Advances in Materials Science and Engineering

Review Article

Advances in Application of Natural Clay and Its Composites in Removal of Biological, Organic, and Inorganic Contaminants from Drinking Water

Table 1

Summary of the advances in application of natural clay and its composites in removing different contaminants from drinking water and its sources.


S. No.	Contaminants in drinking water sources	Type of clay and modification	Reference number	Efficiency	Effecting variable	Value of the effecting variable	Specific comments

I	Metals

	Cadmium	Kaolinite and montmorillonite and their modified forms bentonite	[26, 27]				Montmorillonite and its modified forms had higher metal adsorbing capacity
	Chromium		[29]
	Cobalt		[29, 30]
	Copper		[27, 29, 31, 32]
	Iron		[33]
	Lead		[34, 35]
	Manganese		[29]
	Nickel		[29, 32, 36]
	Zinc		[31, 37]
	Nickel Copper Cadmium Zinc	Bentonite clay iron oxide composite	[38]
	Lead and Cadmium	Beidellite	[39]	83.3–86.9 mg g⁻¹ 42–45.6 mg g⁻¹
	Tungsten	Montmorillonite coated with chitosan	[40]	23.9 mg g⁻¹	pH	4	Efficiency decreases with increase in PH
	Uranium	Thermally activated bentonite (TAB)	[41]	196 mLg⁻¹	Temperature pH	440°C 9	Efficiency increases with increase in temp and pH
	Lead and Zinc	Bentonite	[42]		Adsorbent dose	5 gL⁻¹ 20 gL⁻¹	Efficiency increases with increase in adsorbent dose.
	Hexavalent chromium	Montmorillonite supported magnetic nanoparticle	[43]	15.3 mg g⁻¹	pH
	Cobalt	Kaolinite and montmorillonite	[45]
	Copper Nickel Cobalt Manganese	Kaolinite and montmorillonite	[29]	11.0 mg g⁻¹
	Chromium	Chitosan-montmorillonite-Na (organo-nanoclay composite)	[16]		pH	3
	Arsenic	Calcined kaolin and bentonite pretreated with Fe²⁺, Fe³⁺, Al³⁺ and Mn²⁺	[46]	92–99% 50%	Type of metal pretreatment	Fe²⁺ and Mn²⁺ Fe³⁺ and Al³⁺
	Arsenic	Montmorillonite, kaolinite and Illite	[47]	90%	Concentration of sodium chloride
	Cadmium Chromium, Copper Mercury Lead Zinc	Mixed clay (illite, kaolinite, mixed layer minerals and nonclay mineral carbonate fluoroapatite	[48]	85% 90% 50% 60% 100% 92%	pH	6 and 9 5 <6.8 pH independent <7.67 <7
	Selenium	Chitosan montmorillonite	[52]	18.4 mg g⁻¹
	Arsenate and Arsenite	Ti-pillared montmorillonite	[53]	Greater than 60%	Temperature pH	25°C–45°C 5 for As(III) and 3 for AS(V)	Arsenite and arsenate removal decreased with increase in temperature but opposite trend was seen in the temperature range of 45°C–65°C in case of arsenate.
	Lead	Sodium montmorillonite clay-carboxy methyl cellulose composite	[54]
	Copper	Bentonite polyacrylamide composite	[55]	97%	pH	7	Increasing temperature and decrease in ionic strength favors copper adsorption.
	Lead Nickel Cadmium Copper	Bentonite-methylene bis-acrylamide	[56]	1666.67 mg g⁻¹ 270.27 mg g⁻¹ 416.67 mg g⁻¹ 222.2 mg g⁻¹

II	Inorganic contaminants

	Fluoride	Magnesium incorporated bentonite magnesium-bentonite manganese-bentonite	[57] [58]	95.45% No significant removal	Desorption	97%	Decreases the capacity of the desorbed MB from 95% to 75%.
		Lanthanum-bentonite		68%	pH	5	Fluoride removal decreases at alkaline pH
		Zirconium loaded bentonite	[59]	—	pH	Less than 6	Best removal is found below pH 6.
	Nitrates	Calcium montmorillonite activated by hydrochloric acid	[60]	22.28%	Stirring time	68 hours	13.74% removal was increased to 22.28% when stirring time increased from 0.5 hours to 68 hours

III	Organic contaminants

	Dichloroacetic acid	Bentonite-based Absorptive ozonation followed by catalytic oxidation by Fe³⁺	[61]	92%	Addition of Fe³⁺	5 mg L⁻¹	Increase of concentration of Fe³⁺ from 0.5 mg L⁻¹ to 5 mg L⁻¹ increased the removal efficiency from 68% to 92%
	Carbon tetrachloride	Quaternary ammonium salt-modified bentonite	[62]	70%
	Emerging contaminants: naproxen, salicylic acid, clofibric acid and carbamazepine	Inorganic-organic-intercalated (IO) bentonites	[63]	2.69 μmolg⁻¹ 5.55 μmolg⁻¹	Addition of different transition metal	varies	Ni < Cu < Co carbamazepine < clofibric acid < naproxen < salicylic acid
	Phenol	Bentonite modified with cationic surfactant, acetyl trimethyl ammonium bromide (CTAB)	[64]	333 mg g⁻¹	pH	9
	Humid acid and O-dichlorobenzene	Combined ozonation and bentonite coagulation	[65]	95% of HA and 74% of DCB	Iron	1–5 mg L⁻¹	increase of iron from 0–10 mg L⁻¹ in the system improved the adsorption efficiency for both HA and DCB
	Algae removal	Montmorillonite KSF	[66]	100%	Dose of clay	200 mg/L
	Blue green algae (Cyanobacterial microcystis aeruginosa)	Montmorillonite-Cu²⁺/Fe³⁺ oxides magnetic material	[67]	92%	Ratio of Clay: Cu²⁺/Fe³⁺	2 : 1	With increase in the ration from 1 : 1 to 2 : 1 removal efficiency increased from 48% to 92%
	Atrazine	4-vinylpyridine-co-styrene- montmorillonite	[68]	90–99%
	Atrazine, sulfentrazone, imazaquin and alachlor	Vesicle-clay complex (Di dodecyldimethylammonium bromide-montmorillonite)	[69]	60% atrazine and 90–100% for others	Presence of all the contaminants together		Presence of all the contaminants together had a synergistic effect in their removal
	Naphthalene and phenolic derivative	Crystal violet tetraphenyl phosphonium-montmorillonite	[70]	~99%	Organo clay dose	1.67 gL⁻¹
	Salicylic acid	Bentonite and kaolin	[71]	—	—	—	—
	Phenol nitro benzene	Cetyltrimethyl ammonium bromide	[72]	150 mg g⁻¹ 69 mg g⁻¹
	Carbamazepine	Modified smectite clays	[73]

IV	Pathogen

	Microcystin-LR	Natural clay minerals consisting of kaolin and montmorillonite	[74]	81%