Removal of cadmium from aqueous system by shelled Moringa oleifera Lam. seed powder

A critical review on the separation of heavy metal(loid)s from the contaminated water using various agricultural wastes

Wastewater contamination with heavy metal(loids)s has become a worldwide environmental and public health problem due to their toxic and non-degradable nature. Different methods and technologies have been applied for water/wastewater treatment to mitigate heavy metal(loid)-induced toxicity threat to humans. Among various treatment methods, adsorption is considered the most attractive method because of its high ability and efficiency to remove contaminants from wastewater. Agricultural waste-based adsorbents have gained great attention because of high efficiency to heavy metal(loids)s removal from contaminated water. Chemically modified biosorbents can significantly enhance the stability and adsorption ability of the sorbents. The two mathematical models of sorption, Freundlich and Langmuir isotherm models, have mostly been studied. In kinetic modeling, pseudo-second-order model proved better in most of the studies compared to pseudo-first-order model. The ion exchange and electrostatic attraction are the main mechanisms for adsorption of heavy metal(loid)s on biosorbents. The regeneration has allowed various biosorbents to be recycled and reused up to 4-5 time. Most effective eluents used for regeneration are dilute acids. For practical perspective, biosorbent removal efficiency has been elucidated using various types of wastewater and economic analysis studies. Economic analysis of adsorption process using agricultural waste-based biosorbents proved this approach cheaper compared to traditional commercial adsorbents, such as chemically activated carbon. The review also highlights key research gaps to advance the scope and application of waste peels for the remediation of heavy metal(loid)s-contaminated wastewater.

Halophytes for the sustainable remediation of heavy metal-contaminated sites: Recent developments and future perspectives

Increasing land degradation by high level of metal wastes is of prime concern for the global research communities. In this respect, halophytes having specific features like salt glands, exclusion of excess ions, heavy metals (HMs) compartmentalization, large pool of antioxidants, and associations with metal-tolerant microbes are of great promise in the sustainable clean-up of contaminated sites. However, sustainable clean-up of HMs by a particular halophyte plant species is governed considerably by physico-chemical characteristics of soil and associated microbial communities. The present review has shed light on the superiority of halophytes over non-halophytes, mechanisms of metal-remediation, recent developments and future perspectives pertaining to the utilization of halophytes in management of HM-contaminated sites with the aid of bibliometric analysis. The results revealed that the research field is receiving considerable attention in the last 5-10 years by publishing ∼50-90% documents with an annual growth rate of 15.41% and citations per document of 29.72. Asian (viz., China, India, and Pakistan) and European (viz., Spain, Portugal, Belgium, Argentina) countries have been emerged as the major regions conducting and publishing extensive research on this topic. The investigations conducted both under in vitro and field conditions have reflected the inherent potential of halophyte as sustainable research tool for successfully restoring the HM-contaminated sites. The findings revealed that the microbial association with halophytes under different challenging conditions is a win-win approach for metal remediation. Therefore, exploration of new halophyte species and associated microorganisms (endophytic and rhizospheric) from different geographical locations, and identification of genes conferring tolerance and phytoremediation of metal contaminants would further advance the intervention of halophytes for sustainable ecological restoration.

Highly adsorptive protein inorganic nanohybrid of Moringa seeds protein and rice husk nanosilica for effective adsorption of pharmaceutical contaminants

The present study aims to investigate adsorption characteristics and mechanisms of Moringa (MO) seeds protein on nanosilica rice husk and their applications in removal of pharmaceutical residues including the fluoroquinolone antibiotic levofloxacin (LFX) and the nonsteroidal anti-inflammatory drug diclofenac (DCF) in aquatic environment. Molecular weight of MO protein was determined by gel-permeation chromatography (GPC) method while its amino acids were quantified by high performance liquid chromatography (HPLC). The number-(M_n) and weight-average molecular weights (M_w) of MO protein were 1.53 × 10⁴ and 1.61 × 10⁴ g/mol, respectively. Different effective conditions on adsorption protein on nanosilica including contact time, pH, adsorbent dosage, and ionic strength were systematically optimized and found to be 180 min, 10, 10 mg/mL and 1 mM KCl, respectively. The surface charge change by zeta potential, surface modification by Fourier-transform infrared spectroscopy (FT-IR) and adsorption isotherms demonstrated that protein adsorption on nanosilica was governed by both electrostatic and non-electrostatic interactions. Application of protein functionalized nanosilica (ProFNS) in LFX and DCF removal were also thoroughly studied. The selected conditions for LFX and DCF removal using ProFNS were 1 mM KCl for both LFX and DCF; pH 8 and pH 6; contact time 90 and 120 min, and adsorption dosage 10 and 5 mg/ml for LFX and DCF, respectively. Adsorption isotherms of protein on nanosilica as well as LFX and DCF onto ProFNS at different ionic strengths were reasonably fitted by the two-step model while a pseudo-second-order model could fit adsorption kinetic well. The removal of LFX and DCF using ProFNS significantly increased from 51.51% to 87.35%, and 7.97%-50.02%, respectively. High adsorption capacities of 75.75 mg/g for LFX and 59.52 mg/g for DCF, indicate that ProFNS is a great performance for pharmaceutical residues removal in water environment.

Plant biomass as potential economic commodities for agricultural purposes

The world’s population is growing continually and is projected to reach nine billion by the year 2050. This growth rate requires increased and economically viable food production and an adequate supply of quality water to sustain life. Increased food production and supply of water require adding fertilizers and possible recycling of wastewater, to address the improvement of soils’ nutritional status and potable water shortages, respectively. The objectives of this work were to determine the nutrients in sewage-impacted wastewater, borehole water, agricultural waste, and commercial fertilizer (control) materials, and their heavy metal content was also carried out to determine their suitability for use. In addition, Moringa seed pods and Morula nutshells were investigated as a bioremedial approach for the removal of toxic metals from aqueous samples. An attempt to regenerate sorbent was made since the saturated sorbents that contain the metal ions are not safe for disposal as they can pollute the environment. Nutrients were analyzed by HPLC, while metals were analyzed using a Varian 220FS Atomic Absorption Spectrometer operated with air/acetylene. Nonedible agricultural materials were found to contain appreciable amounts of plant nutrients such as nitrates (NO₃^-), nitrites (NO₂^-), and phosphates (PO₄^3-) as well as metal ions such as magnesium, copper, and zinc, which are beneficial for plant growth. Results obtained from analysis of sewage water effluent showed that heavy metal and nutrient concentrations decreased in the treatment stage. The utilization of Moringa oleifera seed pods for metal removal from wastewater is viable and would reduce costs for waste disposal and can offer alternatives to conventional methods for the removal of unwanted or toxic species from the environment. It showed potential for removing selected metal ions such as Pb, Cd, Cu, Fe, and Zn from polluted water. This organically treated wastewater is environmentally friendly and may be used for applications which do not require potable water, such as irrigating golf courses, lawns, and crops, or for industrial purposes, if proper measures are taken to ensure its quality.

Moringa oleifera: a systematic review of its botany, traditional uses, phytochemistry, pharmacology and toxicity

OBJECTIVES

Moringa oleifera (M. oleifera) Lam (Moringaceae) is a perennial plant broadly used in South Asia and Africa as a traditional folk medicine to treat many ailments such as paralysis, helminthiasis, sores and skin infections. The review provides a critical and comprehensive evaluation of the botany, traditional uses, phytochemistry, pharmacology, toxicity, agricultural economy and dietary benefit of M. oleifera and its future perspectives.

KEY FINDINGS

In this review, the entire plant of M. oleifera, containing diverse phytochemicals, is summarized. The 163 chemical components, included flavonoids, carbamates, glucosinolates, phenols, and so on with various bioactivities, such as anti-tumour, antioxidant, anti-inflammatory, and so on. Additionally, M. oleifera is toxic at certain doses; and overuse can cause genotoxicity.

SUMMARY

Although M. oleifera has been widely used in traditional medicine, the pharmacological studies that have been conducted so far are not sufficient for its use in the setting of evidence-based medicine. Little relevant data from clinical trials of M. oleifera have been reported. The majority of studies of its constituents, such as carbamates and glucosinolates, have been conducted only in vitro. Owing to a lack of available data, the pharmacology, toxicity, agricultural economy and dietary benefit of its constituents and extracts require further evaluation.

Effects of Moringa oleifera leaf extracts and its bioactive compound gallic acid on reducing toxicities of heavy metals and metalloid in Saccharomyces cerevisiae

Moringa oleifera leaf extract is rich in antioxidants and has high potential for use to alleviate metal toxicity. Previously, we have reported the roles of aqueous M. oleifera leaf extract in mitigating intracellular cadmium (Cd) accumulation and Cd-induced oxidative stress. In this study, we investigated the protective role of aqueous and/or ethanolic M. oleifera leaf extracts (AMOLE and/or EMOLE) against other metal(loid)s in the eukaryotic model Saccharomyces cerevisiae. Our results show that only the AMOLE remarkably promoted the growth of yeast cells grown in the presence of arsenite (As(III)), Cd, nickel (Ni), and lead (Pb). Although the AMOLE contained lower amount of total phenolic and flavonoid contents and displayed lower DPPH scavenging capacity than the EMOLE, both AMOLE and EMOLE had the same capacity for reducing intracellular ROS levels in yeast cells exposed to As(III), Cd, Ni, and Pb. Moreover, the AMOLE was more effective than the EMOLE in inhibiting intracellular accumulation of these toxic metal(loid)s. In addition, we found that gallic acid, one of important phenolic constituents present in both extracts, could protect yeast cells against As(III) toxicity, likely through its role in decreasing As(III) accumulation and As(III)-induced ROS production. Furthermore, the hydroxyl and carboxyl groups of gallic acid appear to play a critical role in chelating As(III). The present study suggests the promising applications of the AMOLE (and also gallic acid) as protective agents against hazardous metal(loid)s.

A review of properties, nutritional and pharmaceutical applications of Moringa oleifera: integrative approach on conventional and traditional Asian medicine

Moringa oleifera L. from the Moringaceae family is a perennial tree widely cultivated in many tropic regions and easily grown even in adverse conditions. M. oleifera is also known as the miracle tree, which for centuries has been indicated for traditional medicine. With no reports of side effects, in doses achievable by ingestion, different parts of M. oleifera is used to treat several conditions, such as malnutrition, diabetes, blindness, anemia, hypertension, stress, depression, skin, arthritis, joints and kidney stones disorders. This plant also showed capacity of helping in maintenance of the cardiovascular system health, blood-glucose levels and providing anti-oxidant, anti-inflammatory and anti-cancer activity as well as the regulation of urinary tract and lactation in nursing women. The seed and leaves powder has water purification properties through flocculation. It also supplements the food in the human diet and in the fortification of livestock feed, especially in developing countries. So, M. oleifera properties have also been applied to cosmetic and byproducts industries due to the high nutritive and protective properties of its seed oil. According to the holistic or traditional medicine, M. oleifera has very relevant therapeutic properties and applications depending on the constitution, somatic and psychological needs of patients. It is usually referred as a natural product that can treat different physical and psychological health aspects, offering an energetic action and structural rebuilder of the body and promoting emotions of highly positive attitudes towards life. The high and specific immunological potential of M. oleifera leads us to suggest an in-depth study to assess the hypothesis of conferring a supportive effect against Covid-19 disease.

Biological, nutritional, and therapeutic significance of Moringa oleifera Lam

The genus Moringa Adans. comprises 13 species, of which Moringa oleifera Lam. native to India and cultivated across the world owing to its drought and frost resistance habit is widely used in traditional phytomedicine and as rich source of essential nutrients. Wide spectrum of phytochemical ingredients among leaf, flower, fruit, seed, seed oil, bark, and root depend on cultivar, season, and locality. The scientific studies provide insights on the use of M. oleifera with different aqueous, hydroalcoholic, alcoholic, and other organic solvent preparations of different parts for therapeutic activities, that is, antibiocidal, antitumor, antioxidant, anti-inflammatory, cardio-protective, hepato-protective, neuro-protective, tissue-protective, and other biological activities with a high degree of safety. A wide variety of alkaloid and sterol, polyphenols and phenolic acids, fatty acids, flavanoids and flavanol glycosides, glucosinolate and isothiocyanate, terpene, anthocyanins etc. are believed to be responsible for the pragmatic effects. Seeds are used with a view of low-cost biosorbent and coagulant agent for the removal of metals and microbial contamination from waste water. Thus, the present review explores the use of M. oleifera across disciplines for its prominent bioactive ingredients, nutraceutical, therapeutic uses and deals with agricultural, veterinarian, biosorbent, coagulation, biodiesel, and other industrial properties of this "Miracle Tree."

Moringa oleifera (drumstick tree) seed coagulant protein (MoCP) binds cadmium - preparation and characterization of nanoparticles

Moringa oleifera is grown globally. It is a multipurpose tree and the seeds are rich in phytochemicals with antimicrobial activities. The crude powder of seeds clarify the turbid and metal contaminated water. M. oleifera (drumstick tree) seed coagulant protein (MoCP) was isolated to homogeneity from the crude extracts by carboxymethyl cellulose chromatography (CMC) and gel filtration. The molecular weight of the protein on gel filtration was 13 kDa and in SDS-PAGE it migrated as a single band under reducing conditions with molecular mass of 6.5 kDa (dimeric). Immobilized MoCP selectively binds cadmium from aqueous solutions (pH 2.0-7.0) with maximum binding at pH 6.0 in 180 min when tested at 10-600 minutes. It also bound the metal in the concentration range of 30-70mgL-1. The adsorption kinetics was better described by pseudo second order and the data better explained by freundlich isotherm model than Langmuir isotherm model as in Freundlich model the correlation coefficient (R2) is high and the calculated qmax is very close to the experimental qmax rather than Langmuir isotherm model. Furthermore, the nanoparticles of MoCP were prepared and characterized using transmission electron microscopy (TEM). The authenticity of the isolated protein and the nanopraticles prepared was confirmed by specific reactivity with the MoCP antibody raised earlier in our laboratory.

Field Application of the Micro Biological Survey Method for the Assessment of the Microbiological Safety of Different Water Sources in Horn of Africa and the Evaluation of the Effectiveness of Moringa Oleifera in Drinking Water Purification

Water monitoring requires expensive instrumentations and skilled technicians. In developing Countries as Africa, the severe economic restrictions and lack of technology make water safety monitoring approaches applied in developed Countries, still not sustainable. The need to develop new methods that are suitable, affordable, and sustainable in the African context is urgent. The simple, economic and rapid Micro Biological Survey (MBS) method does not require an equipped laboratory nor special instruments and skilled technicians, but it can be very useful for routine water analysis. The aim of this work was the application of the MBS method to evaluate the microbiological safety of different water sources and the effectiveness of different drinking water treatments in the Horn of Africa. The obtained results have proved that this method could be very helpful to monitor water safety before and after various purification treatments, with the aim to control waterborne diseases especially in developing Countries, whose population is the most exposed to these diseases. In addition, it has been proved that Moringa oleifera water treatment is ineffective in decreasing bacterial load of Eritrea water samples.

Antidiabetic and Antioxidant Activities of Ethanolic Extract of Dried Flowers of Moringa oleifera in Streptozotocin-induced Diabetic Rats

This study was undertaken to determine the antidiabetic and antioxidant effects of oral administration of ethanolic extract of Moringa oleiferaflower on stretozotocin-induced diabetic rats at 100, 200, and 300 mg/kg b.w.

Thirty (30) male experimental albino rats were grouped randomly into six groups: groups A, B, and F are the control, diabetic control and reference drug groups, while C-E received 100, 200, and 300mg/kg b.w of the extract, respectively. Blood samples and organs were collected to assay for blood glucose level and antioxidant enzymes.

Levels of blood glucose, serum lipids and lipid peroxidation as well as aspartate aminotransferase (AST), alkaline phosphatase (ALP), and alanine aminotransferase (ALT) activities were significantly reduced (p<0.05) in STZ-induced diabetic rats orally administered ethanolic extract of M. oleifera flower. However, the body weight; catalase and superoxide dismutase activities were significantly increased (p < 0.05) when compared with the controls.

M. oleifera flower ethanolic extract administered orally therefore exhibited improved lipid metabolism, glucose-lowering potential and is hence beneficial in preventing diabetic complications as a result of lipid peroxidation and oxidative systems in streptozotocin-induced diabetic rats. It could thus be employed therapeutically in managing diabetes mellitus.

Application of mucilage from Dicerocaryum eriocarpum plant as biosorption medium in the removal of selected heavy metal ions

The ability of mucilage from Dicerocaryum eriocarpum (DE) plant to act as biosorption medium in the removal of metals ions from aqueous solution was investigated. Functional groups present in the mucilage were identified using Fourier transform infrared spectroscopy (FTIR). Mucilage was modified with sodium and potassium chlorides. This was aimed at assessing the biosorption efficiency of modified mucilage: potassium mucilage (PCE) and sodium mucilage (SCE) and comparing it with non-modified deionised water mucilage (DCE) in the uptake of metal ions. FTIR results showed that the functional groups providing the active sites in PCE and SCE and DCE include: carboxyl, hydroxyl and carbonyl groups. The chloride used in the modification of the mucilage did not introduce new functional groups but increased the intensity of the already existing functional groups in the mucilage. Results from biosorption experiment showed that DE mucilage displays good binding affinity with metals ions [Zn(II), Cd(II) Ni(II), Cr(III) and Fe(II)] in the aqueous solution. Increase in the aqueous solution pH, metal ions initial concentration and mucilage concentration increased the biosorption efficiency of DE mucilage. The maximum contact time varied with each species of metal ions. Optimum pH for [Zn(II), Cd(II) Ni(II) and Fe(II)] occurred at pH 4 and pH 6 for Cr(III). Kinetic models result fitted well to pseudo-second-order with a coefficient values of R(2) = 1 for Cd(II), Ni(II), Cr(III), Fe(II) and R(2) = 0.9974 for Zn(II). Biosorption isotherms conforms best with Freundlich model for all the metal ions with correlation factors of 0.9994, 0.9987, 0.9554, 0.9621 and 0.937 for Zn(II), Ni(II), Fe(II), Cr(III) and Cd(II), respectively. Biosorption capacity of DE mucilage was 0.010, 2.387, 4.902, 0688 and 0.125 for Zn(II), Cr(III), Fe(II), Cd(II) and Ni(II) respectively. The modified mucilage was found to be highly efficient in the removal of metal ions than the unmodified mucilage.

Evaluation of the antimicrobial activity of Moringa oleifera seed extract as a sustainable solution for potable water

We have provided a detailed antimicrobial study of the seed extract ofMoringa oleifera, a common medicinal plant.

Use ofMoringa oleifera(Moringa) Seed Pods andSclerocarya birrea(Morula) Nut Shells for Removal of Heavy Metals from Wastewater and Borehole Water

Use of nonedible seed pods ofMoringa oleifera(Moringa) tree and nutshells ofSclerocarya birrea(Morula) tree for removal of selected metal ions (lead, cadmium, copper, manganese, iron, zinc, and magnesium) from wastewater and borehole water samples was investigated. Removal parameters such as contact time, pH, temperature, particle size, sorbent dose, and initial metal concentration were optimized. Determination of residual metal ions after employing sorbent was done using flame atomic absorption spectroscopy (FAAS). Using 200 ng synthetic metal ion mixture in 50 mL of water sample, the optimized parameters for Moringa seed pods were 60 min contact time, 1.0 g of sorbent dose, pH 8, 100 μm sorbent particle size, and extraction temp 35°C. While using Morula nutshells, the optimized conditions were 120 min contact time, 2.0 g sorbent dose, pH 8, 100 μm sorbent particle size, and extraction temp of 35°C. The removal efficiency of acid treated sorbents was compared to that of untreated sorbents and it was found to be higher for acid treated sorbents. These nonedible plant parts for Morula and Moringa plants are proposed as a cheap, simple, and an effective alternative for purification of water contaminated with heavy metals.

Bioaccumulation characterization of zinc and cadmium by Streptomyces zinciresistens, a novel actinomycete

The bioaccumulation characteristics of Zn(2+) and Cd(2+) by a novel species, Streptomyces zinciresistens CCNWNQ0016(T), were investigated. S. zinciresistens accumulated Zn(2+) and Cd(2+) mainly on the cell wall followed by intracellular accumulation. The mycelium was deformed, aggregated and formed precipitate of zinc and cadmium on the cell surface. Electron dense granules were detected on the cell wall as well as within the cytoplasm. The amino, carboxyl, hydroxyl and carbonyl groups were responsible for the biosorption of Zn(2+) and Cd(2+). The Langmuir isotherm model fitted the experimental data of metals adsorption processes better than Freundlich isotherm model. Cu(2+) and Cr(3+) competed for adsorption sites on the cell surface with Zn(2+) and Cd(2+). 87.33% and 98.11% recovery of Zn(2+) and Cd(2+), respectively, could be obtained at pH≤2 from metal-loaded biomass of S. zinciresistens desorption.

A study of the removal of heavy metals from aqueous solutions by Moringa oleifera seeds and amine-based ligand 1,4-bis[N,N-bis(2-picoyl)amino]butane

Uptake for lead, copper, cadmium, nickel and manganese from aqueous solution using the Moringa oleifera seeds biomass (MOSB) and amine-based ligand (ABL) was investigated. Experiments on two synthetic multi-solute systems revealed that MOSB performed well in the biosorption and followed the decreasing orders Pb(II)>Cu(II)>Cd(II)>Ni(II)>Mn(II) and Zn(II)>Cu(II)>Ni(II). The general trend of the heavy metal ions uptake by the amine-based ligand followed decreased in the order Mn>Cd>Cu>Ni>Pb, which is the reverse trend for what was observed for MOSB. Comparing the single- and multi-metal solutions, there was no clear effect in the biosorption capacity of MOSB suggesting the presence of sufficient active binding sites for all metal ions studied. The MOSB performance is also not affected by pH in the range 3.5-8.

Anti-cyanobacterial activity of Moringa oleifera seeds

Filtrates from crushed Moringa oleifera seeds were tested for their effects on growth and Photosystem II efficiency of the common bloom-forming cyanobacterium Microcystis aeruginosa. M. aeruginosa populations exhibited good growth in controls and treatments with 4- and 8-mg crushed Moringa seeds per liter, having similar growth rates of 0.50 (+/-0.01) per day. In exposures of 20- to 160-mg crushed Moringa seeds L(-1), growth rates were negative and on average -0.23 (+/-0.05) .day(-1). Presumably, in the higher doses of 20- to 160-mg crushed seeds per liter, the cyanobacteria died, which was supported by a rapid drop in the Photosystem II efficiency (Phi(PSII)), while the Phi(PSII) was high and unaffected in 0, 4, and 8 mg L(-1). High-density populations of M. aeruginosa (chlorophyll-a concentrations of approximately 270 microg L(-1)) were reduced to very low levels within 2 weeks of exposure to >/=80-mg crushed seeds per liter. At the highest dosage of 160 mg L(-1), the Phi(PSII) dropped to zero rapidly and remained nil during the course of the experiment (14 days). Hence, under laboratory conditions, a complete wipeout of the bloom could be achieved. This is the first study that yielded evidence for cyanobactericidal activity of filtrate from crushed Moringa seeds, suggesting that Moringa seed extracts might have a potential as an effect-oriented measure lessening cyanobacterial nuisance.

Co-administration of monoisoamyl dimercaptosuccinic acid and Moringa oleifera seed powder protects arsenic-induced oxidative stress and metal distribution in mice

Arsenic contamination of groundwater in the West Bengal basin in India is unfolding as one of the worst natural geo-environmental disasters to date. Chelation therapy with chelating agents is considered to be the best known treatment against arsenic poisoning; however, they are compromised with certain serious drawbacks/side-effects. Efficacy of combined administration of Moringa oleifera (M. oleifera) (English: Drumstick tree) seed powder, a herbal extract, with a thiol chelator monoisoamyl DMSA (MiADMSA) post-arsenic exposure in mice was studied. Mice were exposed to 100 ppm arsenic in drinking water for 6 months, followed by 10-days treatment with M. oleifera seed powder (500 mg/kg, orally through gastric gavage, once daily), MiADMSA (50 mg/kg, intraperitoneally, once daily) either individually or in combination. Arsenic exposure caused significant decrease in blood glutathione, delta-aminolevulinic acid dehydratase (ALAD), accompanied by increased production of reactive oxygen species in blood and soft tissues. Significant inhibition of superoxide dismutase, catalase, and glutathione peroxidase activities in tissues (liver in particular) along with significant increase in thiobarbituric acid reactive substances and metallothionein levels in arsenic intoxicated mice was also noted. Combined administration of MiADMSA with M. oleifera proved better than all other treatments in the recovery of most of the above parameters accompanied by more pronounced depletion of arsenic. The results suggest that concomitant administration of M. oleifera during chelation treatment with MiADMSA might be a better treatment option than monotherapy with the thiol chelator in chronic arsenic toxicity.

Cadmium and zinc removal from aqueous solutions by Bacillus jeotgali: pH, salinity and temperature effects

Effects of pH, salinity and temperature on biosorption of Cd and Zn by bacteria Bacillus jeotgali strain U3 were evaluated in batch experiments. Traditional and Subsequent Addition Methods (SAM) were used to carry out the bioassays. Sorption of metals was higher when pH or temperature was increased, or when salinity was reduced. The Langmuir isotherm better fit the biosorption data for Cd, while the Freundlich model fitted better for Zn biosorption. A comparison with similar biosorbents suggested that Bacillus jeotgali strain U3 could be considered a good biosorbent for Cd and Zn recovery.

Influence of ultrasound on cadmium ion removal by sorption process

This study presents the removal of Cd(II) from aqueous solution by the sorption process in the presence (sono-sorption) and absence (conventional method) of ultrasound. Batch experiments were conducted to study the main parameters such as sorbate concentration, amount of sorbent, contact time, and ultrasound intensity. In addition, the sorbate/sorbent concentration ratios were studied in two different ways: (a) in a constant sorbate concentration and variable amount of sorbent, (b) in a constant amount of sorbent and variable sorbate concentration. The results indicated that under proper conditions, there was a possibility to remove cadmium ion very fast and efficiently from aqueous solution. In addition, the intensity of ultrasound and the sorbate/sorbent concentration ratio were two important factors for the removal of this pollutant and therefore, this study was focused mostly on these two variables.

Microbial and plant derived biomass for removal of heavy metals from wastewater

Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment. Conventional treatment technologies for removal of heavy metals from aqueous solution are not economical and generate huge quantity of toxic chemical sludge. Biosorption of heavy metals by metabolically inactive non-living biomass of microbial or plant origin is an innovative and alternative technology for removal of these pollutants from aqueous solution. Due to unique chemical composition biomass sequesters metal ions by forming metal complexes from solution and obviates the necessity to maintain special growth-supporting conditions. Biomass of Aspergillus niger, Penicillium chrysogenum, Rhizopus nigricans, Ascophyllum nodosum, Sargassum natans, Chlorella fusca, Oscillatoria anguistissima, Bacillus firmus and Streptomyces sp. have highest metal adsorption capacities ranging from 5 to 641 mg g(-1) mainly for Pb, Zn, Cd, Cr, Cu and Ni. Biomass generated as a by-product of fermentative processes offers great potential for adopting an economical metal-recovery system. The purpose of this paper is to review the available information on various attributes of utilization of microbial and plant derived biomass and explores the possibility of exploiting them for heavy metal remediation.

Innovative physico-chemical treatment of wastewater incorporating Moringa oleifera seed coagulant

Moringa oleifera is a pan tropical, multipurpose tree whose seeds contain a high quality edible oil (up to 40% by weight) and water soluble proteins that act as effective coagulants for water and wastewater treatment. The use of this natural coagulant material has not yet realised its potential. A water extract of M. oleifera seed was applied to a wastewater treatment sequence comprising coagulation-flocculation-sedimentation-sand filtration. The study was laboratory based using an actual wastewater. Overall COD removals of 50% were achieved at both 50 and 100mg/l M. oleifera doses. When 50 and 100mg/l seed doses were applied in combination with 10mg/l of alum, COD removal increased to 58 and 64%, respectively. The majority of COD removal occurred during the filtration process. In the tests incorporating alum, sludge generation and filter head loss increased by factors of 3 and 2, respectively. These encouraging treatment results indicate that this may be the first treatment application that can move to large scale adoption. The simple water extract may be obtained at minimal cost from the presscake residue remaining after oil extraction from the seed. The regulatory compliance issues of adopting 'new materials' for wastewater treatment are significantly less stringent than those applying to the production of potable water.

Ternary biosorption studies of Cd(II), Cr(III) and Ni(II) on shelled Moringa oleifera seeds

Competitive biosorption of Cd(II), Cr(III) and Ni(II) on unmodified shelled Moringa oleifera seeds (SMOS) present in ternary mixture were compared with the single metal solution. The extent of adsorption capacity of the ternary metal ions tested on unmodified SMOS was low (10-20%) as compared to single metal ions. SMOS removed the target metal ions in the selectivity order of Cd(II) > Cr(III) > Ni(II). Sorption equilibria, calculated from adsorption data, explained favorable performance of biosorption system. Regeneration of exhausted biomass was also attempted for several cycles with a view to restore the sorbent to its original state.

Moringa oleifera: a food plant with multiple medicinal uses

Moringa oleifera Lam (Moringaceae) is a highly valued plant, distributed in many countries of the tropics and subtropics. It has an impressive range of medicinal uses with high nutritional value. Different parts of this plant contain a profile of important minerals, and are a good source of protein, vitamins, beta-carotene, amino acids and various phenolics. The Moringa plant provides a rich and rare combination of zeatin, quercetin, beta-sitosterol, caffeoylquinic acid and kaempferol. In addition to its compelling water purifying powers and high nutritional value, M. oleifera is very important for its medicinal value. Various parts of this plant such as the leaves, roots, seed, bark, fruit, flowers and immature pods act as cardiac and circulatory stimulants, possess antitumor, antipyretic, antiepileptic, antiinflammatory, antiulcer, antispasmodic, diuretic, antihypertensive, cholesterol lowering, antioxidant, antidiabetic, hepatoprotective, antibacterial and antifungal activities, and are being employed for the treatment of different ailments in the indigenous system of medicine, particularly in South Asia. This review focuses on the detailed phytochemical composition, medicinal uses, along with pharmacological properties of different parts of this multipurpose tree.