstock and application rate on both NH3 volatilization and plant growth were quantified using a specially designed closed chamber system. Two well-characterized biochars prepared from poultry manure (PM-BC) and green waste compost (GW-BC) were applied to the soil (0, 0.5, 1, 1.5 and 2% w/w equivalent to 0, 7.5, 15, 22 and 30 t ha−1) and wheat (Triticum aestivum, variety: Calingiri) was grown for 30 days. Both PM-BC and GW-BC decreased NH3 volatilization to a similar degree (by 47 and 38%, respectively), in the soil-plant system compared to the unamended control. Higher plant biomass production of up to 70% was obtained in the closed chamber systems with the addition of biochar. The increase in plant biomass was due to the reduction in N loss as NH3 gas, thereby increasing the N supply to the plants. Plant N uptake was improved by as much as 58% with biochar addition when additional NPK nutrients were supplied to the soil. This study demonstrates that the application of biochars can mitigate NH3 emission from calcareous agricultural cropping soil and that the retained N is plant-available and can improve wheat biomass yield Refereed/Peer-reviewed

Green synthesis of nanoparticles is becoming increasingly popular as a simple and environmentally friendly method. In this study, iron-based nanoparticles (Fe-NPs) were successfully prepared using a peanut skin extract, where the peanut skin as an agricultural waste product was easy to obtain in large quantities, relatively inexpensive and also environmentally friendly. The average particle size of the produced Fe-NPs changed with their post-synthesis drying conditions. Under vacuum drying at 60 ⁰C, the smallest average particle size obtained was 10.6 nm. The synthesized Fe-NPs had a core shell-like structure, inwhich the core was composed of Fe⁰, and the shell was a layered coating composed of biomolecules(e.g. anthocyanins, flavonols, phenolic compounds, epicatechin), iron oxides, Fe coordination compounds and iron-carbon alloys. Thereafter Fe-NPs (2 g L⁻¹) prepared under different drying conditions were evaluated for their ability to remove Cr(VI) from aqueous solutions at pH of 4.7 and 25 ⁰C. Fe-NPs obtained under vacuum drying at 60 ⁰C performed the best, removing 100% of Cr(VI), from a 10 mg L⁻¹ aqueous solution of Cr(VI) in just one min. Desorption and reuse experiments show that the desorption rate of Cr using 16 M hydrochloric acid and the recycling rate reached 70.2 and 59.9%, respectively. A potential mechanism for Fe NP synthesis involving the formation of intermediate complexes, an electron transfer reaction and adsorption of non-reducing organic macromolecules at the solid-liquid interfaces was proposed. Refereed/Peer-reviewed

Refereed/Peer-reviewed This work aimed at elucidating the role of bacteria present in the gut of the earthworm Metaphire posthuma in plant growth promotion and toxic trace elements (TTEs) bioremediation. We isolated and identified three bacterial strains Bacillus safensis (MF 589718), Bacillus flexus (MF 589717) and Staphylococcus haemolyticus (MF 589719) among which the Bacillus strains appeared to be significantly more potent than the Staphylococcus strain (P

Refereed/Peer-reviewed As one of the important contaminants in wastewater, Pb(II) becomes a severe public health problem because of its non-biodegradable and persistent nature. In this study, reduced graphene oxide (RGO) prepared using green tea extract was successfully used to remove Pb(II) from aqueous solutions. A 96.6% of Pb(Il) was removed at 10 mg/L Pb(II) and 0.4 g/L RGO with pH 4.5 at 30 degrees C, and the adsorption of Pb(II) by RGO followed pseudo-second-order kinetics. To confirm the removal mechanism, various methods (Transmission Electron Microscopy, Raman spectroscopy and X-ray diffraction) were used to characterize RGO before and after Pb(II) adsorption. The results showed that the surface of RGO after Pb(II) adsorption became rougher, and the interlayer spacing increased from 0.36 nm to 0.40 nm, indicating that Pb(II) was adsorbed on the surface and between the layers of RGO. Finally, the adsorption mechanism of Pb(II) by RGO was proposed, Pb(Il) was adsorbed on the surface of RGO via the electrons on the it-bond on RGO and the interaction of Pb(II) with oxygen-containing functional groups, which were supported by the Fourier Transform Infrared and X-ray photoelectron spectroscopy results. (C) 2019 Elsevier Inc. All rights reserved.

Contaminant removal from water involves various technologies among which adsorption is considered to be simple, effective, economical, and sustainable. In recent years, nanocomposites prepared by combining clay minerals and polymers have emerged as a novel technology for cleaning contaminated water. Here, we provide an overview of various types of clay-polymer nanocomposites focusing on their synthesis processes, characteristics, and possible applications in water treatment. By evaluating various mechanisms and factors involved in the decontamination processes, we demonstrate that the nanocomposites can overcome the limitations of individual polymer and clay components such as poor specificity, pH dependence, particle size sensitivity, and low water wettability. We also discuss different regeneration and wastewater treatment options (e.g., membrane, coagulant, and barrier/columns) using clay-polymer nanocomposites. Finally, we provide an economic analysis of the use of these adsorbents and suggest future research directions. usc Refereed/Peer-reviewed

A large number of pharmaceutical drugs, especially the antibiotics, have been used to treat diseases in humans, animals, and plants for a long time. The metabolic degradation rate of these drugs in humans and animals is very low, they could be released into the environment directly through feces or urine in the form of prototype or secondary metabolites, and they can be enriched in the environment, resulting in resistance of a variety of bacteria to antibiotics. This consequently brings a variety of health risks to human beings directly or indirectly. The most important behavior of antibiotics in the environment is adsorption, which not only affects the residence time, distribution, migration, and transformation of these compounds in the environment, but also affects their biological activities in the environment. Clay minerals show remarkable adsorption capacities and ion exchange performances for cationic drugs due to their unique layered structure and high cation exchange ability, and further have broad application prospects in wastewater treatment. Based on the structures and properties of clay minerals, such as rectorite, montmorillonite, palygorskite, illite, kaolinite, bentonite, and other clays, this chapter reviews the research on pharmaceutical drugs especially for the antibiotics’ adsorption on clay minerals or soils with clay components in them.

Toxic trace element (TTE) contamination in urban soils may pose potential health risks, especially in cities with previous industrial activities. This study aimed to investigate soil contamination in urban allotments in Sheffield, the uptake of TTEs in autumn and spring sown onions (Allium cepa), and their potential risks on human health via consumption of the crops. Paired soil and plant samples were taken in triplicates from four private allotments to assess potentially elevated levels of lead (Pb), zinc (Zn), copper (Cu), arsenic (As), and chromium (Cr). These elements in soils exceeded the ambient background levels for England. Both Pb and As exceeded some UK and EU soil tolerable limits. Concentration factors (CF) were calculated as the ratio of trace element in the plant as compared to that in the soil, and uptake rates were in the order Zn>Cu>Cr>Pb>As. Concentrations were higher for most TTEs in spring sown onions (SSO), and had significantly higher CF (p < 0.05) for Pb and Cr than autumn sown onions (ASO), whereas the opposite was true for As. Toxic elements in plants did not exceed FAO/WHO intake limits when considering TTE content per plant and consumption rates. Human health risk assessment calculations using target hazard quotients (THQ) and hazard indexes (HI) indicated that consuming onions alone did not pose an immediate health risk. Refereed/Peer-reviewed

Problems caused by residual organics in treated water include the formation of disinfection by-products (DBP) following reaction with chlorine and being a substrate for microbial regrowth in the drinking water distribution system. Dissolved organic matter (DOM) can only be partially removed by conventional treatment process i.e. coagulation by Al- and Fe-based salts. In the present study, the performance of titanium trichloride (TiCl3) as a coagulant for surface water treatment was studied and compared with conventionally used aluminum sulfate (alum). Jar test experiments were performed at various coagulant doses and pH levels to determine the optimum conditions based on removal efficiencies of dissolved organic carbon (DOC). The zeta potential values were analysed for assessing the destabilisation mechanism of DOM flocs. The TiCl3 showed a significantly higher capacity for DOC removal at pH around 3 at which charge neutralization was found to be the dominant mechanism for the floc formation. This was further evident from the relatively larger floc sizes obtained with TiCl3 treatment. However, destabilization of Ti-flocs occurred at pH 4.5 through an adsorption-enmeshment mechanism due to a highly negative zeta potential. Additionally, fluorescence spectroscopic analyses showed that TiCl3 was more efficient than alum in removing humic compounds. A two-stage treatment process by alum and TiCl3, either as the same chemical or both showed better performance than a single dose treatment. The results indicate that TiCl3 could be an effective alternative coagulant for the treatment of waters, particularly those of low alkalinity and high DOC concentration and low pH wastewaters for removal of hydrophobic compounds and particulate matter. Refereed/Peer-reviewed