<PAGE>   1

                                                        EXHIBIT 10.10.AA; PAGE 1

                                                  23456 South Pointe Drive
                                                  Laguna Hills, California 92653
                                                  949-770-9347  Fax 949-770-9209
ELECTROPURE, INC.
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                               WARRANT NO. A-3128

                             DATED JANUARY 11, 2001

                   Void after 5:00 P.M. Los Angeles City Time,
                               on January 11, 2006
               Warrant to Purchase 250,000 Shares of Common Stock


THIS WARRANT, AND THE COMMON STOCK ISSUABLE UPON ITS EXERCISE, HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933 AND MAY NOT BE SOLD, PLEDGED,
HYPOTHECATED, OR OTHERWISE TRANSFERRED, DISPOSED OF OR OFFERED FOR SALE, IN
WHOLE OR IN PART,, IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER
THAT ACT COVERING THIS WARRANT AND/OR THE COMMON STOCK ISSUABLE UPON ITS
EXERCISE, OR AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO ELECTROPURE, INC.
THAT AN EXEMPTION FROM REGISTRATION IS AVAILABLE.

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                        WARRANT TO PURCHASE COMMON STOCK

                                       OF

                                ELECTROPURE, INC.

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This is to certify that, for value received, ANTHONY M. FRANK, or assigns,
("Holder"), is entitled to purchase, subject to the provisions of this Warrant,
from ELECTROPURE, INC., a California corporation ("Company"), Two Hundred Fifty
Thousand (250,000 ) fully paid, validly issued and nonassessable shares of
Common Stock, $0.01 par value, of the Company ("Common Stock") at any time or
from time to time during the period from the date hereof until 5:00 P.M. Los
Angeles City Time on January 11, 2006 (the "Exercise Period") at an initial
exercise price equal to $0.47 per share. The number of shares of Common Stock to
be received upon the exercise of this Warrant and the price to be paid for each
share of Common Stock may be adjusted from time to time as hereinafter set
forth. The shares of Common Stock deliverable upon such exercise, and as
adjusted from time to time are hereinafter sometimes referred to as "Warrant
Shares" and the exercise price of a share of Common Stock in effect at any time
and as adjusted from time to time is hereinafter sometimes referred to as the
"Exercise Price."

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                                                        EXHIBIT 10.10.AA; PAGE 2

A. EXERCISE OF WARRANT. During and subject to the Exercise Period, this Warrant
may be exercised in whole or in part at any time and the Holder shall have the
right to exercise this Warrant into the kind and amount of shares of stock and
other securities and property (including cash) receivable by a holder of the
number of shares of Common Stock into which this Warrant might have been
exercisable immediately prior thereto. This Warrant may be exercised by
presentation and surrender hereof to the Company at its principal office, or at
the office of its stock transfer agent, if any, with the Purchase Form annexed
hereto duly executed and accompanied by payment of the Exercise Price for the
number of Warrant Shares specified in such form. As soon as practicable after
each such exercise of the Warrants, but not later than fourteen (14) days from
the date of such exercise, the Company shall issue and deliver to the Holder a
certificate or certificates for the Warrant Shares issuable upon such exercise,
registered in the name of the Holder or its designee. If this Warrant should be
exercised in part only, the Company shall, upon surrender of this Warrant for
cancellation, execute and deliver a new Warrant evidencing the rights of the
Holder thereof to purchase the balance of the Warrant Shares purchasable
thereunder. Upon receipt by the Company of this Warrant at its office, or by the
stock transfer agent of the Company at its office, in proper form for exercise,
the Holder shall be deemed to be the holder of record of the shares of Common
Stock issuable upon such exercise, notwithstanding that the stock transfer books
of the Company shall then be closed or that certificates representing such
shares of Common Stock shall not then be physically delivered to the Holder.

B. RESERVATION OF SHARES. The Company shall at all times reserve for issuance
and/or delivery upon exercise of this Warrant such number of shares of its
Common Stock as shall be required for issuance and delivery upon exercise of the
Warrants.

C. FRACTIONAL SHARES. No fractional shares or script representing fractional
shares shall be issued upon the exercise of this Warrant. With respect to any
fraction of a share called for upon any exercise hereof, the Company shall pay
to the Holder an amount in cash equal to such fraction multiplied by the current
market value of a share, determined as follows:

        (1) If the Common Stock is listed on a National Securities Exchange or
admitted to unlisted trading privileges on such exchange or listed for trading
on the NASDAQ system, the current market value shall be the last reported sale
price of the Common Stock on such exchange or system on the last business day
prior to the date of exercise of this Warrant or if no such sale is made on such
day, the average closing bid and asked prices for such day on such exchange or
system; or

        (2) If the Common Stock is not so listed or admitted to unlisted trading
privileges, the current market value shall be the mean of the last reported bid
and asked prices reported by the National Quotation Bureau, Inc. on the last
business day prior to the date of the exercise of this Warrant; or

        (3) If the Common Stock is not so listed or admitted to unlisted trading
privileges and bid and asked prices are not so reported, the current market
value shall be an amount, not less than book value thereof as at the end of the
most recent fiscal year of the Company ending prior to the date of the exercise
of the Warrant, determined in such reasonable manner as may be prescribed by the
Board of Directors of the Company or, if higher, $0.01 per share.


<PAGE>   3

                                                        EXHIBIT 10.10.AA; PAGE 3

D. EXCHANGE, TRANSFER, ASSIGNMENT OR LOSS OF WARRANT. This Warrant is
exchangeable, without expense, at the option of the Holder, upon presentation
and surrender hereof to the Company or at the office of its stock transfer
agent, if any, for other warrants of different denominations entitling the
holder thereof to purchase in the aggregate the same number of shares of Common
Stock purchasable hereunder. Upon surrender of this Warrant to the Company at
its principal office or at the office of its stock transfer agent, if any, with
the Assignment Form annexed hereto duly executed and funds sufficient to pay any
transfer tax, the Company shall, without charge, execute and deliver a new
Warrant I the name of the assignee named in such instrument of assignment and
this Warrant shall promptly be canceled. This Warrant may be divided or combined
with other warrants which carry the same rights upon presentation hereof at the
principal office of the Company or at the office of its stock transfer agent, if
any, together with a written notice specifying the names and denominations in
which new Warrants are to be issued and signed by the Holder hereof. The term
"Warrant" as used herein includes any Warrants into which this Warrant may be
divided or exchanged. Upon receipt of the Company of evidence satisfactory to it
of the loss, theft, destruction or mutilation of this Warrant, and (in the case
of loss, theft or destruction) of reasonably satisfactory indemnification, and
upon surrender and cancellation of this Warrant, if mutilated, the Company will
execute and deliver a new Warrant of like tenor and date. Any such new Warrant
executed and delivered shall constitute an additional contractual obligation on
the part of the Company, whether or not this Warrant so lost, stolen, destroyed,
or mutilated shall be at any time enforceable by anyone.

E. RIGHTS OF THE HOLDER. The Holder shall not, by virtue hereof, be entitled to
any rights of a shareholder in the Company, either at low or equity, and the
rights of the Holder are limited to those expressed in the Warrant and are not
enforceable against the Company except to the extent set forth herein.

F. ANTI-DILUTION PROVISIONS. The Exercise Price in effect at any time and the
number and kind of securities purchasable upon the exercise of the Warrants
shall be subject to adjustment from time to time upon the happening of certain
events as follows:

        (1) In case the Company shall (i) declare a dividend or make a
contribution on its outstanding shares of Common Stock in shares of Common
Stock, (ii) subdivide or reclassify its outstanding shares of Common Stock into
a greater number of shares, or (iii) combine or reclassify its outstanding
shares of Common Stock into a smaller number of shares, the Exercise Price in
effect at the time of the record date for such dividend or distribution or of
the effective date of such subdivisions, combination or reclassification shall
be adjusted so that it shall equal the price determined by multiplying the
Exercise Price by a fraction, the denominator of which shall be the number of
shares of Common Stock outstanding after giving effect to such action, and the
numerator of which shall be the number of shares of Common Stock outstanding
immediately prior to such action. Such adjustment shall be made successively
whenever any event listed above shall occur.

        (2) Whenever the Exercise Price payable upon exercise of each Warrant is
adjusted pursuant to Subsection (1) above, the number of shares purchasable upon
exercise of this Warrant shall simultaneously be adjusted by multiplying the
number of shares initially issuable upon exercise of this Warrant by the
Exercise Price in effect on the date hereof and dividing the product so obtained
by the Exercise Price, as adjusted.



<PAGE>   4

                                                        EXHIBIT 10.10.AA; PAGE 4

        (3) Whenever the Exercise Price is adjusted, as herein provided, the
Company shall promptly cause a notice setting forth the adjusted Exercise Price
and adjusted number of shares issuable upon exercise of each Warrant to be
mailed to the Holders, at their last addresses appearing in the Warrant
Register, and shall cause a certified copy thereof to be mailed to its transfer
agent, if any. The Company may retain a firm of independent certificate public
accountants selected by the Board of Directors (who may be the regular
accountants employed by the Company) to make any computation required by this
Section F and a certificate signed by such firms shall be conclusive evidence of
the correctness of such adjustment.

        (4) In the event that at any time, as a result of an adjustment made
pursuant to Subsection (1) above, the Holder of this Warrant thereafter shall
become entitled to receive any shares of the Company, other than Common Stock,
thereafter the number of such other shares so receivable upon exercise of this
Warrant shall be subject to adjustment from time to time in a manner and on
terms as nearly equivalent as practicable to the provisions with respect to the
Common Stock contained in Subsection (1) above.

        (5) Irrespective of any adjustments in the Exercise Price or the number
or kind of shares purchasable upon exercise of this Warrant, Warrants
theretofore or thereafter issued may continue to express the same price and
number and kind of shares as are stated in the similar Warrants initially
issuable pursuant to this Agreement.

G. OFFICER'S CERTIFICATE. Whenever the Exercise Price shall be adjusted as
required by the provisions of the foregoing Section, the Company shall forthwith
file in the custody of its Secretary or an Assistant Secretary at its principal
office and with its stock transfer agent, if any, an officer's certificate
showing the adjusted Exercise Price determined as herein provided, setting forth
in reasonable detail the facts requiring such adjustment, including a statement
of the number of additional shares of Common Stock, if any, and such other facts
as shall be necessary to show the reason for and the manner of computing such
adjustment. Each such officer's certificate shall be made available at all
reasonable times for inspection by the holder or any holder of a Warrant
executed and delivered pursuant to Section A and the Company shall, forthwith
after each such adjustment, mail a copy by certified mail of such certificate to
the Holder or any such holder.

H. NOTICES TO WARRANT HOLDERS. So long as this Warrant shall be outstanding, (i)
if the Company shall pay any dividend or make any distribution upon the Common
Stock or (ii) if the Company shall offer to the holders of Common Stock for
subscription or purchase by them any share of any class or any other rights or
(iii) if the capital reorganization of the Company, reclassification of the
capital stock of the Company, consolidation or merger of the Company with or
into another corporation, sale, lease or transfer of all or substantially all of
the property and assets of the Company to another corporation, or voluntary or
involuntary dissolution, liquidation or winding up of the Company shall be
effected, then in any such case, the Company shall cause to be mailed by
certified mail to the Holder, at least fifteen days prior to the date specified
in (x) or (y) below, as the case may be, a notice containing a brief description
of the proposed action and stating the date on which (x) a record is to be taken
for the purpose of such dividend, distribution or rights, or (y) such
reclassification, reorganization, consolidation, merger, conveyance, lease,
dissolution, liquidation or winding up is to take place and the date, if any is
to be fixed, as of which the holders of Common Stock or other securities shall
receive cash or other property deliverable upon such reclassification,
reorganization, consolidation, merger, conveyance, dissolution, liquidation or
winding up.


<PAGE>   5

                                                        EXHIBIT 10.10.AA; PAGE 5


I. RECLASSIFICATION, REORGANIZATION OR MERGER. In case of any reclassification,
capital reorganization or other change of outstanding shares of Common Stock of
the Company, or in case of any consolidation or merger of the Company with or
into another corporation (other than a merger with a subsidiary in which merger
the Company is the continuing corporation and which does not result in any
reclassification, capital reorganization or other change of outstanding shares
of Common Stock of the class issuable upon exercise of this Warrant) or in case
of any sale, lease or conveyance to another corporation of the property of the
Company as an entirety, the Company shall, as a condition precedent to such
transaction, cause effective provisions to be made so that the Holder shall have
the right thereafter by exercising this Warrant at any time prior to the
expiration of the Warrant, to purchase the kind and amount of shares of stock
and other securities and property receivable upon such reclassification, capital
reorganization and other change, consolidation, merger, sale or conveyance by a
holder of the number of shares of Common Stock which might have been purchased
upon exercise of this Warrant immediately prior to such reclassification,
change, consolidation, merger, sale or conveyance. Any such provision shall
include provision for adjustments which shall be as nearly equivalent as may be
practicable to the adjustments provided for in this Warrant. The foregoing
provisions of this Section J shall similarly apply to successive
reclassifications, capital reorganizations and changes of shares of Common Stock
and to successive consolidations, mergers, sales or conveyances. In the event
that in connection with any such capital reorganization or reclassification,
consolidation, merger, sale or conveyance, additional shares of Common Stock
shall be issued in exchange, conversion, substitution or payment, in whole or in
part, for a security of the Company other than Common Stock, any such issue
shall be treated as an issue of Common Stock covered by the provisions of
Subsection (1) of Section F hereof.

        IN WITNESS THEREOF, the Company has caused this Warrant to be signed and
attested by the Undersigned, being duly authorized, as of the date set forth on
the first part hereof.

                                               ELECTROPURE, INC.

                                               By: /s/ CATHERINE PATTERSON
                                                   -----------------------------
                                                       CATHERINE PATTERSON
                                                       CORPORATE SECRETARY

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                                                        EXHIBIT 10.10.AA; PAGE 6

                                                 23456 South Pointe Drive
                                                 Laguna Hills, California 92653
                                                 949-770-9347   Fax 949-770-9209


ELECTROPURE, INC.
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                                  PURCHASE FORM

                               WARRANT NO. A-3128

                             DATED JANUARY 11, 2001





Dated:____________________, _____


The undersigned hereby irrevocably elects to exercise the within Warrant to the
extent of purchasing _________________ shares of Common Stock and hereby makes
payment of $____________________ in payment of the actual exercise price
thereof.

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                     INSTRUCTIONS FOR REGISTRATION OF STOCK

Name ___________________________________________________________________________
                  (Please typewrite or print in block letters)


Address ________________________________________________________________________



                                                  ------------------------------
                                                  Signature of Warrant Holder


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                                                        EXHIBIT 10.10.AA; PAGE 7


                                                  23456 South Pointe Drive
                                                  Laguna Hills, California 92653
                                                  949-770-9347  Fax 949-770-9209

ELECTROPURE, INC.
================================================================================


                                ASSIGNMENT FORM

                               WARRANT NO. A-3128

                             DATED JANUARY 11, 2001


FOR VALUE RECEIVED, the undersigned Warrant Holder hereby sells, assigns and
transfers unto:

         Name __________________________________________________________________
                      (Please typewrite or print in block letters)

         Address _______________________________________________________________


the right to purchase Common Stock represented by this Warrant to the extent of
____________ shares as to which such right is exercisable and does hereby
irrevocably constitute and appoint ________________________________ Attorney, to
transfer the same on the books of the Company with full power of substitution in
the premises.


Dated:_________________, _____


                                                 By: ___________________________
                                                     Signature of Warrant Holder